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.

Perfusion Computed Tomography in the Acute Phase of Mild Head Injury: Regional Dysfunction and Prognostic Value

Abstract: Objective: Traumatic brain injury is a major Cause of disability and death. Most patients sustain a mild head injury with a subgroup that experiences disabling symptoms interfering with return to work. Brain imaging in the acute phase is not predictive of outcome, as 20% of noncontrast computed tomographic (CT) scans on admission is normal in patients with a suboptimal Outcome. The aim of this study was to perform perfusion CT imaging in the acute phase of mild head injury in patients without intracranial abnormalities on the noncontrast CT, to assess whether these patients had cerebral perfusion abnormalities. Furthermore, the relation between perfusion CT parameters and severity of head injury and Outcome was evaluated. Methods: In patients with mild head injury and normal noncontrast CT, perfusion CT was performed directly after admission. The perfusion data were compared with data of 25 healthy control subjects. Outcome was determined 6 months after injury with the extended Glasgow Coma Outcome Scale score and return to work. Results: Seventy-six patients were included. In patients with a decreased Glasgow Coma Scale score, a significant decrease of cerebral blood flow and cerebral blood volume was detected in the frontal and occipital gray matter. In logistic regression analyses, decreased cerebral blood flow and cerebral blood volume in the Frontal lobes predicted worse outcome according to the extended Glasgow Coma Outcome Scale score. CT perfusion parameters did not predict return to work. Interpretation: In the acute phase of mild head injury, disturbed cerebral perfusion is seen in patients with normal noncontrast CT correlating with severity Of injury and Outcome. Ann Neurol 2009;66:809-816

Validation of minimally invasive measurement of myocardial perfusion using electron beam computed tomography and application in human volunteers.

Abstract: OBJECTIVES To measure myocardial perfusion using an estimate of intramyocardial vascular volume obtained by electron beam computed tomography (EBCT) in an animal model; to assess the feasibility and validity of measuring regional myocardial perfusion in human volunteers using the techniques developed and validated in the animal studies. METHODS Measurements of myocardial perfusion with EBCT employing intravenous contrast injections were compared with radioactive microsphere measurements (flow 57 to 346 ml/100 g/min) in seven closed chest dogs. Fourteen human volunteers then underwent EBCT scans using intravenous contrast injections. RESULTS Mean (SEM) global intramyocardial vascular volume by EBCT was 7.6 (1.1)%. The correlation between global EBCT (y) and microsphere (x) perfusion was y = 0.59x + 15.56 ( r = 0.86) before, and y = 0.72x + 6.06 ( r = 0.88) after correcting for intramyocardial vascular volume. Regional perfusion correlation was y = 0.75x + 23.84 ( r = 0.82). Corresponding improvements in agreement between the two techniques were also seen using Bland–Altman plots. In the human subjects, mean resting global myocardial flow was 98 (6) ml/100 g/min, with homogeneous flow across all regions. In 10 of these subjects, perfusion was studied during coronary vasodilatation using intravenous adenosine. Global flow increased from 93 (5) ml/100 g/min at rest to 250 (19) ml/100 g/min during adenosine (p < 0.001), with an average perfusion reserve ratio of 2.8 (0.2). Similar changes in regional perfusion were observed and were uniform throughout all regions, with a mean regional perfusion reserve ratio of 2.8 (0.3). CONCLUSIONS Accounting for intramyocardial vascular volume improves the accuracy of EBCT measurements of myocardial perfusion when using intravenous contrast injections. The feasibility of providing accurate measurements of global and regional myocardial perfusion and perfusion reserve in people using this minimally invasive technique has also been demonstrated.

Diffusion/perfusion MR imaging of the brain: from structure to function.

Abstract: 328 C ONSIDERABLE interest has recently emerged in the capability of magnetic resonance (MR) to image and measure molecular diffusion and capillary flow or perfusion. Sessions on diffusion/perfusion imaging are now common at major MR imaging meetings, and the number of publications related to this topic is rapidly growing. This interest has been triggered by the important clinical potential of diffusion/perfusion imaging and also by the controversies that still exist in its technical achievement, mainly regarding perfusion measurement. The excellent article by Chenevert et al (1) in this issue has the merit of addressing both issues. Diffusion/perfusion imaging relies on the well known sensitivity of MR to spin motion in the presence of magnetic field inhomogeneities. Motion thus represents a “natural” marker of the MR signal, so that no external contrast material is theoretically needed. In this respect, diffusion and perfusion are often confounded. Indeed, diffusion and perfusion refer to different physical phenomena and present different technical challenges. While perfusion can be better evaluated today by many methods excluding MR imaging, the choice of MR imaging to measure diffusion in vivo is almost a necessity. Measuring molecular diffusion in tissues presents several potentially useful approaches to tissue characterization for functional studies, from the determination of cell geometry to the early