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Biomedical subjects

Subha V Raman

Publications and source records attributed to Subha V Raman.

At least 19 recordsLinked to original sources
PubMed2007

Aortic pathophysiology by cardiovascular magnetic resonance in patients with clinical suspicion of coronary artery disease.

PURPOSE: To correlate cardiovascular magnetic resonance (CMR)-based measurement of aortic pulse wave velocity (PWV) with serum markers for atherosclerosis and plaque burden in the thoracic aorta. METHOD: Individuals with risk factors for coronary atherosclerosis underwent CMR pulse wave velocity examination of the descending thoracic aorta and computed tomography for coronary calcium scoring. Inversion recovery images allowed quantification of aortic plaque. Serum lipids and c-reactive protein levels were measured. RESULTS: Mean PWV did not correlate with presence of aortic plaque (p = 0.55). Subgroup analysis showed no significant correlation with PWV and total plaque. PWV and pulse pressure correlated (PP) (R2 0.38, p = 0.0003), but PWV and other predictor variables did not. Total plaque area correlated with aortic diameter (p = 0.0066). CONCLUSIONS: In patients with suspected coronary artery disease, aortic pulse wave velocity reflects increased aortic stiffness demonstrated by elevated pulse pressure, but does not directly correlate with aortic plaque or serum markers for arterial disease.

Adult↗
PubMed2006

Unique application of multislice computed tomography in adults with congenital heart disease.

PURPOSE: Adults with congenital heart disease (CHD) form a growing population of patients requiring coronary artery assessment. In light of their increased incidence of coronary anomalies and need for reoperations, it is important to define their coronary anatomy. The purpose of this study was to define the spectrum of coronary artery anatomies and feasibility of coronary artery delineation in adults with CHD using 16- and 64-slice computed tomography angiography. MATERIALS AND METHODS: Coronary multislice computed tomography (MSCT) examinations performed in adults with CHD between 2004 and 2005 were reviewed with institutional review board approval. Informed consent was not required. In addition to image quality, the following coronary parameters were evaluated by analysis of axial, multiplanar reformatted, and volume-rendered images: (1) relationship to great arteries, (2) ostia number and location, (3) proximal course, (4) length of vessel seen, and (5) dominance. RESULTS: Eighty-five examinations in adults with CHD adults were identified. The relationship of the great vessels, number and location of the coronary ostia, and proximal course of the coronaries could be identified in all studies. Coronary anomalies were detected in 16 (19%) subjects. The entire coronary tree was visible in 77 (91%) of subjects. CONCLUSIONS: MSCT provides detailed, noninvasive assessment of complex coronary artery anatomy in adults with CHD. MSCT should be considered a useful modality in the assessment of these patients, as it does not require arterial access and provides detailed 3-dimensional anatomic information that has important implications for long-term management.

Adult↗
PubMed2006

Detection of coronary artery disease in orthotopic heart transplant recipients with 64-detector row computed tomography angiography.

Cardiac transplant recipients develop coronary artery disease in the form of cardiac allograft vasculopathy (CAV), and still undergo annual left heart catheterizations for detection at most centers. We prospectively enrolled 20 cardiac transplant recipients scheduled for annual left heart catheterization with X-ray coronary angiography (XRA) to also undergo electrocardiographically gated coronary computed tomography angiography (CTA), which was performed on a 64-detector computed tomography scanner. CTA detected more CAV vs XRA in 4 patients and less CAV in 0 patient, resulting in good overall agreement between the two modalities (kappa = 0.69). CTA may be superior to conventional catheter-based angiography to identify non-obstructive vessel wall disease that may go unrecognized with catheter-based angiography alone.

Adult↗
PubMed2006

Correlation of magnetic resonance imaging with histopathology in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C).

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is an asymptomatic cardiac disease characterized by fatty infiltration of the right ventricular myocardium and often results in sudden cardiac death. ARVD/C diagnosis includes the assessment of fatty infiltration, which can be achieved noninvasively with cardiovascular magnetic resonance (CMR). The standard CMR protocol places the signal-generating coil directly on the anterior chest wall and produces a nonspecific high intensity signal that obscures the high signal from fatty infiltration. The aim of this study was to determine whether increasing the coil-to-chest distance would improve identification of fatty infiltration. Thoraces from seven embalmed cadavers were imaged on a conventional 1.5 Tesla CMR scanner using the control protocol and an experimental protocol, with a 6 cm coil-to-chest distance. A representative axial MR image and corresponding gross section of the heart were analyzed in each case. Fatty infiltration was graded in a blinded fashion on the MR images with independent histopathologic assessment. In five of the seven cases, the experimental protocol provided a correlation between CMR and histopathology that was as good as or better than the control protocol. The experimental protocol was also better in preventing false positive diagnosis in cases of minimal infiltration. Thus, the experimental protocol showed a stronger correlation with histopathology than did the control protocol. Increasing the distance between the anterior surface coil and chest wall may improve classification of presence or absence of fatty infiltration in the right ventricular myocardium, potentially improving the noninvasive detection of ARVD/C with CMR.

