Perfusion scanning

About: Perfusion scanning is a research topic. Over the lifetime, 9496 publications have been published within this topic receiving 223860 citations. The topic is also known as: perfusion imaging.

Intrapericardial delivery of fibroblast growth factor-2 induces neovascularization in a porcine model of chronic myocardial ischemia.

Abstract: Therapeutic angiogenesis is a novel approach to the treatment of myocardial ischemia based on the use of proangiogenic growth factors to induce the growth of new blood vessels to supply the myocardium at risk. This study was designed to assess the safety and efficacy of a single intrapericardial injection of basic fibroblast growth factor (FGF-2) in a porcine model of chronic myocardial ischemia. Yorkshire pigs underwent ameroid placement around the left circumflex coronary artery. At 3 weeks, animals were randomized to receive a single intrapericardial injection of either saline (n = 10), 3 mg of heparin (n = 9), 3 mg of heparin + 30 microgram of FGF-2 (n = 10), 200 microgram of FGF-2 (n = 10), or 2 mg of FGF-2 (n = 10). Coronary angiography, microsphere flow, magnetic resonance functional, and perfusion imaging were performed before and 4 weeks after treatment, at which time histologic analysis was also performed on 3 animals in each group. In ischemic pigs, FGF-2 treatment resulted in significant increases in left-to-left angiographic collaterals and left circumflex coronary artery blood flow. These benefits were accompanied by improvements in myocardial perfusion and function in the ischemic territory, as well as histologic evidence of increased myocardial vascularity without any adverse effects. Not one of these benefits was seen in saline- or heparin-treated ischemic animals. A single intrapericardial injection of FGF-2 in a porcine model of chronic myocardial ischemia results in functionally significant myocardial angiogenesis, without any adverse outcomes. This mode of FGF-2 administration may prove to be a useful therapeutic strategy for the treatment of patients with ischemic heart disease.

Diffusion-weighted imaging or computerized tomography perfusion assessment with clinical mismatch in the triage of wake up and late presenting strokes undergoing neurointervention with Trevo (DAWN) trial methods:

Abstract: Rationale Efficacy of mechanical thrombectomy for acute stroke due to large vessel occlusion initiated beyond 6 h of time last seen well has not been demonstrated in randomized trials. Aim To establish whether subjects considered to have substantial areas of salvageable brain based on age-adjusted clinical core mismatch who can undergo endovascular treatment within 6-24 h from time last seen well (TLSW) have better outcomes at three months compared to subjects treated with standard medical therapy alone. Age-adjusted clinical core mismatch is defined by age (≤80 or >80 years), baseline National Institutes of Health Stroke Scale (NIHSS) (10-20 or ≥21), and core size (0-20 cm3 in subjects older than 80 and, in subjects younger than 80, 0-30 cm3 with NIHSS 10-20 and 31-50 cm3 with NIHSS ≥21). Design Prospective, randomized, multicenter, Bayesian adaptive-enrichment, open label trial with blinded endpoint assessment. For the purpose of enrolment, ischemic core size will be evaluated by CT perfusion or magnetic resonance imaging-diffusion-weighted imaging measured by automated software (RAPID). Procedures Subjects with acute ischemic stroke due to computed tomography angiography- or magnetic resonance angiogram-proven arterial occlusion of the intracranial internal carotid and/or proximal middle cerebral artery (M1) with age-adjusted clinical core mismatch in whom treatment can be initiated between 6 and 24 h from TSLW are randomized in a 1:1 ratio to receive mechanical embolectomy with the Trevo device or medical management alone. Sequential interim analyses allowing adaptation of enrolment criteria or stopping new enrolment for futility or predicted success will occur in every 50 randomized patients starting at 150 to a maximum of 500 patients. Study outcomes The primary endpoint is the modified Rankin Scale score at 90 days. The primary safety outcome is stroke-related mortality at 90 days. Analysis The primary endpoint, expressed as a utility-weighted modified Rankin Scale score is analyzed using a Bayesian posterior probability with adjustment for ischemic core size. For regulatory reasons, a nested co-primary endpoint analysis was added consisting of the proportion of subjects with modified Rankin Scale 0-2 between the active and control groups also analyzed using a Bayesian model.

Brain perfusion is abnormal in cocaine-dependent polydrug users: a study using technetium-99m-HMPAO and ASPECT.

Abstract: Cocaine abuse is widespread and has been associated with serious neurovascular complications. We studied a group of cocaine-dependent polydrug users with 99mTc-HMPAO and high-resolution SPECT and compared their perfusion pattern to cerebral perfusion in a group of older control subjects. Sixteen of 18 cocaine-dependent polydrug users had abnormal perfusion characterized primarily as small focal defects involving inferoparietal, temporal, and anterofrontal cortex and basal ganglia. Psychometric testing was abnormal in all 18 cocaine-dependent subjects. No relation was found between the severity of SPECT abnormalities and mode of administration or frequency or length of cocaine use. All 15 older normal subjects had normal cerebral perfusion. While the focal perfusion abnormalities to the cortex and basal ganglia could be explained by the profound vasoconstrictor effects of cocaine, the combinational use of multiple substances including cannabis and alcohol may play a contributory role. This study documents the high incidence of functional brain abnormalities in cocaine-dependent chronic polydrug users without corresponding abnormalities on imaging studies of cerebral anatomy and morphology.

Comparison of instruments for investigation of microcirculatory blood flow and red blood cell concentration

Abstract: The use of laser Doppler perfusion imaging LDPI and laser speckle perfusion imaging LSPI is well known in the noninvasive investigation of microcirculatory blood flow. This work compares the two techniques with the recently developed tissue viability TiVi im- aging system, which is proposed as a useful tool to quantify red blood cell concentration in microcirculation. Three systems are evaluated with common skin tests such as the use of vasodilating and vasocon- stricting drugs methlynicotinate and clobetasol, respectively and a reactive hyperaemia maneuver using a sphygmomanometer. The de- vices investigated are the laser Doppler line scanner LDLS, the laser speckle perfusion imager FLPI—both from Moor Instruments Axminster, United Kingdom—and the TiVi imaging system Wheels- Bridge AB, Linkoping, Sweden. Both imaging and point scanning by the devices are used to quantify the provoked reactions. Perfusion images of vasodilatation and vasoconstriction are acquired with both LDLS and FLPI, while TiVi images are acquired with the TiVi imager. Time acquisitions of an averaged region of interest are acquired for temporal studies such as the reactive hyperaemia. In contrast to the change in perfusion over time with pressure, the TiVi imager shows a different response due its measurement of blood concentration rather than perfusion. The responses can be explained by physiological un- derstanding. Although the three devices sample different compart- ments of tissue, and output essentially different variables, comparisons can be seen between the three systems. The LDLS system proves to be suited to measurement of perfusion in deeper vessels, while FLPI and TiVi showed sensitivity to more superficial nutritional supply. LDLS and FLPI are insensitive to the action of the vasoconstrictor, while TiVi shows the clear boundaries of the reaction. Assessment of the reso- lution, penetration depth, and acquisition rate of each instrument show complimentary features that should be taken into account when choosing a system for a particular clinical measurement. © 2009 Society