Biomedical subjects

Kraig V Kissinger

Publications and source records attributed to Kraig V Kissinger.

13 recordsLinked to original sources

PubMed2003

Comparison of aortic elasticity determined by cardiovascular magnetic resonance imaging in obese versus lean adults.

The vascular properties of large vessels in the obese have not been adequately studied. We used cardiovascular magnetic resonance imaging to quantify the cross-sectional area and elastic properties of the ascending thoracic and abdominal aorta in 21 clinically healthy obese young adult men and 25 men who were age-matched lean controls. Obese subjects had greater maximal cross-sectional area of the ascending thoracic aorta (984 +/- 252 vs 786 +/- 109 mm(2), p <0.01) and of the abdominal aorta (415 +/- 71 vs 374 +/- 51 mm(2), p <0.05). When indexed for height the differences persisted, but when indexed for body surface area, a significant difference between groups was found only for the maximal abdominal aortic cross-sectional area. The obese subjects also had decreased abdominal aortic elasticity, characterized by 24% lower compliance (0.0017 +/- 0.0004 vs 0.0021 +/- 0.0005 mm(2)/kPa/mm, p <0.01), 22% higher stiffness index beta (6.0 +/- 1.5 vs 4.9 +/- 0.7, p <0.005), and 41% greater pressure-strain elastic modulus (72 +/- 25 vs 51 +/- 9, p <0.005). At the ascending thoracic aorta, only the pressure-strain elastic modulus was different between obese and lean subjects (85 +/- 42 vs 65 +/- 26 kPa, respectively; p <0.05), corresponding to a 31% difference-but arterial compliance and stiffness index were not significantly different between groups. In clinically healthy young adult obese men, obesity is associated with increased cross-sectional aortic area and decreased aortic elasticity.

Adult↗

PubMed2003

Coronary MR angiography clinical applications and potential for imaging coronary artery disease.

Over the past decade, CMRA has emerged as a unique clinical imaging tool with applications in selected populations. Patients with suspected coronary artery anomalies and patients with Kawasaki disease and coronary aneurysms are among those for whom CMRA has demonstrated clinical usefulness. For assessment of patients with atherosclerotic CAD, CMRA is useful for detection of patency of bypass grafts. At centers with appropriate expertise and resources, CMRA also appears to be of value for exclusion of severe proximal multivessel CAD in selected patients. Data from multicenter trials will continue to define the clinical role of CMRA, particularly as it relates to assessment of CAD. Future developments and enhancements of CMRA promise better lumen and coronary artery wall imaging. This may become the new target in noninvasive evaluation of CAD.

Coronary Disease↗

PubMed2003

Cardiac structure and function in the obese: a cardiovascular magnetic resonance imaging study.

BACKGROUND: Obesity is a major health problem in the Western world. Among obese subjects cardiac pathology is common, but conventional noninvasive imaging modalities are often suboptimal for detailed evaluation of cardiac structure and function. We investigated whether cardiovascular magnetic resonance imaging (CMR) can better characterize possible cardiac abnormalities associated with obesity, in the absence of other confounding comorbidities. METHODS: In this prospective cross-sectional study, CMR was used to quantify left and right ventricular volumes, ejection fraction, mass, cardiac output, and apical left ventricular rotation in 25 clinically healthy obese men and 25 age-matched lean controls. RESULTS: Obese subjects had higher left ventricular mass (203 +/- 38 g vs. 163 +/- 22 g, p < 0.001), end-diastolic volume (176 +/- 29 mL vs. 156 +/- 25 mL, p < 0.05), and cardiac output (8.2 +/- 1.2 L/min vs. 6.4 +/- 1.3 L/min, p < 0.001). The obese also had increased right ventricular mass (105 +/- 25 g vs. 87 +/- 18 g, p < 0.005) and end-diastolic volume (179 +/- 36 mL vs. 155 +/- 28 mL, p < 0.05). When indexed for height, differences in left and right ventricular mass, and left ventricular end-diastolic volume remained significant. Apical left ventricular rotation and rotational velocity patterns were also different between obese and lean subjects. CONCLUSIONS: Obesity is independently associated with remodeling of the heart. Cardiovascular magnetic resonance imaging identifies subtle cardiac abnormalities and may be the preferred imaging technique to evaluate cardiac structure and function in the obese.

Adult↗

PubMed2002

Three-dimensional black-blood cardiac magnetic resonance coronary vessel wall imaging detects positive arterial remodeling in patients with nonsignificant coronary artery disease.

