The purpose of this study was to investigate the time course of development of collateral blood flow in an animal model of aortic coarctation. A juxtaductal aortic stenosis (model coarctation) was surgically created in five juvenile pigs. MRI was performed preoperatively, 1 to 2 days postoperatively, and 2 to 10 weeks postoperatively. Aortic blood flow was measured by velocity-encoded cine MR (VENC-MR). The percent change in aortic blood flow (delta BF) from proximal to distal descending thoracic aorta was calculated, and a multiple-comparison paired t test used to assess changes in delta BF over time. Invasive flow measurements were obtained in one animal before sacrifice using an ultrasonic probe. delta BF preoperatively was -2 +/- 8% (mean +/- SE). delta BF increased to 32 +/- 7% (mean +/- SE, P = .022) 2 days postoperatively and 55 +/- 19% (P = .032) 2 to 8 weeks postoperatively. Invasive measurements were in qualitative agreement with the VENC-MR data. VENC-MR is an accurate noninvasive method of measuring collateral blood flow in aortic coarctation. Recruitment and development of collateral flow pathways occur rapidly in an animal model.

Animals↗

PubMedDate not supplied

Color Doppler flow mapping in the ultrasound diagnosis of total anomalous pulmonary venous connection.

With color Doppler flow mapping (CFM), we studied 16 children with total anomalous pulmonary venous connection (TAPVC), which was confirmed at cardiac catheterization, surgery, or autopsy in all but one case. The drainage was supracardiac in nine children, cardiac in four, and infracardiac in three. Obstruction to pulmonary venous return was present in seven children. Increased variance, reflecting disturbed blood flow, as well as increased velocities and aliasing were present in all patients. In patients without obstruction turbulence was present in the right atrium and throughout the common pulmonary venous structures. In patients with obstruction a discrete site of increased turbulence and velocity was identified at the site of obstruction. CFM allows rapid differentiation between normal and abnormal venous and arterial structures in TAPVC. In patients suspected of having TAPVC with obstruction, CFM complemented by pulsed Doppler facilitates the determination of the site of obstruction. CFM allows a more rapid appreciation of the anatomy in TAPVC than can be achieved by two-dimensional imaging alone.

Blood Flow Velocity↗

PubMedDate not supplied

Opacification of falx and tentorium during cerebral angiography: preliminary report.

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Adult↗

PubMedDate not supplied

MRI of tracheal and esophageal compression following surgery for congenital heart disease.

OBJECTIVE: Magnetic resonance imaging has proven to be a useful diagnostic tool for the evaluation of various types of vascular rings and congenital heart disease. We report two cases showing the accuracy of MRI in detecting post-surgical complications in patients with these conditions. MATERIALS AND METHODS: The two cases reported here demonstrate the use of MRI to show the altered vascular anatomy and the mechanism of tracheal and/or esophageal compression. RESULTS: In the first case, MRI demonstrated narrowing of the right pulmonary artery due to a dilated and posteriorly displaced ascending aorta with residual coarctation, and esophageal compression by an aberrant left subclavian artery. In the second case, MRI demonstrated esophageal compression by a posteriorly displaced ascending aorta. CONCLUSION: We conclude that MRI is an effective noninvasive method for assessing the results and complications of surgical correction of aortic abnormalities.

Aorta↗