Gd-DPTA as a MRI contrast Agent
Download
Report
Transcript Gd-DPTA as a MRI contrast Agent
Gd-DTPA as an MRI
Contrast Agent
Lindsay Dods
April 6, 2010
Supervisors: Robert Ta, Masters Student
Robert Bartha, Ph.D.
Introduction
MRI – Magnetic Resonance Imaging
Contrast Agents
Can be used to detect anatomical
structures and function.
Can enhance the contrast of an MRI
image, allowing for increased
differentiation.
Novel Contrast Agents must be
tested
Objectives
Show the effectiveness of Gd-DTPA
(Magnevist) as a contrast agent in
high field MRI.
As this agent is known to be
effective, the true objective is to
assess the testing protocol before
using novel contrast agents.
Approach
Compare contrast in mice brains
before and after incubation in contrast
agent
different incubation times.
Contrast is ratio of mean signal
intensity of the brain compared to
control
Hypothesis
The mean signal intensity of the
brain will increase with the addition
of contrast agent
This signal intensity will continue to
increase over time, until a
saturation point is reached
Intensity of the control is to remain
constant.
Methods
Prepare Samples
Split fixed brain
into two
hemispheres
Incubate one side
of the brain in
diluted Gd-DTPA,
use other side as
control
Methods
Scan
Perform T1 and T2
waited scans with a
9.4 T MRI.
Measure mean grey
level of each
hemisphere from
select slices in
ImageJ
Calculate Contrast
Results
Day 1, T2
Day 6, T2
Results
T1 - Contast over Tim e
2.5
Contrast
2
1.5
1
0.5
0
0
1
2
3
4
5
6
Tim e (Days)
Using Regression Analysis, P<0.05, therefore
result is significant.
7
Results
T2 Contrast Over Tim e
1.6
1.4
Contrast
1.2
1
0.8
0.6
0.4
0.2
0
0
1
2
3
4
5
6
Tim e (Days)
Using Regression Analysis, P<0.05, therefore
result is significant.
7
Discussion
Results aren’t as expected
Paramagnetic contrast agents alter
signal intensity by shortening
relaxation time of protons
Increase in signal intensity is
beneficial
Future Work
Contrast agent in disease diagnosis
Use this protocol on novel contrast
agents
Conclusion
Results were not conclusive to show
that signal intensity increased over
time with the addition of a contrast
agent.
More samples are needed to
determine if this protocol is an
effective way to test contrast
agents.