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Warren J Manning

Publications and source records attributed to Warren J Manning.

83 records · Page 5Linked to original sources
PubMed2002

"Soap-Bubble" visualization and quantitative analysis of 3D coronary magnetic resonance angiograms.

In order to compare coronary magnetic resonance angiography (MRA) data obtained with different scanning methodologies, adequate visualization and presentation of the coronary MRA data need to be ensured. Furthermore, an objective quantitative comparison between images acquired with different scanning methods is desirable. To address this need, a software tool ("Soap-Bubble") that facilitates visualization and quantitative comparison of 3D volume targeted coronary MRA data was developed. In the present implementation, the user interactively specifies a curved subvolume (enclosed in the 3D coronary MRA data set) that closely encompasses the coronary arterial segments. With a 3D Delaunay triangulation and a parallel projection, this enables the simultaneous display of multiple coronary segments in one 2D representation. For objective quantitative analysis, frequently explored quantitative parameters such as signal-to-noise ratio (SNR); contrast-to-noise ratio (CNR); and vessel length, sharpness, and diameter can be assessed. The present tool supports visualization and objective, quantitative comparisons of coronary MRA data obtained with different scanning methods. The first results obtained in healthy adults and in patients with coronary artery disease are presented.

Adult↗
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

Apical hypertrophic cardiomyopathy: clinical, electrocardiographic, scintigraphic, echocardiographic, and magnetic resonance imaging findings of a case.

The apical variant of nonobstructive hypertrophic cardiomyopathy (HCM) constitutes a minority of all cases of HCM and generally carries a favorable clinical outcome. We describe a 68 year-old Caucasian woman who presented with exertional dyspnea. The patient underwent stress testing with electrocardiogram-gated single-photon emission computed tomography imaging and resting transthoracic echocardiography. The patient also underwent cardiac magnetic resonance imaging at rest, including conventional structural and functional imaging and cine complementary spatial modulation of magnetization-tagged imaging (CSPAMM). The noninvasive evaluation of the heart demonstrated apical hypertrophy with regional systolic dysfunction, establishing the diagnosis of apical HCM. This case suggests a potential value of CSPAMM in characterizing apical HCM.

Aged↗
PubMed2002

Coronary magnetic resonance angiography for assessment of the stent lumen: a phantom study.

PURPOSE: To evaluate the feasibility of visualizing the stent lumen using coronary magnetic resonance angiography in vitro. MATERIAL AND METHODS: Nineteen different coronary stents were implanted in plastic tubes with an inner diameter of 3 mm. The tubes were positioned in a plastic container filled with gel and included in a closed flow circuit (constant flow 18 cm/sec). The magnetic resonance images were obtained with a dual inversion fast spin-echo sequence. For intraluminal stent imaging, subtraction images were calculated from scans with and without flow. Subsequently, intraluminal signal properties were objectively assessed and compared. RESULTS: As a function of the stent type, various degrees of in-stent signal attenuation were observed. Tantalum stents demonstrated minimal intraluminal signal attenuation. For nitinol stents, the stent lumen could be identified, but the intraluminal signal was markedly reduced. Steel stents resulted in the most pronounced intraluminal signal voids. CONCLUSIONS: With the present technique, radiofrequency penetration into the stents is strongly influenced by the stent material. Thesefindings may have important implicationsforfuture stent design and stent imaging strategies.

Blood Vessel Prosthesis Implantation↗
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

Navigator-gated free-breathing three-dimensional balanced fast field echo (TrueFISP) coronary magnetic resonance angiography.

RATIONALE AND OBJECTIVES: Recent developments of MR imaging equipment enabled high-quality steady state-free-precession (Balanced FFE, True-FISP) MR-imaging with a substantial 'T2 like' contrast, resulting in a high signal intensity of the blood-pool without the application of exogenous contrast agents. It is hypothesized that Balanced-FFE may be valuable for contrast enhancement in 3D free-breathing coronary MRA. MATERIALS AND METHODS: Navigator-gated free-breathing cardiac triggered coronary MRA was performed in 10 healthy adult subjects and three patients with radiograph defined coronary artery disease using a segmented k-space 3D Balanced FFE imaging sequence. RESULTS: High contrast-to-noise ratio between the blood-pool and the myocardium (29 +/- 8) and long segment visualization of both coronary arteries could be obtained in about 5 minutes during free breathing using the present navigator-gated Balanced-FFE coronary MRA approach. First patient results demonstrated successful display of coronary artery stenoses. CONCLUSION: Balanced FFE offers a potential alternative for endogenous contrast enhancement in navigator-gated free-breathing 3D coronary MRA. The obtained results together with the relatively short scanning time warrant further studies in larger patient collectives.

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↗