Imaging in Intestinal Ischemic Disorders

https://doi.org/10.1016/j.rcl.2008.05.004Get rights and content

Intestinal ischemia and infarction are a heterogeneous group of diseases that have as their unifying theme hypoxia of the small bowel or colon. The incidence of bowel ischemia and infarction is on the rise for several reasons: the aging of the population, the ability of intensive care units to salvage critically ill patients, and heightened clinical awareness of these disorders. Improvements in diagnostic imaging techniques have greatly contributed to the earlier diagnosis of intestinal ischemia, which can have a positive influence on patient outcomes. In this article, role of radiology in the detection, differential diagnosis, and management of patients who have intestinal ischemia and infarction is discussed.

Section snippets

Epidemiology

Vascular compromise of the gut is responsible for approximately 0.1% of all hospital admissions and 1.0% of admissions for an acute abdomen. The diagnosis of this disorder is on the increase for several reasons. MI and infarction occur predominantly in the geriatric population with comorbid cardiovascular disease and other systemic dysfunction. The population is aging, and the number of cases of MI is expected to increase dramatically as the “Baby Boom” generation comes of age. Other factors

Intestinal vascular anatomy

Knowledge of mesenteric vascular anatomy and physiology is key to an appreciation of the causes and consequences of intestinal ischemia and infarction. The anatomy of the mesenteric circulation is complicated by the almost endless variations of blood supply to the gut.

Physiology of the mesenteric circulation

In the fasting state, the mesenteric vessels receive approximately 20% to 25% of the cardiac output and the splanchnic circulation contains approximately one third of the total blood volume, which makes it the circulatory system's largest reservoir. Approximately 25% of the splanchnic circulation flows directly to the liver by way of the hepatic artery, and the remaining 75% of blood flow reaches the liver by way of the portal venous system.12, 16

At rest, approximately 70% to 80% of the blood

Classification of ischemic bowel disease

Intestinal ischemic disorders have been classified into several major types:17, 18, 19

  • AMI

    • SMAE

    • NOMI

    • Superior mesenteric artery thrombosis

    • Superior mesenteric vein thrombosis

  • CMI (intestinal angina)

  • CI

    • Reversible ischemic colopathy

    • Transient ulcerating ischemic colitis

    • Chronic ulcerating ischemic colitis

    • Colonic stricture

    • Colonic gangrene

    • Fulminant universal ischemic colitis

CI is the most common vascular disorder of the gut, followed by AMI. AMI is associated with compromise of the blood flow in the SMA

Small Bowel

Pathologic evidence of small bowel ischemia and infarction (Fig. 6, Fig. 7, Fig. 8) may be diffuse and confluent or patchy and multifocal. The serosal aspect of the affected small bowel often appears congested or blue and black. Perforations may be present but may not be accompanied by well-developed fibrinous exudates if the surgical resection occurs within a short time of presentation. The mesentery is usually pale in arterial occlusions and congested and hemorrhagic in venous thrombosis. The

Clinical features of mesenteric ischemia

To date, no reliable physiologic or biochemical means of detecting MI and predicting behavior have been established. Serum lactate is an established marker of cell hypoxia but lactic acidosis is often a late finding in the diagnostic pathway with concomitant shock, bowel necrosis, and circulatory collapse.22, 26

Recently, plasma D-dimer levels have been suggested as an early marker of acute ischemia. In animal studies, they have been shown to correlate with the onset of ischemia and function as

Plain Abdominal Radiographs

Most patients who have intestinal ischemia demonstrate nonspecific findings, such as intestinal dilatation (see Fig. 12), gasless abdomen, a small bowel pseudo-obstruction pattern, or paralytic ileus. More specific but far less common findings include thumbprinting in which multiple, round, smooth soft tissue densities project into the intestinal lumen because of mucosal and submucosal edema and hemorrhage. Specific late signs indicating infarction include pneumatosis intestinalis (PI; see

Acute arterial and venous mesenteric ischemia

The clinical setting of AMI is characterized by the combination of a difficult diagnosis, high fatality rates, and the need for rapid and aggressive diagnostic and therapeutic interventions in patients who are often elderly and have multiple comorbidities.26

