Median arcuate ligament syndrome (MALS) is a rare disease caused by a compression of the celiac artery by the ligament with nonspecific manifestations such as an abdominal pain and weight loss. Therefore, exclusion of other, more frequent diseases is an important part of the diagnosis. The main diagnostic tools are various imaging methods, such as angiography and computed tomography. The treatment is surgical, usually laparoscopic.
The median arcuate ligament syndrome (MALS) is associated with symptoms caused by the pressure exerted by the ligament on the celiac artery and possibly on the celiac ganglion. The condition is also named celiac artery compression syndrome (CACS), celiac axis syndrome, or Dunbar syndrome . The median arcuate ligament lies in the proximity of the aorta, close to the branch point of the celiac artery (celiac trunk), and if its position is lower than usual it may compress the celiac artery . This compression may result in ischemia which gives rise to postprandial abdominal pain and other symptoms. However, vascular problems may not be the only explanation for the condition; the median arcuate ligament also compresses the celiac ganglion and thus neurogenic effects also contribute (or could be the main factor) in the etiology of the condition .
MALS is a rare condition that mainly affects relatively young women. The predominant symptoms are an abdominal pain in the right upper quadrant and epigastric region . The abdominal pain is exacerbated by leaning forward, exercise, and food intake, and as a consequence, sitophobia accompanied by weight loss could ensue. More than 80% of patients also display epigastric bruits . The bruits, signifying the compression of the celiac trunk, are worsened on expiration. Conversely, the symptoms are temporarily ameliorated when patients bring their knees close to the chest because this position lessens the compression of the celiac trunk. Other symptoms and signs include nausea and vomiting.
Because of the rarity of the condition and the unspecific nature of the associated symptoms, other, more frequent diseases with similar symptoms such as gallbladder diseases and peptic ulcer must first be excluded. Therefore, the patients usually undergo various imaging studies.
Angiography has been the gold standard for the diagnosis of MALS. This technique can reveal stenosis of the celiac trunk . The resulting compression of the artery is increased on expiration and lowered during inspiration. However, a considerable percentage of healthy people also show marks of celiac artery compression during expiration. Therefore, it is important to view imaging results in light of the clinical observations. Sometimes, angiography also shows dilatation distal to the stenosis.
Duplex ultrasonography will detect an increased velocity of blood flow in the area of constriction. The extent of this increased velocity varies with inspiration and expiration: the maximum systolic flow velocity may be over twice as much during expiration as during inspiration .
Multidetector computed tomography (CT) scanners, coupled with three dimensional (3D) software for viewing images at different angles, have largely replaced conventional angiography. Optimal view of the stenosed celiac artery is afforded in the sagittal plane . A finding specific for MALS is the hooked character of the stenosis which helps in differentiating MALS from other conditions causing a narrowing of blood vessels, such as atherosclerosis  .