Magnetic Resonance Imaging
307
certain physiological data. Especially in tumor location, the MRI and PET can identify malignant tumors from healthy tissue, although PET is known to have a slightly
better confidence rating in malignancy determination.
15.10 SUMMARY
MRI relies on the free movement of odd protons in a nucleus. MRI provides the highest resolution among all imaging modalities used for biomedical applications. The
use of deoxyhemoglobin as a marker is used in an imaging technique called BOLD
contrast imaging. This method is very useful in mapping brain activity and constitutes the fundamental idea of f MRI. MR images are often registered with images
captured with other modalities such as PET to provide the anatomical resolution
to the functional information of other modalities.
PROBLEMS
15.1 Read the image in file “p_15_1.jpg” and display the image. This is a dorsal
look of a frontal plane view of a chest MRI showing a section of the heart. The
heart is indicated by an arrow.
a. Improve the quality of the image using a high-boost filter.
b. Choose a convenient location in the region the heart and use seed growing
to find the outline of the heart.* Start with a seed in the center of the supposed structure of the heart.
15.2 Read the image in file “p_15_2.jpg” and show the image. This is a dorsal
look of a frontal plane view of the heart.* This image is taken from the same
patient during the same imaging session as “p_15_1.jpg,” approximately 7 mm
posterior.
a. U se seed growing to outline the bone structures in both images. Start with
a seed in the center of the supposed bone structure.
b. Select some tie points in the two images and register image “p_15_2.jpg”
with respect to image “p_15_1.jpg.”
15.3 Read the image in file “p_15_3.gif” and display it. The file contains MR
images of the spine from various angles and cross sections. †
a. Split the six images.
b. Use a high-boot filter to improve the quality of the images.
c. I n the two images where the spine and the vertebrae are most visible,
choose a seed point in the middle of the vertebrae for each disk to start the
region growing process.
d. Calculate the size of the gaps between the vertebrae in the same manner.
e. F ind the angle between the disks in the lower section of the image. The
vertebrae interdisk angle has important clinical applications for diagnosing
certain back problems and herniated disks.
* Courtesy of Dr. Godtfred Holmvang, posted on PhysioBank. http://www.physionet.org/physiobank/
† Courtesy of Philips Medical Systems.
307
certain physiological data. Especially in tumor location, the MRI and PET can identify malignant tumors from healthy tissue, although PET is known to have a slightly
better confidence rating in malignancy determination.
15.10 SUMMARY
MRI relies on the free movement of odd protons in a nucleus. MRI provides the highest resolution among all imaging modalities used for biomedical applications. The
use of deoxyhemoglobin as a marker is used in an imaging technique called BOLD
contrast imaging. This method is very useful in mapping brain activity and constitutes the fundamental idea of f MRI. MR images are often registered with images
captured with other modalities such as PET to provide the anatomical resolution
to the functional information of other modalities.
PROBLEMS
15.1 Read the image in file “p_15_1.jpg” and display the image. This is a dorsal
look of a frontal plane view of a chest MRI showing a section of the heart. The
heart is indicated by an arrow.
a. Improve the quality of the image using a high-boost filter.
b. Choose a convenient location in the region the heart and use seed growing
to find the outline of the heart.* Start with a seed in the center of the supposed structure of the heart.
15.2 Read the image in file “p_15_2.jpg” and show the image. This is a dorsal
look of a frontal plane view of the heart.* This image is taken from the same
patient during the same imaging session as “p_15_1.jpg,” approximately 7 mm
posterior.
a. U se seed growing to outline the bone structures in both images. Start with
a seed in the center of the supposed bone structure.
b. Select some tie points in the two images and register image “p_15_2.jpg”
with respect to image “p_15_1.jpg.”
15.3 Read the image in file “p_15_3.gif” and display it. The file contains MR
images of the spine from various angles and cross sections. †
a. Split the six images.
b. Use a high-boot filter to improve the quality of the images.
c. I n the two images where the spine and the vertebrae are most visible,
choose a seed point in the middle of the vertebrae for each disk to start the
region growing process.
d. Calculate the size of the gaps between the vertebrae in the same manner.
e. F ind the angle between the disks in the lower section of the image. The
vertebrae interdisk angle has important clinical applications for diagnosing
certain back problems and herniated disks.
* Courtesy of Dr. Godtfred Holmvang, posted on PhysioBank. http://www.physionet.org/physiobank/
† Courtesy of Philips Medical Systems.