Adipose Tissue↗
PubMed2006

An unusual cause of susceptibility artifact in magnetic resonance imaging.

Magnetic susceptibility artifact has been documented with various implants and devices, which require appropriate identification with screening of patients prior to subjecting them to magnetic resonance examination. We performed cardiovascular magnetic resonance (CMR) examination of the aorta in a 24-year-old woman in the setting of repaired aortic coarctation, and found magnetic susceptibility artifact arising from the stomach in the absence of known susceptibility artifact-producing material in this region. Further history revealed that she had ingested a prenatal vitamin prior to imaging, prompting experimental analyses that led us to conclude that iron-containing vitamins may be a source of magnetic susceptibility artifact.

Adult↗
PubMed2006

Multi-detector row cardiac computed tomography accurately quantifies right and left ventricular size and function compared with cardiac magnetic resonance.

BACKGROUND: Cardiac magnetic resonance (CMR) accurately quantifies right ventricular (RV) and left ventricular (LV) volumes and function. Limited availability of CMR and increasing use of MR-incompatible cardiovascular devices underscore the potential utility of cardiac computed tomography (CT) for ventricular quantification. This study quantified biventricular size and systolic function with multi-detector row CT compared with CMR imaging. METHODS: Twenty-six subjects prospectively underwent CT and CMR examinations on a 16-detector CT and 1.5 T MR scanner, respectively; claustrophobia in one and nongated CT imaging in another precluded complete imaging in 2 subjects. Contiguous multiphase short-axis images were generated from axial CT data, and steady-state free precession cine MR produced contiguous short-axis cines. Semiautomated software generated ventricular borders to calculate volume, mass, and ejection fraction (EF) from both sets of images. Blinded observers completed quantification and wall motion analyses of 23 CMR and CT data sets independently. RESULTS: All measures of LV size and function by cardiac CT correlated well with CMR over a wide range of LV function (LVEF 30%-72% by CMR), including end-diastolic volume (r = 0.97), end-systolic volume (r = 0.97), EF (r = 0.97), and mass (r = 0.95). Of 24 cases, 6 had inadequate contrast opacification of the RV precluding RV segmentation. In the remaining 18 CMR-CT data pairs, RVEF showed moderate agreement (r = 0.86), and RV volumes correlated well (r = 0.97 and 0.94 for RV end-diastolic volume and RV end-systolic volume, respectively). Ten percent of LV segments visualized by CT were inadequate for wall motion assessment due to motion artifact or inadequate contrast between myocardium and endocardium. For segments adequately visualized by both techniques, the mean kappa statistic was 0.88 (range 0.78-1.0), consistent with good agreement. CONCLUSION: Cardiac CT accurately quantifies LV size and function; RV quantification with cardiac CT requires optimized contrast opacification of the RV.

Aged↗
PubMed2006

Technical considerations for myocardial revascularization in congenital bilateral hypoplasia of the pericardium.

Congenital hypoplasia of the pericardium is a rare clinical condition that is typically encountered as an incidental finding during routine thoracic imaging or cardiothoracic surgery. Chest pain symptoms, when they occur, are often initially attributed to coronary ischemic syndromes, but herniation of cardiac structures through the pericardial defect, ischemia from torsion of great vessels, or compression of pulmonary parenchyma through defects between the aortic and pulmonary arteries can occur. Careful attention to cannulation techniques, conduit length, and the aberrant course of the phrenic nerves, typically through pericardial fibrous bands, is critical to the successful conduct of cardiac surgery.

Aged↗
PubMed2006

Myocardial ischemia and right ventricular dysfunction in adult patients with sickle cell disease.

