Related Experiment Video
Updated: Jan 29, 2026
11:53
Quantitative Proteomics Using Reductive Dimethylation for Stable Isotope Labeling
Published on: July 1, 2014
16.8K
Absolute quantitative MR perfusion and comparison against stable-isotope microspheres.
Yong I Jeong1, Gregory A Christoforidis2, Niloufar Saadat2
1Department of Biomedical Engineering, Northwestern University, Evanston, Illinois.
Magnetic Resonance in Medicine
|February 10, 2019
Summary
Quantitative MRI accurately measures cerebral blood flow (CBF) and cerebrovascular reactivity in canines. Adjustments for contrast bolus delay significantly enhance accuracy in ischemic conditions.
Area of Science:
- Neuroimaging
- Cerebrovascular Physiology
- Medical Physics
Background:
- Cerebral blood flow (CBF) is a critical indicator of brain health.
- Accurate measurement of CBF is essential for diagnosing and monitoring neurological conditions.
- Quantitative MRI offers a non-invasive method for assessing CBF.
Purpose of the Study:
- To validate a quantitative T1-bookend dynamic susceptibility contrast MRI perfusion protocol for absolute CBF measurement.
- To compare MRI-derived CBF with the gold standard stable-isotope neutron capture microsphere method.
- To assess performance under normocapnia, hypercapnia, and acute stroke conditions.
Main Methods:
- Anesthetized canines underwent serial MRI and microsphere measurements over two days.
- Physiological challenges included carbogen inhalation (hypercapnia) and middle cerebral artery occlusion (stroke model).
- CBF and cerebrovascular reactivity were compared between MRI and microspheres.
Main Results:
- Strong hemispheric correlations were observed between MRI and microspheres for CBF (r²=0.96) and cerebrovascular reactivity (r²=0.84) under normo- and hypercapnic states.
- Correction for contrast bolus delay and dispersion significantly improved MRI accuracy in the ischemic state (r²=0.96).
- Moderate correlations were found at the regional level.
Conclusions:
- MRI-based quantitative CBF provides moderate to strong correlations with the microsphere reference standard in a canine model.
- Contrast bolus delay and dispersion correction is crucial for accurate quantitative CBF assessment in focal ischemia.
- This MRI technique shows promise for evaluating cerebrovascular function and stroke.
Related Concept Videos
01:12Isotopes
64.2K
Elements have a set number of protons that determines their atomic number (Z). For example, all atoms with eight protons are oxygen; however, the number of neutrons can vary for atoms of the same element. The sum of the number of protons and the number of neutrons is the mass number (A). Atoms with the same atomic number but different mass numbers are called isotopes. Elements can have multiple isotopes, for example, carbon-12, carbon-13, and carbon-14.
An element's atomic mass, or weight,...
An element's atomic mass, or weight,...
64.2K
02:31Elements: Chemical Symbols and Isotopes
125.8K
A chemical symbol is an abbreviation used to indicate an element or an atom of an element. For example, the symbol for mercury is Hg. The same symbol is used to indicate one atom of mercury (microscopic domain) or to label a container of many atoms of the element mercury (macroscopic domain).
Some symbols are derived from the common English name of the element; others are abbreviations of the name in another language — Latin, Greek or German. For example, the symbol for aluminum (common name)...
Some symbols are derived from the common English name of the element; others are abbreviations of the name in another language — Latin, Greek or German. For example, the symbol for aluminum (common name)...
125.8K
01:23Absolute Value Inequalities
333
The absolute value is a mathematical tool that represents the distance of a number from zero on the number line, regardless of its sign. In the context of inequalities, absolute value expressions help define a range of permissible values or boundaries for a variable. These inequalities are commonly used in scientific modeling and data interpretation, where variability within or beyond a certain threshold must be captured precisely.An absolute value inequality of the form ∣x∣ ≤...
333
01:13Mean Absolute Deviation
3.3K
The mean absolute deviation is also a measure of the variability of data in a sample. It is the absolute value of the average difference between the data values and the mean.
Let us consider a dataset containing the number of unsold cupcakes in five shops: 10, 15, 8, 7, and 10. Initially, calculate the sample mean. Then calculate the deviation, or the difference, between each data value and the mean. Next, the absolute values of these deviations are added and divided by the sample size to...
Let us consider a dataset containing the number of unsold cupcakes in five shops: 10, 15, 8, 7, and 10. Initially, calculate the sample mean. Then calculate the deviation, or the difference, between each data value and the mean. Next, the absolute values of these deviations are added and divided by the sample size to...
3.3K
01:28Isotopes and Radioisotopes
11.8K
In the early 1900s, English chemist Frederick Soddy realized that an element could have atoms with different masses that were chemically indistinguishable. These different types are called isotopes — atoms of the same element that differ in mass. Isotopes differ in mass because they have different numbers of neutrons but are chemically identical because they have the same number of protons. Soddy was awarded the Nobel Prize in Chemistry in 1921 for this discovery.
An isotope containing...
An isotope containing...
11.8K
02:57The Sense of Self: Reflected Self-Appraisal and Social Comparison
56.0K
According to Charles Cooley, we base our image on what we think other people see (Cooley 1902). We imagine how we must appear to others, then react to this speculation. We don certain clothes, prepare our hair in a particular manner, wear makeup, use cologne, and the like—all with the notion that our presentation of ourselves is going to affect how others perceive us. We expect a certain reaction, and, if lucky, we get the one we desire and feel good about it. But more than that, Cooley...
56.0K