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Free-breathing magnetic resonance imaging of the liver

Imagine that you just arrived at the radiology department to have a magnetic resonance imaging (MRI) scan of the abdomen. Many abdominal MR scans require breath holds to acquire an adequate amount of data to produce excellent quality images.1 This would be easy for most healthy patients, even for the 15 seconds may be necessary. Now, image you are in the same situation, but it is after you have recently had abdominal surgery. How long do you think you could hold your breath? You may be able to hold it for a short period of time, but it might be incredibly difficult to hold for an extended period of time.

MRI and the liver

Traditional MRI can be used to image blood vessels, ducts, and hepatic (liver) tissues, even without contrast.2 MRI provides a way to image organ and tissue structures within the body without ionizing radiation, which is used in both CT and X-ray. MR can also show information about bile duct abnormalities, such as kidney stones. In some studies, MRI with a specific liver-targeting contrast has been shown to have a higher sensitivity than contrast-enhanced CT.3

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The free-breathing solution

Patients who are dealing with side effects of cancer treatments, who are injured or who have extensive disease damage in the abdomen may have trouble. This can make the study insufficient for analysis by the radiologist. Companies that create magnetic resonance software have been working on a solution that does not require breath-holds and utilizes motion-correction to reduce artifacts. One technique utilizes automated tracker placement that helps to combat respiratory motion. This particular program is compatible with many useful sequences, such as T2-weighted, fast spin echo (FSE) and diffusion-weighted imaging (DWI) sequences.1

The tracker monitors and synchronizes with the patient's breathing pattern, which could reduce respiratory ghosting artifacts.1 Artifacts are created by noise or motion during the MRI scan, and they can interfere with the image. They may appear as a blurriness or distortion. Combining this technique with some others can lead to excellent image quality with a free-breathing scan without sacrificing resolution, especially if the other technique aims to increase resolution.

One study allowed for the imaging of a 70-year-old man who could not hold his breath for longer than seven seconds.1 This scan may have provided information about his liver disease that was unobtainable without these techniques. the scan showed additional lesions that were not being improved during treatment. The desired scan may deliver not only this type of important information, but also quantitative values through a simplified prescription, high spatial and temporal resolution. This may also help to reduce the worry from a radiologist about improperly timed contrast-enhancement.

With the information that can be obtained by MRI, physicians may be able to observe the effects of disease and the response of treatments. In some cases, like that of the 70-year-old, this information cannot be obtained with the traditional methods that require breath-holding. A free-breathing technique for MRI could be the solution to this problem. The technique described above, with its automated tracker, may allow for imaging with high spatial and temporal resolution, leading to high quality images for clinical analysis.

For more information, please read SIGNA Pulse "Free-breathing liver imaging using DISCO with Auto Navigator."

References

1. Claire Moisson and Stephanie Sellie. "Free-breathing liver imaging using DISCO with Auto Navigator." SIGNA Pulse. Spring 2019. Web. 16 May 2019. <http://www.gesignapulse.com/signapulse/spring_2019/MobilePagedReplica.action?pm=1&folio=66#pg66>.

2. Nicholas T. Orfanidis. "Imaging Tests of the Liver and Gallbladder." MerckManuals.com. March 2017. Web. 21 May 2019. <https://www.merckmanuals.com/professional/hepatic-and-biliary-disorders/testing-for-hepatic-and-biliary-disorders/imaging-tests-of-the-liver-and-gallbladder>.

3. Maria Raquel Oliva and Sanjay Saini. "Liver cancer imaging: role of CT, MRI, US and PET." Cancer Imaging. 2 April 2004; 4(Spec No A): S42-S46. Web. 21 May 2019. doi: 10.1102/1470-7330.2004.0011.