Most patients with chronic, undiagnosed abdominal pain have had many gastrointestinal tests performed, including EGDs, gastric emptying studies, colonoscopies, Bravo esophageal pH tests, CT scans, and ultrasounds. While these tests may not give patients the answers they’re looking for, they might still hold the answer that doctors aren’t looking for: MALS.
The two most common ways to diagnose MALS are an abdominal CT scan with contrast and a doppler ultrasound of the celiac artery. A CT scan provides a better look at the anatomy involved, while an ultrasound shows the blood-flow velocities. In order to spot MALS in either of these tests, skill is needed both on the part of the technicians performing the test and the radiologists and doctors who read them.
To find MALS on a CT scan, it is helpful (though not entirely necessary) for the patient to hold an exhale position, as it makes the characteristic “hook” shape of the celiac artery more apparent. If the image is taken while the patient inhales, it is possible for the hook to be less pronounced, which increases the likelihood of a missed diagnosis. This is why properly educated and trained technicians are so vital in the diagnosis of MALS. Another potential MALS indicator that can be seen on a CT scan is an abnormally low diaphragm. A low diaphragm increases the likelihood that the median arcuate ligament is too close to the celiac artery, causing the compression of the artery and the celiac ganglion bundle.
Because a compression on the celiac artery can cause a change in blood flow velocities, a doppler ultrasound can also be used to diagnose MALS. The normal velocity through the celiac artery is 98-100 centimeters per second; stenosis (blockage) is suspected when velocities rise above 200 cm/sec. A stenosis can be indicative of a MALS diagnosis. However, as with a CT scan, ultrasounds require a skilled and educated technician who can properly instruct the patient on the necessary positions to hold as the ultrasound is being performed. Because of the increased difficulty in a MALS-specific ultrasound and the variations between techniques and technicians, ultrasounds may be a less conclusive diagnostic tool.
Many patients may already have had the testing necessary to diagnose MALS, though they and their doctors may be unaware–and yet most patients endure pain for years while wading through numerous tests and misdiagnoses. Raising awareness for this diagnosis is imperative if doctors hope to help patients restore their quality of life.
Image credit: https://www.ceessentials.net/articl… (The yellow arrow indicates the celiac artery; the red arrow indicates the superior mesenteric artery. The first image shows the hook-like appearance of the celiac artery, while the second image shows a normal, unconstricted artery.)