There are four main categories of AMI: SMAE (50%), NOMI (20%–30%), SMAT (15%–25%), and superior mesenteric vein thrombosis (SMVT) (5%).1, 2, 3

Chronic mesenteric ischemia

Atherosclerosis of the mesenteric circulation is quite common, particularly in the elderly population. Symptomatic CMI, however, is rare because of the development of extensive collaterals. Risk factors for the development of CMI include a positive family history, smoking, hypertension, and hypercholesterolemia, the same risk factors as for atherosclerosis. There is a female predominance of symptomatic disease.

Nonatherosclerotic causes of CMI are less frequent and include celiac artery

Colonic ischemia

CI is the most common vascular disorder of the gut in elderly patients. The colon is predisposed to ischemia because of the fact that it receives less blood flow per gram of tissue than does the remainder of the gastrointestinal tract.28, 29 Indeed, there is an extensive network of intramural vessels arising from the vasa recta and vasa brevia in the mesenteric border of the gut that gives rise to a microvascular plexus in the muscularis propria and submucosal layer and is less well developed

Pneumatosis intestinalis

Intramural gas is associated with several disorders ranging from life-threatening to benign.82 PI pathogenically derives from four major categories: bowel necrosis, mucosal disruption, increased mucosal permeability, and pulmonary disease.83 The first three causes may be found in patients who have intestinal ischemia (see Fig. 13, Fig. 14, Fig. 1520, and 21). In patients who have intestinal ischemia, gas may dissect from the intestinal lumen because of an increase in intraluminal pressure (eg,

Focal segmental mesenteric ischemia

Short-segment ischemic disease may be caused by a large number of disorders, including vasculitis, medications, surgery, radiation, neoplasm, and, most importantly, bowel obstruction. Most cases of localized MI show similar radiologic features. It is important, however, to determine the underlying cause to guide diagnostic and therapeutic planning. The clinical presentation of localized MI depends on the length and distribution of the ischemia and the course of disease.30, 33

With the exception

Therapeutic options

Patients who are suspected of having AMI require volume resuscitation; correction of hypotension, congestive heart failure, and cardiac arrhythmias; correction of acid-base and electrolyte abnormalities; and infusion of broad-spectrum antibiotics offering theoretic protection against the bacterial translocation that accompanies loss of mural integrity.26 Specific therapies are discussed next.

Summary

Gastrointestinal tract ischemia can threaten bowel viability with potentially catastrophic consequences, including intestinal necrosis and gangrene. Because presenting symptoms and signs are relatively nonspecific and imaging findings may be confusing, the diagnosis of intestinal tract ischemia requires a high index of suspicion. It is important to attempt to determine the cause of the intestinal ischemia and differentiate between intestinal ischemia and infarction. The early inclusion of bowel

References (87)

  • A.Y. Kim et al.

    Evaluation of suspected mesenteric ischemia: efficacy of radiologic studies

    Radiol Clin North Am

    (2003)
  • H.K. Ha et al.

    CT and MR diagnoses of intestinal ischemia

    Semin Ultrasound CT MR

    (2000)
  • R.M. Gore et al.

    Miscellaneous abnormalities of the colon

  • E.J. Wolf et al.

    Radiology in intestinal ischemia. Plain film, contrast, and other imaging studies

    Surg Clin North Am

    (1992)
  • S.E. Rubesin

    Miscellaneous abnormalities of the small bowel

  • S.T. Kim et al.

    Angiography and interventional radiology of the hollow viscera

  • C.F. Dietrich et al.

    Sonographic assessment of the splanchnic arteries and the bowel wall

    Eur J Radiol

    (2007)
  • H.J. Michaely et al.

    Abdominal and pelvic MR angiography

    Magn Reson Imaging Clin N Am

    (2007)
  • B.E. Van Beers et al.

    Imaging of intestinal ischemia

    J Radiol

    (2004)
  • E. Segatto et al.