BACKGROUND: Direct noninvasive visualization of the coronary vessel wall may enhance risk stratification by quantifying subclinical coronary atherosclerotic plaque burden. We sought to evaluate high-resolution black-blood 3D cardiovascular magnetic resonance (CMR) imaging for in vivo visualization of the proximal coronary artery vessel wall. METHODS AND RESULTS: Twelve adult subjects, including 6 clinically healthy subjects and 6 patients with nonsignificant coronary artery disease (10% to 50% x-ray angiographic diameter reduction) were studied with the use of a commercial 1.5 Tesla CMR scanner. Free-breathing 3D coronary vessel wall imaging was performed along the major axis of the right coronary artery with isotropic spatial resolution (1.0x1.0x1.0 mm(3)) with the use of a black-blood spiral image acquisition. The proximal vessel wall thickness and luminal diameter were objectively determined with an automated edge detection tool. The 3D CMR vessel wall scans allowed for visualization of the contiguous proximal right coronary artery in all subjects. Both mean vessel wall thickness (1.7+/-0.3 versus 1.0+/-0.2 mm) and wall area (25.4+/-6.9 versus 11.5+/-5.2 mm(2)) were significantly increased in the patients compared with the healthy subjects (both P<0.01). The lumen diameter (3.6+/-0.7 versus 3.4+/-0.5 mm, P=0.47) and lumen area (8.9+/-3.4 versus 7.9+/-3.5 mm(2), P=0.47) were similar in both groups. CONCLUSIONS: Free-breathing 3D black-blood coronary CMR with isotropic resolution identified an increased coronary vessel wall thickness with preservation of lumen size in patients with nonsignificant coronary artery disease, consistent with a "Glagov-type" outward arterial remodeling. This novel approach has the potential to quantify subclinical disease.

Adult↗

PubMed2002

Age and sex distribution of subclinical aortic atherosclerosis: a magnetic resonance imaging examination of the Framingham Heart Study.

Autopsy data demonstrate a correlation between subclinical aortic atherosclerosis and cardiovascular disease. Therefore, noninvasive cardiovascular magnetic resonance (CMR) of subclinical atherosclerosis may provide a novel measure of cardiovascular risk, but it has not been applied to an asymptomatic population-based cohort to establish age- and sex-specific normative data. Participants in the Framingham Heart Study offspring cohort who were free of clinically apparent coronary disease were randomly sampled from strata of sex, quartiles of age, and quintiles of Framingham Coronary Risk Score. Subjects (n=318, aged 60+/-9 years, range 36 to 78 years, 51% women) underwent ECG-gated T2-weighted black-blood thoracoabdominal aortic CMR scanning. CMR evidence of aortic atherosclerosis was noted in 38% of the women and 41% of the men. Plaque prevalence and all measures of plaque burden increased with age group and were greater in the abdomen than in the thorax for both sexes and across all age groups. In addition, the Framingham Coronary Risk Score was significantly correlated with all plaque prevalence and burden measures for women but only for men after age adjustment. These noninvasive CMR data extend the prior autopsy-based prevalence estimates of subclinical atherosclerosis and may help to lay the foundation for future studies of risk stratification and treatment of affected individuals.

Adult↗

PubMed2002

Gender differences and normal left ventricular anatomy in an adult population free of hypertension. A cardiovascular magnetic resonance study of the Framingham Heart Study Offspring cohort.

OBJECTIVES: We sought to derive gender-specific cardiovascular magnetic resonance (CMR) reference values for normative left ventricular (LV) anatomy and function in a healthy adult population of clinically relevant age. BACKGROUND: Cardiovascular magnetic resonance imaging is increasingly applied in the clinical setting, but age-relevant, gender-specific normative values are currently unavailable. METHODS: A representative sample of 318 Framingham Heart Study (FHS) Offspring participants free of clinically overt cardiovascular disease underwent CMR examination to determine LV end-diastolic and end-systolic volume (EDV and ESV, respectively), mass, ejection fraction (EF) and linear dimensions (wall thickness, cavity length). Subjects with a clinical history of hypertension or those with a systolic blood pressure > or =140 mm Hg or diastolic pressure > or =90 mm Hg at any FHS cycle examination were excluded, leaving 142 subjects (63 men, 79 women; age 57 +/- 9 years). RESULTS: All volumetric (EDV, ESV, mass) and unidimensional measures were significantly greater (p < 0.001) in men than in women and remained greater (p < 0.02) after adjustment for subject height. Volumetric measures were greater (p < 0.001) in men than in women after adjustment for body surface area (BSA), but there were increased linear dimensions in women after adjustment for BSA. In particular, end-diastolic dimension indexed to BSA was greater in women (p < 0.001) than in men. There were no gender differences in global LVEF (men = 0.69; women = 0.70). CONCLUSIONS: Cardiovascular magnetic resonance measures of LV volumes, mass and linear dimensions differ significantly according to gender and body size. This study provides gender-specific normal CMR reference values, uniquely derived from a population-based sample of persons free of cardiovascular disease and clinical hypertension. These data may serve as a reference to identify LV pathology in the adult population.

