A 12-year-old African American girl presented to the emergency room with an acute exacerbation of chronic
abdominal pain and bloody stools. Subsequent small bowel follow-through was negative for Crohn's disease.
CT scanning and MR imaging was performed.
Prepared by Dr. Brian Burke and Dr. John Pellerito of the
Department of Radiology, North Shore University Hospital,
Manhasset, NY; Dr. Justin Zack of the Department of Radiology,
University of Texas Health Sciences Center, San Antonio, TX;
and Dr. Nasser Razack of the Department of Radiology,
University of Virginia Medical Center, Charlottesville,
A 12-year-old African-American girl presented to the emergency
room with an acute exacerbation of chronic abdominal pain and
bloody stools. Subsequent small bowel follow-through was negative
for Crohn's disease. CT scanning and MR imaging was performed
(figures 1 and 2).
Inferior mesenteric vein (IMV) thrombosis
Mesenteric thrombosis was first described by Antonio Beniviene
In 1935, Donaldson and Stout
better categorized mesenteric thrombosis as arterial or venous in
origin. Warren and Eberhardt
divided the causes into four broad categories: 1) infection, 2)
hematologic disorders, 3) trauma, and 4) mechanical causes.
Mesenteric venous thrombosis most commonly involves the superior
mesenteric vein (SMV) and has been associated with hypercoagulable
states (antithrombin III, protein C or S deficiencies), trauma,
diverticulitis, appendicitis, Crohn's disease, oral contraceptives,
sepsis, abdominal abscess, peritonitis, neoplasm, cirrhosis,
volvulus, mechanical bowel obstruction and postoperative state.
Inferior mesenteric vein (IMV) thrombosis is much less common than
SMV thrombosis and accounts for approximately 6% of all cases of
mesenteric venous thrombosis.
Clinical presentation includes severe abdominal pain that is out
of proportion to physical findings and typically presents without
rebound or guarding. Nausea, vomiting, and diarrhea are
inconsistent signs and hematemesis or hematochezia may occur in
advanced disease with bowel necrosis.
As opposed to mesentenic arterial thrombosis, which usually
presents as an acute event, venous thrombosis often occurs with
subacute symptoms lasting 1 to 4 weeks prior to presentation.
Plain films of patients with IMV thrombosis demonstrate
non-specific findings including ileus, ascites, bowel wall
thickening, or mucosal abnormalities ("thumb printing"). Ultrasound
may demonstrate a dilated IMV with echogenic thrombus and the
absence of flow on Doppler examination; however, patient habitus or
air within distended loops of bowel may compromise this
Shapir et al
reviewed 70 normal abdominal CT scans and were able to identify the
IMV in 14 cases. The IMV allows venous drainage from the descending
and sigmoid colon. It lies within the descending mesocolon in the
left anterior pararenal space. The IMV runs anterior to the left
psoas muscle and Gerota's fascia. Although it may be confused with
the left gonadal vein, the gonadal vein lies within the perirenal
space and posterior to the IMV. The IMV lies anterior to the left
ureter and lateral to the inferior mesenteric artery (IMA). Higher
in the abdomen, the IMV is typically located posterior to or to the
left of the duodenal-jejunal junction. The IMV drains into either
the splenic vein, the splenoportal confluence, or the superior
mesenteric vein. The normal IMV diameter is reported to be 3 to 6
mm, in the case of portal hypertension it may be enlarged.
The typical contrast-enhanced CT imaging findings in IMV thrombosis
include the presence of low-density thrombus in the normal course
of the IMV (figure 1). The vein is typically enlarged and
demonstrates rim enhancement around the central low-density
thrombus. The rim enhancement likely represents enhancement of
venous wall vasa vasorum.
The tubular nature of the vessel is confirmed on serial axial
images. Other findings may include bowel wall thickening, ascites,
or pneumatosis. Ultrasound imaging will reveal an enlarged IMV with
absence of flow on color Doppler examination (figure 3).
Magnetic resonance imaging demonstrates enlargement of the IMV
with absence of flow void that can be followed on contiguous slices
(figure 2). A central area of high signal intensity surrounded by
intermediate signal within the IMV represents thrombus (figure 2).
The IMA is seen as a small area of flow void found just anterior
and to the left of the aorta on MRI (figure 2). Magnetic resonance
venography (MRV) may demonstrate the enlarged IMV with absence of
flow void. Angiography demonstrates arterial spasm with slow flow,
dense opacification of the bowel mucosa with absent venous runoff,
or occasionally, thrombus within the IMV.
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2. Donaldson JK, Stout BF: Mesenteric thrombosis. Am J Surg
3. Warren S, Eberhard TP: Mesenteric vascular thrombosis. Surg
Gynec & Obst 61:102-111, 1935
4. Geyer DE, Krenning LE: Mesentenic venous thrombosis: A case
report. J Fam Pract 36:454-456, 1993.
5. Shapir J, Rubin J: CT appearance of the inferior mesenteric
vein. J Comp Assist Tomog 8:877-880, 1984.
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