BACKGROUND AND OBJECTIVES: Patients with sickle cell disease (SCD) have multi-organ manifestations of microvascular disease, though cardiac manifestations have been poorly characterized in vivo. This study sought to characterize myocardial characteristics in adult patients with SCD. DESIGN AND METHODS: Twenty-two consecutive outpatients and 11 age-matched controls underwent magnetic resonance imaging to assess myocardial perfusion reserve as well as left and right ventricular size and function and myocardial iron. Computed tomography of the coronary arteries was performed to assess epicardial coronary stenosis. RESULTS: Three of 22 outpatients with clinically stable SCD and no controls had abnormal myocardial perfusion reserve limited to the subendocardium, consistent with microvascular disease. Coronary arteries were free of disease as detectable by computed tomography angiography. Myocardial T2* was normal in all subjects (29 +/- 5 ms, median 29 ms), consistent with absence of cardiac iron deposition despite a high prevalence of hepatic iron overload (liver T2* 14 +/- 9 ms, median 12.0 ms). SCD patients had right ventricular enlargement and dysfunction (right ventricular ejection fraction 45 +/- 15 in SCD patients vs. 58 +/- 5% in controls, p=0.001) even in the absence of overt pulmonary hypertension. INTERPRETATION AND CONCLUSIONS: A subset of adult SCD patients may have myocardial ischemia in the absence of infarcted myocardium, myocardial iron overload, or coronary artery disease. Right ventricular dysfunction is present in stable SCD patients, despite normal resting pulmonary artery pressures. These findings could represent under-recognized mechanisms for chest pain and mortality in this population, and warrant further investigation in SCD crises.

Adult↗
PubMed2005

Usefulness of multidetector row computed tomography to quantify right ventricular size and function in adults with either tetralogy of Fallot or transposition of the great arteries.

An ever-increasing number of patients with congenital heart disease are reaching adulthood; follow-up often requires right ventricular (RV) quantification. Complex anatomy, acoustic window, and active implants such as pacemakers may limit modalities, such as echocardiography and cardiac magnetic resonance imaging (MRI), in this population. Recent advances in multidetector row cardiac computed tomography (MDCT) allow multiphase, multislice reconstructions in any plane but have not been applied to RV quantification. Fourteen patients with tetralogy of Fallot or transposition of the great arteries underwent cardiac MRI and MDCT examinations, with comparable quantification of RV volumes and ejection fractions and no systematic error by Bland-Altman analysis using MRI as the gold standard.

Adolescent↗
PubMed2005

Cardiovascular magnetic resonance in endocardial fibroelastosis.

Endomyocardial fibroelastosis is a rare disorder marked by characteristic morphological changes of the endocardium. We report a case of endomyocardial fibroelastosis diagnosed by late gadolinium-enhanced CMR and confirmed by endomyocardial biopsy. The patient improved following treatment with imatinib.

Adult↗
PubMed2005

Volumetric cine CMR to quantify atrial structure and function in patients with atrial dysrhythmias.

PURPOSE: To implement a cardiac magnetic resonance (CMR)-based protocol to define atrial structure and function in individuals with paroxysmal atrial fibrillation (PAF), heritable cardiac conduction and myocardial disease with atrial dysrhtyhmias (HCCMD), and healthy controls. METHODS: Fifteen controls, 20 PAF, and 12 HCCMD subjects underwent CMR examination including: multislice short-axis cine, multislice horizontal long-axis cine, and gadolinium-enhanced coronal plane magnetic resonance angiography (MRA) for pulmonary vein analysis. We also assessed for ventricular myopathy with delayed myocardial enhancement (DME) acquisitions. RESULTS: Right and left ventricular measurements did not differ among the three groups. Seven heritable atrial dysrhythmia subjects and no control or PAF subjects demonstrated midmyocardial fibrosis of the basal interventricular septum by DME. Left atrial (LA) volume at the onset of atrial systole and minimal LA volume were significantly higher in PAF subjects compared to controls (p < 0.05 for both), LA percent emptying was significantly lower in PAF subjects (p < 0.01), and RA percent emptying was significantly lower in PAF subjects compared to controls (p < 0.01), though these differences were not significant when controlling for heart rate, age and gender. There was no significant difference in right atrial (RA) volumes among study groups. Atrial volumes and function did not differ significantly between heritable atrial dysrhtyhmia subjects and controls. PAF subjects had greater frequency of a right middle pulmonary vein (RMPV) than controls (6/20 vs. 3/15) that did not reach statistical significance. CONCLUSIONS: CMR can quantify atrial structure and function in patients with PAF compared to controls. This protocol could not detect abnormalities in atrial function in early affected patients with heritable cardiomyopathy and atrial premature beats.

Adult↗
PubMed2005

A parent-driven, computer-based vaccine information system: addressing variability in information needs for the varicella vaccine.

