Thanks to our Italian amici, Alessandro and Puccio for sending me this abstract this morning. This abstract is published in the Vasculab program for their 2011 conference in Italy, October 13-14
http://www.vasculab.it/hemodyn2011/panel/sh/SH_ManciniM_The%20Cerebral%20Circulation%20Time%20in%20the%20evaluation%20of%20neurological%20diseases.pdf
I'll include the paper in Italics, and breakdown the research--
auth: Marcello Mancini presauth: Marcello Mancini institutions: Institute of Biostructure and Bioimaging National Council of Research Naples
The Cerebral Circulation Time in the evaluation of neurological diseases
abstract: Background -Recent newly developed ultrasound techniques extend our ability to study the cerebral hemodynamics in patients with neurological disease beyond the conventional blood flow velocity analysis. Different ultrasound methods are currently under investigation that either qualitatively or quantitatively describe brain perfusion.
-New technical advances have made it possible to see how long it takes blood to come and then go out of the brain.
The most widely used technique is bolus kinetics. After applying a ultrasound contrast agent bolus, time intensity curves of the wash-in and wash-out phase of the bolus passage through the brain are registered by imaging at a set frame rate and analyzing the ultrasound intensity in a given region of interest. Based on the time intensity curves, different parameters can be extracted such as peak intensity, time to peak, mean transit time, and incremental time (Fig1).
-This new technique, bolus kinetics, uses injected contrast dye to help the researches time how long it takes blood to flow. The contrast provdides a "marker" the researchers can see.
These parameters can be displayed in a tissue region of interest defined by the examiner. Studies based on histopathological techniques and on MR imaging demonstrate hypoxia-like brain tissue injury or thrombosis of small veins in patients with Multiple Sclerosis (MS).
-Readers of this page know we've been discussing hypoxic injury to brain tissue (from lack of oxygen) in research papers from Lassman to present day. The thrombosis (or timy clots) in small veins has also been shown as microvascular abnormalities on MRI by researchers like Ge.
Applying dynamic susceptibility contrast Magnetic Resonance Imaging, cerebral mean transit time values were found to be significantly prolonged in MS patients. We present the application of contrast enhanced ultrasound (CEUS) to assess global cerebral circulation time (CCT) in patients with multiple sclerosis (MS). The method is based on the assumption that the time required by an ultrasound contrast agent to pass from the cerebral arteries to the veins should be prolonged in patients with vessel disorders.
-This explains how the researchers measure mean transit time values, or the time it takes blood to travel. They are using contrast agent with ultrasound (CEUS) rather than the usual MRI, since doppler can follow FLOW, it's not a static picture. They time the contrast agent from it's departure in the carotid artery, til it's arrival at the jugular vein....
Here's what they did, and what it showed:
Methods We performed CEUS in 82 patients with MS, and 37 controls. The clinical diagnosis was established by neurological evaluation and neuroimaging findings. Impairment was assessed by the EDSS Scale.
Cerebral Circulation Time was defined as the time difference of ultrasound contrast bolus arrival between the carotid artery and internal jugular vein.
Results The MS patients were comparable to control subjects for age, sex, systolic and diastolic blood pressure and heart rate. The artery arrival time was similar in MS group and controls.
The longest and average Cerebral Circulation Times (CCTL,CCTM) were substantially prolonged in patients with MS compared with controls [CCTL MS patients: median (range) 6.5 sec. (3.3-29.2); controls 5.2 (2.57-7.63; p5.8 sec. (2.6-17.5); controls 4.7 (2.5-7.1); p
Conclusions Compared with the healthy control group, MS patients showed a significant prolongation of CCT. Our results suggest that a microvascular or venous outflow impairment could be associated with MS. The CEUS measurement of CCT may be useful tool to disclose cerebral microcirculatory dysfunction in MS patients.
It took 20-25% longer for the blood to travel in pwMS. This CEUS method is another means of measuring the transit time of blood thru the MS brain. And it is showing a difference from normals.
thanks to our Italian amici!
Joan
