The accuracy of the CT scan depends on whether a small bowel obstruction (SBO) is present.SBO absent

prevalence of intestinal ischemia 23%
sensitivity 64%
specificity 92%
positive predictive value (at prevalence of 23%) 79%
negative predictive value (at prevalence of 23%) 95%SBO present

prevalence of intestinal ischemia 62%
sensitivity 83%
specificity 93%
positive predictive value (at prevalence of 62%) 93%
negative predictive value (at prevalence of 62%) 61%Early findings on CT scan include:

Intestinal mesenteric edema
Bowel dilatation
Bowel wall thickening
Intestinal mesenteric stranding
Evidence of adjacent solid organ infarctions to the kidney or spleen, consistent with a cardiac embolic shower phenomenonIn embolic acute intestinal ischemia, CT-Angiography can be of great value for diagnosis and treatment. It may reveal the emboli itself lodged in the superior mesenteric artery, as well as the presence or absence of distal mesenteric branches.Late findings, which indicate dead bowel, include:

Intramural bowel gas
Portal venous gas
Free abdominal air

Angiography
As the cause of the ischemia can be due to embolic or thrombotic occlusion of the mesenteric vessels or nonocclusive ischemia, the best way to differentiate between the etiologies is through the use of mesenteric angiography. Though it has serious risks, angiography provides the possibility of direct infusion of vasodilators in the setting of nonocclusive ischemia. Treatment
The treatment of intestinal ischemia depends on the cause and can be medical or surgical. However, if bowel has become necrotic, the only treatment is surgical removal of the dead segments of bowel.In non-occlusive disease, where there is no blockage of the arteries supplying the bowel, the treatment is medical rather than surgical.
Clinical findings
Symptoms of intestinal ischemia vary and can be acute (especially if embolic), subacute, or chronic.Case series report prevalence of clinical findings and provide the best available, yet biased, estimate of the sensitivity of clinical findings. In a series of 58 patients with intestinal ischemia due to mixed causes:
abdominal pain was present in 95% (median of 24 hours duration). The other three patients presented with shock and metabolic acidosis. nausea in 44%
vomiting in 35%
diarrhea in 35%
heart rate > 100 in 33%
rectal bleeding in 16% (not stated if this number also included occult blood – presumably not)
constipation in 7%

Diagnostic heuristics
In the absence of adequate quantitative studies to guide diagnosis, various heuristics help guide diagnosis:

Intestinal ischemia" should be suspected when individuals, especially those at high risk for acute intestinal ischemia, develop severe and persisting abdominal pain that is disproportionate to their abdominal findings"., or simply, pain out of proportion to exam. Regarding intestinal arterial thrombosis or embolism: "early symptoms are present and are relative mild in 50% of cases for three to four days before medical attention is sought". Regarding intestinal arterial thrombosis or embolism: "Any patient with an arrhythmia such as atrial fibrillation who complains of abdominal pain is highly suspected of having embolization to the superior mesenteric artery until proved otherwise." Regarding nonocclusive intestinal ischemia: "Any patient who takes digitalis and diuretics and who complains of abdominal pain must be considered to have nonocclusive ischemia until proved otherwise." Diagnosis
It is difficult to diagnose intestinal ischemia early.