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Proximal Pulmonary Arteries (proximal + pulmonary_artery)

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Medical Sciences	100%

Selected Abstracts

Assessing normal pulse wave velocity in the proximal pulmonary arteries using transit time: A feasibility, repeatability, and observer reproducibility study by cardiovascular magnetic resonance

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2007
MRCP, William M. Bradlow BM
Abstract Purpose To calculate pulse wave velocity (PWV) in the proximal pulmonary arteries (PAs) by cardiovascular magnetic resonance (CMR) using the transit-time method, and address respiratory variation, repeatability, and observer reproducibility. Materials and Methods A 1.9-msec interleaved phase velocity sequence was repeated three times consecutively in 10 normal subjects. Pulse wave (PW) arrival times (ATs) were determined for the main and branch PAs. The PWV was calculated by dividing the path length traveled by the difference in ATs. Respiratory variation was considered by comparing acquisitions with and without respiratory gating. Results For navigated data the mean PWVs for the left PA (LPA) and right PA (RPA) were 2.09 ± 0.64 m/second and 2.33 ± 0.44 m/second, respectively. For non-navigated data the mean PWVs for the LPA and RPA were 2.14 ± 0.41 m/second and 2.31 ± 0.49 m/second, respectively. No statistically significant difference was found between respiratory non-navigated data and navigated data. Repeated on-table measurements were consistent (LPA non-navigated P = 0.95, RPA non-navigated P = 0.91, LPA navigated P = 0.96, RPA navigated P = 0.51). The coefficients of variation (CVs) were 12.2% and 12.5% for intra- and interobserver assessments, respectively. Conclusion One can measure PWV in the proximal PAs using transit-time in a reproducible manner without respiratory gating. J. Magn. Reson. Imaging 2007;25:974,981. © 2007 Wiley-Liss, Inc. [source]

Proximal pulmonary artery blood flow characteristics in healthy subjects measured in an upright posture using MRI: The effects of exercise and age,

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2005
Christopher P. Cheng PhD
Abstract Purpose To use MRI to quantify blood flow conditions in the proximal pulmonary arteries of healthy children and adults at rest and during exercise in an upright posture. Materials and Methods Cine phase-contrast MRI was used to calculate mean flow and reverse flow index (RFI) in the main (MPA), right (RPA), and left (LPA) pulmonary arteries in healthy children and adults in an open-MRI magnet equipped with an upright MRI-compatible ergometer. Results From rest to exercise (150% resting heart rate), blood flow (liters/minute/m2) increased in the RPA (1.4 ± 0.3 vs. 2.5 ± 0.4; P < 0.001), LPA (1.1 ± 0.3 vs. 2.2 ± 0.6; P < 0.001), and MPA (2.7 ± 0.5 vs. 4.9 ± 0.5; P < 0.001). RFI decreased in the LPA (0.040 ± 0.030 vs. 0.017 ± 0.018; P < 0.02) and MPA (0.025 ± 0.024 vs. 0.008 ± 0.007; P < 0.03). Adults experienced greater retrograde flow in the MPA than the children (0.042 ± 0.029 vs. 0.014 ± 0.012; P < 0.02). Conclusion It appears that at both rest and during exercise, in children and adults alike, RPA/LPA mean blood flow distribution is predominantly determined by distal vascular resistance, while retrograde flow is affected by proximal pulmonary bifurcation geometry. J. Magn. Reson. Imaging 2005;21:752,758. © 2005 Wiley-Liss, Inc. [source]

Intravascular ultrasound imaging of the pulmonary arteries in primary pulmonary hypertension

RESPIROLOGY, Issue 1 2000
Takaaki Nakamoto
Objective: Intravascular ultrasound has the unique ability to provide cross-sectional images of the arterial wall. This study examined intravascular ultrasound (IVUS) images of the proximal pulmonary arteries in primary pulmonary hypertension (PPH). Methodology: Study 1: Specimens from four patients who had died of PPH (in vitro PPH group) were compared with those of three patients who had died of subarachnoid haemorrhage but had no evidence of cardiopulmonary disease (in vitro control group). Three-centimetre segments of the following levels were examined by IVUS: pulmonary trunk, eight secondary branch arteries of the upper, middle, and lower lobes of both lungs, and the thoracic descending aorta. Study 2: Four patients with PPH (in vivo PPH group) and five patients without pulmonary hypertension and no evidence of cardiopulmonary disease (in vivo control group) were examined. The IVUS images of the apical segmental artery of the right upper lobe and the descending branch of the right pulmonary artery were studied. Results: Echographic examination of formalin-fixed preparations of secondary branch sections of the pulmonary artery failed to show a clear three-layer structure in the in vitro control group (24 preparations), but a distinct three-layer structure and increased vessel wall thickness were observed in the in vitro PPH group (32 preparations). Similar findings were obtained in the in vivo study. The mean echo density of the proximal pulmonary arterial wall correlated well with the mean pulmonary arterial pressure (mPA) in the in vitro PPH, and also correlated with the mPA in the in vivo study (r = 0.960, P < 0.0001). The echo intensity of secondary branch sections of the pulmonary artery was higher in the in vitro PPH group than in the in vitro control group (180.5 ± 27.0 vs 132.5 ± 26.7 counts, P < 0.001); similar results were obtained in the in vivo study (144.7 ± 23.4 vs 85.0 ± 14.3 counts, P < 0.01). Conclusions: These results suggest that the histological changes detected in the pulmonary artery walls in the PPH group were responsible for the increased echo intensity. [source]