New uses of CT scans extend beyond the heart
A newly improved technique for viewing the interior of the blood vessels located in the heart could possibly have applications in other vessels that transport blood to and from different parts of the body, says a new report.
The technique, known as multidetector computed tomography, or MDCT, is a type of medical imaging method created by computer processing. It involves a large number of 2-D X-ray images, taken about an axis of rotation, that are finally combined together by a computer processor to form a detailed 3-D image.
The final 3-D image can be used to view the interior of several places within the body, including the head, chest, heart, abdomen, pelvis and extremities.
An MDCT image of the interior of the heart can be combined with another technique called angiography to view the blood vessels that transport blood within the heart. These vessels are known as the coronary arteries.
Angiography involves the injection of a contrast dye into the blood that allows visualization of blood flow within the vessels. This is essential in locating blockages that can impede blood flow.
This technique has improved drastically since its first use more than 30 years ago. The number of X-rays used for one image has increased from four to 64, leading to higher resolution images.
Also, more 2-D planes have become available to make the final 3-D image with the development of slip-ring technology in which the mechanism used to beam X-rays (called the gantry) constantly rotates around the patient to obtain multiple images.
Unfortunately, these advances come with some disadvantages - mainly long scan times. Longer periods of time spent in the CT scanner lead to larger doses of X-ray radiation in patients.
To counteract this, the speed of the gantry has increased so that the images can be taken more quickly. However there are limitations.
"At a gantry rotation speed of 300-350 ms, MDCT scanners are approaching current engineering limits for gravitational forces on the gantry," Karl Schuleri of Hopkins's Division of Cariology and one of the paper's authors, said. If the gantry is rotated any faster, the forces acting on it will be so massive that it will simply collapse from the effort needed to keep spinning.
The technique, known as multidetector computed tomography, or MDCT, is a type of medical imaging method created by computer processing. It involves a large number of 2-D X-ray images, taken about an axis of rotation, that are finally combined together by a computer processor to form a detailed 3-D image.
The final 3-D image can be used to view the interior of several places within the body, including the head, chest, heart, abdomen, pelvis and extremities.
An MDCT image of the interior of the heart can be combined with another technique called angiography to view the blood vessels that transport blood within the heart. These vessels are known as the coronary arteries.
Angiography involves the injection of a contrast dye into the blood that allows visualization of blood flow within the vessels. This is essential in locating blockages that can impede blood flow.
This technique has improved drastically since its first use more than 30 years ago. The number of X-rays used for one image has increased from four to 64, leading to higher resolution images.
Also, more 2-D planes have become available to make the final 3-D image with the development of slip-ring technology in which the mechanism used to beam X-rays (called the gantry) constantly rotates around the patient to obtain multiple images.
Unfortunately, these advances come with some disadvantages - mainly long scan times. Longer periods of time spent in the CT scanner lead to larger doses of X-ray radiation in patients.
To counteract this, the speed of the gantry has increased so that the images can be taken more quickly. However there are limitations.
"At a gantry rotation speed of 300-350 ms, MDCT scanners are approaching current engineering limits for gravitational forces on the gantry," Karl Schuleri of Hopkins's Division of Cariology and one of the paper's authors, said. If the gantry is rotated any faster, the forces acting on it will be so massive that it will simply collapse from the effort needed to keep spinning.
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