[Role of 18F-FDG-PET/CT in the assessment of carotid atherosclerosis]

Mesenteric ischemia: the importance of differential diagnosis for the surgeon

Background

Intestinal ischemia is an abdominal emergency that accounts for approximately 2% of gastrointestinal illnesses. It represents a complex of diseases caused by impaired blood perfusion to the small and/or large bowel including acute arterial mesenteric ischemia (AAMI), acute venous mesenteric ischemia (AVMI), non occlusive mesenteric ischemia (NOMI), ischemia/reperfusion injury (I/R), ischemic colitis (IC). In this study different study methods (US, CT) will be correlated in the detection of mesenteric ischemia imaging findings due to various etiologies.

Methods

Basing on our institutions experience, 163 cases of mesenteric ischemia/infarction from various cases, investigated with CT and undergone surgical treatment were retrospectively evaluated, in particular trought the following findings: presence/absence of arterial/venous obstruction, bowel wall thickness and enhancement, presence/absence of spastic reflex ileus, hypotonic reflex ileus or paralitic ileus, mural and/or portal/mesenteric pneumatosis, abdominal free fluid, parenchymal ischemia/infarction (liver, kidney, spleen).

Results

To make an early diagnosis useful to ensure a correct therapeutic approach, it is very important to differentiate between occlusive (arterial, venous) and non occlusive causes (NOMI). The typical findings of each forms of mesenteric ischemia are explained in the text.

Conclusion

The radiological findings of mesenteric ischemia have different course in case of different etiology. In venous etiology the progression of damage results faster than arterial even if the symptomatology is less acute; bowel wall thickening is an early finding and easy to detect, simplifying the diagnosis. In arterial etiology the damage progression is slower than in venous ischemia, bowel wall thinning is typical but difficult to recognize so diagnosis may be hard. In the NOMI before/without reperfusion the ischemic damage is similar to AAMI with additional involvement of large bowel parenchymatous organs. In reperfusion after NOMI and after AAMI the CT and surgical findings are similar to those of AVMI, and the injured bowel results quite easy to identify. The prompt recognition of each condition is essential to ensure a successful treatment.

Abdominal vascular emergencies: US and CT assessment

Acute vascular emergencies can arise from direct traumatic injury to the vessel or be spontaneous (non-traumatic).The vascular injuries can also be divided into two categories: arteial injury and venous injury.Most of them are life-treatening emergencies, sice they may cause an important ipovolemic shock or severe ischemia in their end organ and require prompt diagnosis and treatment.In the different clinical scenarios, the correct diagnostic approach to vascular injuries isn't firmly established and advantages of one imaging technique over the other are not obvious.Ultrasound (US) is an easy accessible, safe and non-invasive diagnostic modality but Computed Tomography (CT) with multiphasic imaging study is an accurate modality to evaluate the abdominal vascular injuries therefore can be considered the primary imaging modality in vascular emergencies.The aim of this review article is to illustrate the different imaging options for the diagnosis of abdominal vascular emergencies, including traumatic and non traumatic vessel injuries, focusing of US and CT modalities.