Differentiation of Simple and Strangulated Small-Bowel Obstructions ...

signs and symptoms of small-bowel strangulation
or did not respond favorably to
conservative treatment; they underwent
simple adhesiotomy (n = 21) or segmental
bowel resection (n = 34) to relieve the obstruction.
Obstruction was confirmed during
surgery in all 55 patients; 41 had strangulated
obstructions and 14 had simple
obstructions. Obstructions were caused by
adhesions or bands (n = 43), hernia (n =
9), or volvulus (ri = 3). The time between
surgery and CT ranged from a few hours
to 13 days (mean, 2 days); for 31 patients,
it was less than or equal to 1 day.
In the other 29 patients, obstructions improved
with fluid and electrolyte replacement
and/or after the insertion of a nasogastric
tube for 2-11 days (mean, 5 days)
for decompression; in seven of these 29
patients, long decompression tubes were
used. Although not confirmed with surgeny,
the obstructions of 14 of these 29 patients
were diagnosed with small-bowel
follow-through examinations: complete
obstruction, two patients; high-grade partial
obstruction, eight patients; and lowgrade
partial obstruction, four patients.
With use of CT criteria proposed by
Fukuya et al (10) and Gazelle et al (11),
findings consistent with small-bowel obstruction,
and not paralytic ileus, were
seen on the CT scans of 10 of the other 15
patients. Diffuse small-bowel dilatation
(luminal diameter, 3.5 cm) and collapsed
distal small bowel, colon, on both were
seen on the CT scans of these 10 patients.
On the CT scans of the other five patients,
small-bowel loops with luminal diameters
less than 3.5 cm but greater than 3.0 cm
were seen. The plain abdominal radiographs
of these five patients, obtained
within 1 week before CT, revealed findings
typical of small-bowel obstruction (distended
fluid-filled proximal loops, multiple
step-ladder patterns of air-fluid 1evels,
and collapsed distal small-bowel,
colon, or both).
We considered these 29 patients to have
simple small-bowel obstruction. To support
the belief that these patients did not
have strangulated obstruction, the number
of the following clinical features in these
29 patients was compared with that in the
41 patients with strangulated obstruction:
abdominal tenderness, tachycardia (heart
rate, > 100 beats per minute), fever (ternperature,
>38.5#{176}C),and leukocytosis (white
blood cell count, >10,000/mr& [10.0 X
109/LJ). Of the 41 patients with strangulated
obstruction, 12 patients had all four
features, 10 had three, 16 had two, and
three had one. Of the 29 patients with
simple obstruction, four patients had two
of the features, 15 had one, and 10 had
none.
CT was performed with a GE 9800
Quick System, a HiLight Advantage (GE
Medical Systems, Milwaukee, Wis), or a
Somatom Plus-S (Siemens, Erlangen, Germany)
scanner. Sections of 8- or 10-mm
thickness were imaged from the diaphragm
to the pubis at intervals of 8 or 10 mm.
Contrast material (500-800 mL; E-Z-CAT,
2% iodinated, water soluble; E-Z-Em,
Westbury, NY) was given orally 30 mm-
Table 1
Findings on CT Scansof 84 Patients with Strangulated or Simple Obstruction
CT Findings
Strangulated
(n = 41)
Simple
(n = 43)
Bowel wall changes
Smootltserrated beak 5:13 26:0
Target sign 12 3
Wall thidmess (mean ± SD, mm) 5.1 ± 2.1 3.5 ± 1.0