Adult↗

PubMed2002

Coronary magnetic resonance angiography in adolescents and young adults with kawasaki disease.

BACKGROUND: In patients with Kawasaki disease, serial evaluation of the distribution and size of coronary artery aneurysms (CAA) is necessary for risk stratification and therapeutic management. Although transthoracic echocardiography is often sufficient for this purpose initially, visualization of the coronary arteries becomes progressively more difficult as children grow. We sought to prospectively compare coronary magnetic resonance angiography (MRA) and x-ray coronary angiography findings in patients with CAA caused by Kawasaki disease. METHODS AND RESULTS: Six subjects (age 10 to 25 years) with known CAA from Kawasaki disease underwent coronary MRA using a free-breathing T2-prepared 3D bright blood segmented k-space gradient echo sequence with navigator gating and tracking. All patients underwent x-ray coronary angiography within a median of 75 days (range, 1 to 359 days) of coronary MRA. There was complete agreement between MRA and x-ray angiography in the detection of CAA (n=11), coronary artery stenoses (n=2), and coronary occlusions (n=2). Excellent agreement was found between the 2 techniques for detection of CAA maximal diameter (mean difference=0.4 +/- 0.6 mm) and length (mean difference=1.4 +/- 1.6 mm). The 2 methods showed very similar results for proximal coronary artery diameter (mean difference=0.2 +/- 0.5 mm) and CAA distance from the ostia (mean difference=0.1 +/- 1.5 mm). CONCLUSION: Free-breathing 3D coronary MRA accurately defines CAA in patients with Kawasaki disease. This technique may provide a non-invasive alternative when transthoracic echocardiography image quality is insufficient, thereby reducing the need for serial x-ray coronary angiography in this patient group.

Adolescent↗

PubMed2002

Comparison of fat suppression strategies in 3D spiral coronary magnetic resonance angiography.

PURPOSE: In the present study, the impact of the two different fat suppression techniques was investigated for free breathing 3D spiral coronary magnetic resonance angiography (MRA). As the coronary arteries are embedded in epicardial fat and are adjacent to myocardial tissue, magnetization preparation such as T(2)-preparation and fat suppression is essential for coronary discrimination. MATERIALS AND METHODS: Fat-signal suppression in three-dimensional (3D) thin- slab coronary MRA based on a spiral k-space data acquisition can either be achieved by signal pre-saturation using a spectrally selective inversion recovery pre-pulse or by spectral-spatial excitation. In the present study, the performance of the two different approaches was studied in healthy subjects. RESULTS: No significant objective or subjective difference was found between the two fat suppression approaches. CONCLUSION: Spectral pre-saturation seems preferred for coronary MRA applications due to the ease of implementation and the shorter cardiac acquisition window.

Adult↗

PubMed2002

Impact of navigator timing on free-breathing submillimeter 3D coronary magnetic resonance angiography.

The purpose of this study was to investigate the impact of navigator timing on image quality in navigator-gated and real-time motion-corrected, free-breathing, three-dimensional (3D) coronary MR angiography (MRA) with submillimeter spatial image resolution. Both phantom and in vivo investigations were performed. 3D coronary MRA with real-time navigator technology was applied using variable navigator time delays (time delay between the navigator and imaging sequences) and varying spatial resolutions. Quantitative objective and subjective image quality parameters were assessed. For high-resolution imaging, reduced image quality was found as a function of increasing navigator time delay. Lower spatial resolution coronary MRA showed only minor sensitivity to navigator timing. These findings were consistent among volunteers and phantom experiments. In conclusion, for submillimeter navigator-gated and real-time motion-corrected 3D coronary MRA, shortening the time delay between the navigator and the imaging portion of the sequence becomes increasingly important for improved spatial resolution.

