Blood Flow Imaging (blood + flow_imaging)

Distribution by Scientific Domains
Medical Sciences100%

Selected Abstracts

Blood Flow Imaging,A New Angle-Independent Ultrasound Modality for the Visualization of Flow in Atrial Septal Defects in Children

ECHOCARDIOGRAPHY, Issue 9 2007
Siri Ann Nyrnes M.D.
Background: Color Doppler imaging (CDI) is the most applied method for evaluation of flow in atrial septal defects (ASD). A new real time ultrasound flow imaging modality called blood flow imaging (BFI) is able to visualize the blood flow in any direction of the image and is not limited by velocity aliasing. The method thereby overcomes the two limitations most often encountered in CDI. In this study we compared BFI with CDI for the visualization of interatrial blood flow in children. Methods: We studied ASD flow in 13 children using both CDI and BFI in the same examination. CDI and BFI cineloops were prepared off-line and both optimal and suboptimal (increased color artifacts) images were presented in random order to four observers. They were asked to range from 0,100 on a visual analogue scale how certain they were of interatrial blood flow. The CDI and BFI ratings were compared using the exact Wilcoxon signed rank test for paired samples. Results: All ASDs visualized with CDI were confirmed using BFI. Two of the observers ranked BFI as being significantly better than CDI when the images were optimized. When the images were suboptimal three of the observers rated BFI as being significantly better. Conclusions: This pilot study indicates that BFI improves the visualization of interatrial blood flow in children. To include BFI in the ordinary echocardiography examination is easy and not time consuming. The method may prove to be a useful supplement to CDI in ASD imaging. [source]

Noninvasive blood flow imaging for real-time feedback during laser therapy of port wine stain birthmarks

LASERS IN SURGERY AND MEDICINE, Issue 3 2008
Yu-Chih Huang MS
Abstract Background and Objectives During laser therapy of port wine stain (PWS) birthmarks, regions of persistent perfusion may exist. Immediate retreatment of such regions may improve PWS laser therapeutic outcome. To address this need, we propose use of laser speckle imaging (LSI) to provide real-time, quantitative feedback during laser surgery. Herein, we present in vitro and in vivo data collected with a clinic-based LSI instrument. Study Design/Materials and Methods Prior to clinical implementation, we first investigated three aspects of LSI deemed important for clinical imaging: (1) instrument depth of field (DOF); (2) effects of laser irradiance on speckle flow index (SFI) values; and (3) measurement repeatability. Clinical measurements were acquired from the lesions of PWS patients immediately prior to and after laser therapy at the Beckman Laser Institute. Results Our preclinical data suggest the following: (1) instrument DOF was ,1 cm; (2) quantitative flow characterization with LSI was practically unaffected at normalized irradiance values between 0.06 and 0.5; and (3) our LSI instrument was capable of highly reproducible SFI values. From our clinical measurements, we found that the relative difference between blood perfusion in PWS lesions and adjacent normal skin was highly variable. Based on SFI images, the perfusion of PWS skin is sometimes indistinguishable from that of adjacent normal skin. With laser therapy, we measured a global decrease in blood perfusion, and we frequently observed distinct regions of persistent perfusion. Conclusions Our results demonstrate the potential role of image-guided laser therapy of PWS birthmarks. LSI is a promising tool for noninvasive blood flow characterization during laser therapy due to its relative simplicity and low cost. Laser Surg. Med. 40:167,173, 2008. © 2008 Wiley-Liss, Inc. [source]

Cerebral white matter blood flow and arterial blood pressure in preterm infants

ACTA PAEDIATRICA, Issue 10 2010
Klaus Børch
Abstract It is generally assumed that one reason why white matter injury is common in preterm infants is the relatively poor vascular supply. Aim:, To examine whether blood flow to the white matter is relatively more reduced at low blood pressure than is blood flow to the brain as a whole. Methods:, Thirteen normoxic preterm infants had blood flow imaging on 16 occasions with single-photon emission computed tomography (SPECT) using 99Tc labelled hexa-methylpropylenamide oxime (HMPAO) as the tracer. Gestational age was 26,32 weeks. Transcutaneous carbon dioxide was between 4.7 and 8.5 kPa and mean arterial blood pressure between 22 and 55 mmHg. Results:, There was no statistically significant direct relation between white matter blood flow percentage and any of the variables. Using non-linear regression, however, assuming a plateau over a certain blood pressure threshold and a positive slope below this threshold, the relation to white matter flow percentage was statistically significant (p = 0.02). The threshold was 29 mmHg (95% confidence limits 26,33). Conclusion:, Our analysis supports the concept of periventricular white matter as selectively vulnerable to ischaemia during episodes of low blood pressure. [source]