CMI is an incapacitating disease and timely diagnosis remains problematic. Despite the substantial compensatory capacity of the mesenteric circulation CMI is relatively common, its incidence being comparable to other well-known diseases like Crohn's disease.

Diagnostic tools are needed for two purposes since the exclusion of CMI currently requires a cumbersome complication-prone diagnostic workup and since a definitive diagnosis is mainly established per exclusionem. First, a sensitive test is desirable to rule out CMI and avoid excessive diagnostic investigations. Quantification of mesenteric arterial calcification on computed tomography (CT) seems suitable for this purpose, synonymous with the coronary artery calcium score. Second, a specific test is required confirming CMI by detection of mucosal ischemia during a meal, when oxygen demand peaks. A breath test, based on the requirement of oxygen to absorb and metabolize 13C-butyrate in the enterocyte, could detect mucosal ischemia

Objective: Facilitating diagnosis of chronic mesenteric ischemia (CMI) using 1) the mesenteric artery calcium score (MACS) and 2) mucosal ischemia detection by butyrate breath testing

Study design: Multicentre prospective cohort studies.

Inclusion Criteria:

• Patients with a clinical suspicion of CMI referred to Maagdarm Ischemie Centrum Rotterdam (MICR), MST or UMCG.
• Patients ≥ 18 years

Exclusion Criteria:

• Patients who are unable to give informed consent
• Patients with previous mesenteric artery revascularization
• No available CT imaging and contraindications for CT imaging (e.g. pregnancy)
• Common origin of the celiac artery and superior mesenteric artery
• Known delayed gastric emptying
• Known and untreated small intestinal bacterial overgrowth

All patients with suspected CMI