    Acute bowel ischemia: CT imaging findings

    Semin Ultrasound CT MR

    (2003)
  • K.M. Horton et al.

    Computed tomography evaluation of intestinal ischemia

    Semin Roentgenol

    (2001)
  • K.M. Horton et al.

    Multidetector CT angiography in the diagnosis of mesenteric ischemia

    Radiol Clin North Am

    (2007)
  • G. Angelelli et al.

    Acute bowel ischemia: CT findings

    Eur J Radiol

    (2004)
  • R. Lee et al.

    CT in acute mesenteric ischaemia

    Clin Radiol

    (2003)
  • L.J. Brandt

    Intestinal ischemia

  • H. Yasuhara

    Acute mesenteric ischemia: the challenge of gastroenterology

    Surg Today

    (2005)
  • U. Haglund et al.

    Intestinal ischemia—the basics

    Langenbecks Arch Surg

    (1999)
  • J.J. Kolkman et al.

    Clinical approach to chronic gastrointestinal ischaemia: from “intestinal angina” to the spectrum of chronic splanchnic disease

    Scand J Gastroenterol Suppl

    (2004)
  • P.A. Clavien et al.

    Venous mesenteric infarction: a particular entity

    Br J Surg

    (1988)
  • S. Korotinski et al.

    Chronic ischaemic bowel diseases in the aged—go with the flow

    Age Ageing

    (2005)
  • I.G. Schoots et al.

    Systemic review of survival after acute mesenteric ischemia according to disease aetiology

    Br J Surg

    (2004)
  • A.J. Comerota et al.

    Mesenteric ischemia

  • D.A. Tendler

    Acute intestinal ischemia and infarction

    Semin Gastrointest Dis

    (2003)
  • J. Hart

    Non-neoplastic diseases of the small and large intestine

  • J. Rosai

    Gastrointestinal tract

  • S.B. Goldin et al.

    Anatomy and physiology of the mesenteric circulation

  • M. Ujiki et al.

    Mesenteric ischemia

    Perspect Vasc Surg Endovasc Ther

    (2005)
  • J. Sreenarasimhaiah

    Diagnosis and management of intestinal ischaemic disorders

    BMJ

    (2003)
  • M. Trompeter et al.

    Non-occlusive mesenteric ischemia: etiology, diagnosis, and interventional therapy

    Eur Radiol

    (2002)
  • R.W. Chang et al.

    Update in management of mesenteric ischemia

    World J Gastroenterol

    (2006)
  • C. Bakal et al.

    Radiology in intestinal ischemia: angiographic diagnosis and management

    Surg Clin North Am

    (1992)
  • S. Romano et al.

    Ischemia and infarction of the small bowel and colon: spectrum of imaging findings

    Abdom Imaging

    (2006)
  • Mirvis SE, Shanmuganathan K, Erb R. Diffuse small-bowel ischemia in hypotensive adults after blunt trauma (shock...
  • Cited by (44)

    • Imaging of Gastrointestinal Tract Perforation

      2020, Radiologic Clinics of North America
    • Imaging in Gastroenterology

      2018, Imaging in Gastroenterology
    • Diagnostic Imaging: Gastrointestinal

      2015, Diagnostic Imaging: Gastrointestinal
    • Evaluating Patients with Left Upper Quadrant Pain

      2015, Radiologic Clinics of North America
      Citation Excerpt :

      The splenic flexure is particularly sensitive to ischemia because it lies at Griffin point, the watershed between the middle colic and left colic artery blood supply.20 Colonic ischemia (CI) is divided into 6 categories that reflect pathologic changes and clinical severity: milder forms, such as reversible ischemic colopathy and transient ulcerating IC; severe forms, such as colonic gangrene and fulminant universal IC; and chronic forms, including colonic stricture and chronic ulcerating IC.98 The clinical course of the disease can take 2 forms, a mild self-limited form that resolves in approximately 2 weeks in about half of patients and a fulminant form with gangrenous ischemia with a greater than 50% mortality rate.98–100

    View all citing articles on Scopus
    View full text