OBJECTIVE: To determine the variability of parental interest in the depth of detail provided regarding vaccine information. PARTICIPANTS AND METHODS: We performed a cross-sectional, observational study in a primary care pediatric practice from September 1 to September 30, 1995. We provided each participant an opportunity to use a self-directed, computer-based information system using the varicella vaccine as a prototype. The system covered 7 topics regarding the vaccine and offered 5 stages of information, ranging from general, indisputable information at stage 1 to less common, potentially unresolved details at stage 5. Parents viewed stage 1 information for each topic. Parents would then choose to either view more stages or view the next topic. RESULTS: Of 130 parents visiting the pediatric practice, 112 (86%) agreed to participate. We found substantial variability in the amount of information sought. Some parents stopped with stage 1 information (15%-45%, depending on the topic), whereas others indicated they would seek more information beyond the fifth stage (2%-14%). Overall, parents reported high satisfaction with the system. CONCLUSION: Quantifiable variability exists in parents' requirements for vaccine information, and our information system addresses this issue.

Adult↗
PubMed2004

Usefulness of multislice computed tomography angiography to evaluate intravascular stents and transcatheter occlusion devices in patients with d-transposition of the great arteries after mustard repair.

Percutaneous interventions can treat long-term complications after Mustard atrial switch operation in patients with d-transposition of the great arteries (d-TGA), but follow-up for these procedures has not been established. Four patients with d-TGA and previous Mustard operation underwent percutaneous placement of covered stents to relieve superior and inferior vena caval baffle obstructions and leaks. At 6 to 13 months, assessment with 16-slice spiral computed tomography identified stent patency as well as lead placement and visualization of additional devices.

Adult↗
PubMed2004

Rotational X-ray coronary angiography.

We designed and implemented a digital flat-panel-based rotational X-ray coronary angiography technique hypothesizing that luminal disease could be identified with less radiation exposure and contrast usage compared to conventional angiography. Individuals scheduled for diagnostic coronary angiography were prospectively enrolled. In addition to conventional acquisitions in standard planes, subjects underwent one additional left coronary artery (LCA) or right coronary artery (RCA) rotational (spin) acquisition using a predefined trajectory. Radiation exposure and contrast volume were recorded for each run. Seventy-five subjects were enrolled. When compared with standard five-view cine acquisition, LCA spin angiography with one cranial and one caudal run resulted in 34.38% +/- 13.65% less radiation, 18.98% +/- 4.97% less contrast, and comparable assessment of stenosis severity. One spin acquisition compared with three standard cine acquisitions for RCA angiography resulted in 59.31% +/- 29.07% lower radiation, no significant change in contrast, and comparable assessment of stenosis severity. Rotational X-ray coronary angiography provides comparable visualization of coronary anatomy compared with traditional nonrotational coronary angiography with significantly less radiation exposure and contrast volume.

Coronary Angiography↗
PubMed2004

Metastatic melanoma of the left ventricle: cardiac imaging in the diagnosis and surgical approach.

A mass lesion occupying the left ventricle was noted on a screening CT scan in a 42-year-old man with a history of malignant melanoma. Subsequent echocardiography and cardiac MR imaging provided further hemodynamic and anatomic characterization of the lesion. These studies were also essential in guiding the proper surgical approach to allow extensive resection of the large mass without disrupting cardiac structures and function. The unique clinical aspects of this case are the unusual location for a lone cardiac metastasis of melanoma and the asymptomatic presentation despite the large size of the tumor and its apparent obstruction of ventricular outflow. The clinical and imaging features of this patient's threatening cardiac lesion are presented.

Adult↗
PubMed2004

Elevated defibrillation threshold with venlafaxine therapy.

Depression is a common comorbidity in patients with heart failure or implantable cardioverter-defibrillators (ICDs). A 35-year-old woman with depression, nonischemic cardiomyopathy, and a history of cardiac arrest had an ICD implanted. During initial testing, the device failed to internally defibrillate the patient. Venlafaxine, an antidepressant with cardiac sodium channel blocking activity, was identified as a potential contributor to her elevated defibrillation threshold. After the venlafaxine was discontinued, the ICD was able to successfully internally defibrillate the patient. Clinicians should be aware of this potential adverse drug-device interaction. Further studies are needed to determine the clinical significance of venlafaxine therapy in patients with ICDs.

Adult↗
PubMed2002

Dobutamine stress magnetic resonance imaging.

Cardiovascular magnetic resonance imaging (CMR) provides superior imaging of cardiac structure and function that makes it a useful tool in the diagnosis of cardiovascular disease. The heart's response to stress has long been used as a diagnostic aid for identifying a cardiovascular etiology for patient symptoms or for cardiovascular risk stratification. Historically, this has been done with stress nuclear scintigraphy or echocardiography techniques. A distinct advantage of CMR over these modalities is greater image quality resulting in better test characteristics; this review summarizes the techniques and principles involved in dobutamine stress MRI.

Journal Article↗