Coronary Disease↗

PubMed2002

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

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 cm3, range 4.2-119.1 cm3). In all subjects, inspiratory breathholding decreased irradiated cardiac volume [median change: -18.1 cm3 (-49%), p < or = 0.001 vs. ETid]. In 21% of patients, the entire heart could be displaced outside the radiation field with deep inspiration. Age was not correlated with change or percentage change in cardiac volume with respiratory maneuvers. We conclude that in breast cancer patients, deep inspiratory maneuvers significantly decrease irradiated cardiac volume included in the left breast radiation field. Such an approach during delivery of radiation therapy allows preservation of radiation dosage to the breast, while reducing cardiac involvement and possible associated cardiovascular toxicity.

Adult↗

PubMed2002

Myocardial drug distribution pattern following intrapericardial delivery: an MRI analysis.

OBJECTIVES: The main goal was to gain insights into the pharmacokinetics of intrapericardial drug delivery using magnetic resonance (MR) imaging analysis and the extracellular MR contrast agent gadopentetate dimeglumine (Gd-DTPA) as a model. BACKGROUND: Recent development of catheter-based techniques to access the intact pericardial space has increased interest in intrapericardial delivery for local cardiac therapy. Distribution and myocardial penetration of intrapericardial agents are not well characterized. METHODS: The intact pericardial space was percutaneously accessed through the right atrial appendage in ten anesthetized pigs, following which 5 mL Gd-DTPA (N = 8) or normal saline as control (N = 2) were administered. Animals were sacrificed at 1, 3, 3.5, 5, or 8 hr. The whole heart was excised, washed with normal saline, and the chambers distended with saline-filled bags. Myocardial penetration of Gd-DTPA was analyzed by a series of short-axis T1-weighted turbospin-echo MR images. RESULTS: At 1, 3, and 3.5 hr after Gd-DTPA, a uniform ring of enhancement was found along the epicardium, with a depth density related to time after administration. No contrast ring was visible at 5 or 8 hr or in control animals. Transmural myocardial T1 values obtained 5 hr after Gd-DTPA administration were reduced, suggesting that Gd-DTPA had penetrated uniformly throughout the myocardium. CONCLUSIONS: Intrapericardial administration results in relatively uniform distribution of an agent across the ventricular epicardium. The depth of penetration is consistent with functional evidence that epicardial structures can be targeted by this technique.

Animals↗

PubMed2002

Real-time motion correction in navigator-gated free-breathing double-oblique submillimeter 3D right coronary artery magnetic resonance angiography.

RATIONALE AND OBJECTIVES: The purpose of this study was the investigation of the impact of real-time adaptive motion correction on image quality in navigator-gated, free-breathing, double-oblique three-dimensional (3D) submillimeter right coronary magnetic resonance angiography (MRA). MATERIALS AND METHODS: Free-breathing 3D right coronary MRA with real-time navigator technology was performed in 10 healthy adult subjects with an in-plane spatial resolution of 700 x 700 microm. Identical double-oblique coronary MR-angiograms were performed with navigator gating alone and combined navigator gating and real-time adaptive motion correction. Quantitative objective parameters of contrast-to-noise ratio (CNR) and vessel sharpness and subjective image quality scores were compared. RESULTS: Superior vessel sharpness, increased CNR, and superior image quality scores were found with combined navigator gating and real-time adaptive motion correction (vs. navigator gating alone; P < 0.01 for all comparisons). CONCLUSION: Real-time adaptive motion correction objectively and subjectively improves image quality in 3D navigator-gated free-breathing double-oblique submillimeter right coronary MRA.

Adult↗

PubMed2002

Renal arteries: navigator-gated balanced fast field-echo projection MR angiography with aortic spin labeling: initial experience.

A cardiac-triggered free-breathing three-dimensional balanced fast field-echo projection magnetic resonance (MR) angiographic sequence with a two-dimensional pencil-beam aortic labeling pulse was developed for the renal arteries. For data acquisition during free breathing in eight healthy adults and seven consecutive patients with renal artery disease, real-time navigator technology was implemented. This technique allows high-spatial-resolution and high-contrast renal MR angiography and visualization of renal artery stenosis without exogenous contrast agent or breath hold. Initial promising results warrant larger clinical studies.

Adult↗