Insights into acute mesenteric ischaemia: an up-to-date, evidence-based review from a mesenteric stroke centre unit

Abstract

Radiologists play a central role in the diagnostic and prognostic evaluation of patients with acute mesenteric ischaemia (AMI). Unfortunately, more than half of AMI patients undergo imaging with no prior suspicion of AMI, making identifying this disease even more difficult. A confirmed diagnosis of AMI is ideally made with dynamic contrast-enhanced CT but the diagnosis may be made on portal-venous phase images in appropriate clinical settings. AMI is diagnosed on CT based on the identification of vascular impairment and bowel ischaemic injury with no other cause. Moreover, radiologists must evaluate the probability of bowel necrosis, which will influence the treatment options. AMI is usually separated into different entities: arterial, venous, non-occlusive and ischaemic colitis. Arterial AMI can be occlusive or stenotic, the dominant causes being atherothrombosis, embolism and isolated superior mesenteric artery (SMA) dissection. The main finding in the bowel is decreased wall enhancement, and necrosis can be suspected when dilatation >25 mm is identified. Venous AMI is related to superior mesenteric vein (SMV) thrombosis as a result of a thrombophilic state (acquired or inherited), local injury (cancer, inflammation or trauma) or underlying SMV insufficiency. The dominant features in the bowel are hypoattenuating wall thickening with submucosal oedema. Decreased enhancement of the involved bowel suggests necrosis. Non-occlusive mesenteric ischaemia (NOMI) is related to impaired SMA flow following global hypoperfusion associated with low-flow states. There are numerous findings in the bowel characterised by diffuse extension. An absence of bowel enhancement and a thin bowel wall suggest necrosis in NOMI. Finally, ischaemic colitis is a sub-entity of arterial AMI and reflects localised colon ischaemia-reperfusion injury. The main CT finding is a thickened colon wall with fat stranding, which seems to be unrelated to SMA or inferior mesenteric artery lesions. A precise identification and description of vascular lesions, bowel involvement and features associated with transmural necrosis is needed to determine patient treatment and outcome.

Diagnostic Role of Multi-Detector Computed Tomography in Acute Mesenteric Ischemia

“…An uncommon cause of arterial thrombosis is SMA dissection, which can occur as a continuation of aortic dissection or in isolation [ 49 ]; spontaneous isolated superior mesenteric artery dissection is defined as superior mesenteric artery (SMA) dissection without the presence of aortic dissection [ 50 ]. SMA spontaneous dissection is a rare cause of mesenteric ischemia (<5%) in males between the fourth and the fifth decade with no particular medical history [ 17 ], and typically affects the convex surface of the SMA trunk, at a distance of 1 to 3 cm away from the root [ 51 ]. Many classifications have been proposed for SMA dissection [ 50 , 52 , 53 , 54 ] to determine the shape, location, and extent of the false lumen, and whether the false lumen is thrombosed or the true lumen is stenotic.…”

“…Although both the large and small intestine can be involved, characteristically, the bowel alterations are discontinuous and segmental. Other abdominal signs of the CT hypoperfusion complex can be appreciated such as a small-caliber aorta, a collapsed inferior vena cava, bowel mural hyperenhancement, and a hyperenhancement of the kidneys and adrenal glands [ 2 , 6 , 11 , 17 , 19 , 60 ]. Parenchymal infarcts are often associated with NOMI.…”

“…MDCTA can detect the vascular occlusion of mesenteric arteries or veins and demonstrate downstream bowel wall injury. Moreover, MDCTA allows differential diagnosis between intestinal ischemia subtypes, which is mandatory to guide the correct management [ 17 ]. Therapeutic management requires a multidisciplinary approach of general or abdominal surgeons, vascular surgeons, interventional radiologists, and intensivists, according to the recommendations of WSES (World Society of Emergency Surgery) [ 10 ].…”

Case report: Rapid development of acute symptomatic portal vein system thrombosis after endoscopic variceal therapy in a patient with liver cirrhosis

“…Portal vein system thrombosis (PVST), mainly including portal vein thrombosis (PVT), superior mesenteric vein (SMV) thrombosis, and splenic vein thrombosis, is a common complication of liver cirrhosis ( 1 ), with a prevalence of 11.18%–16.91% and an incidence of 8.16%–12.92% ( 2 ). While PVST is often asymptomatic in liver cirrhosis and even transient ( 3 ), a subset of PVST patients may develop acute and progressive manifestations related to intestinal ischemia, such as abdominal pain, and even intestinal necrosis ( 4 ).…”

Therapeutic effect and study of human umbilical cord blood mononuclear cells in patients with ischaemic bowel disease

“…Ischaemic bowel disease (IBD) is a series of intestinal ischaemic syndromes due to an insufficient blood supply to the intestine caused by intestinal ischaemia and hypoxia 1 . The factors leading to this disease can be divided into acute mesenteric ischaemia (AMI), chronic mesenteric ischaemia (CMI) and ischaemic colitis (IC) 2 .…”