Dr. Bender is Director of Education, Radiologic-Pathologic
Division, AFIP, Washington, DC. Dr. Maglinte is Chief of
Emergency Radiology and the Abdominal Imaging Section,
Methodist Hospital of Indiana, Indianapolis, IN. This piece is
reprinted in a modified form with permission from Emergency
Radiology, Vol. 4, pp 337-339, 1997.
With the advent of polyurethane catheters
and the rebirth of the long tube with the introduction of the
multipurpose intestinal catheter (MDEC, Cook, Inc., Bloomington,
IN), the radiologist can now become directly involved in the
diagnosis and management of small bowel obstruction (SBO).1,2
Suspected SBO is a common emergency department (ED) diagnosis, with
over 60% of cases related to adhesive disease from previous
surgery.3 The time when "the sun never [rises] on an SBO," implying
a universal need for immediate surgery, has passed. To avoid
surgery, or at the least limiting it to laparoscopic adhesiolysis,
requires rapid diagnosis and decompression.3-5 Radiologists can
fulfill much of this role if they are willing to become involved at
the emergency care level, providing a service that is available 24
hours a day. This, of course, requires that all on-call residents
and staff be comfortable with and be willing to assist in
nasointestinal tube placements.
Achieving a high rate of quality imaging studies,
if not positive outcomes, is dependent on the timing of the initial
decompression. For example, CT is best used prior to gut
decompression, while laparoscopic adhesiolysis is best accomplished
when the bowel is decompressed.4-6 Timing of the decompression is
thus critical; it is not something that should routinely be started
as soon as a patient enters the ED. Decompression should only be
started in the ED if necessary to control nausea, vomiting, and
pain. The potential need for a small bowel study, CT, or
decompression in the acute setting mandates that a multipurpose
tube, capable of supporting any of these options, should be placed
at the time of the initial plain film examination. The commonly
used Salem sump nasogastric tube cannot fulfill these functions. If
the radiologist places and monitors use of the multipurpose tube,
through serial films, diagnostic examination and decompression
management can be maximized. To simply allow indiscriminate
placement of the standard 18-F nasogastric tube in the ED for
decompression defeats an extraordinary opportunity to optimize
imaging and subjects the patient to the trauma of having to replace
the nasogastric tube. Gut decompression requires a sump and, as
such, the multipurpose triluminal catheter is ideally suited for
first line management.1,2 This tube not only can serve for gut
decompression, but also can be used for enteroclysis or
CT-enteroclysis (CT-E) when advanced beyond the pylorus.2
Ideally, CT of the abdomen and pelvis, with both IV
and gut contrast, should be performed in the acute setting.7-12 A
note of caution: with a fluid-filled, dilated gut, avoidance of
introducing any additional fluid volume is critical to patient
safety.3,6 The need for gut contrast can often be determined from
the initial abdominal plain films. If dilated loops of fluid-filled
small bowel are seen, then there is little need for gut
contrast.3,6 If the abdominal radiographic series is normal or
equivocal in the face of strong clinical evidence for SBO, then gut
contrast can be administered easily through the multipurpose tube,
which is simply advanced from its initial gastric placement into
Initially determining the grade of obstruction is
not as critical as determining whether an obstruction is present or
not.3,6,13,14 In fluid-filled gut, the mucosal enhancement that is
achieved with IV contrast alone is often sufficient to define the
presence or absence of obstruction.3 Once obstruction is
determined, decompression is critical over the first 24 to 48 hours
to prevent ischemia or other co-morbidities from developing.3,15-17
Following decompression, if subsequent feeding trials are
unsuccessful, then a CT with gut contrast, enteroclysis, or a
CT-enteroclysis can be performed to assess the severity of
obstruction and exclude complications of adhesive
When using a nasogastric tube that can be converted
into an enteroclysis catheter, CT-E is an immediate option if the
patient has not already had a diagnostic CT or if the CT itself was
equivocal.6 Early results show that if the SBO patient has a known
or suspected malignancy by history, CT-E is more accurate than CT
in identifying the site and cause of the obstruction.6,19 With
CT-E, the gut must be adequately decompressed so vomiting does not
occur with enteral contrast administration. CT-enteroclysis is
contraindicated in an SBO with undecompressed, fluid-filled gut.
Adding a large volume of fluid to bowel already distended with a
large volume of fluid only induces vomiting and increases the risk
of aspiration.3 If fluid-filled loops of bowel are seen at
fluoroscopy, the enteroclysis portion of the study should be
aborted and decompression instituted.2 In malignancy, even tube
placement can induce vomiting, so decompression prior to CT-E is
CT-E has been proposed for use in patients with low
grade obstruction, inflammatory bowel disease, and in those with
polyposis.6,19-22 Traditional enteroclysis is an alternative;
however, cross-sectional imaging (CT-E) may allow for better
surgical planning if laparoscopic adhesiolysis is available. In
addition, CT-E may have a higher sensitivity and specificity for
low-grade partial SBO lesions.6 Regardless, with the initial
placement of a multipurpose tube by the radiologist or the
emergency physician at the time the patient obtains his or her
initial plain film examination, conventional CT with SB contrast,
CT-enteroclysis, traditional enteroclysis, simple gut
decompression, or surgery all remain easy to perform options
without having to subject the patient to the trauma of multiple
intubations. For radiologists who prefer blunt end catheters for
nasoenteric tube placement, the end of the multipurpose tube can be
cut and filed smooth with an emery board. A modified enteroclysis
catheter with an end-hole is commercially available
(MAG-ENT-120-MAMC, Cook, Inc., Bloomington, IN). Most polyvinyl,
blunt enteroclysis catheters lose the function of the balloon but
not the sump effect when the end is cut. We have found that use of
the balloon is not required in grossly dilated gut, save for
possibly helping to maintain a catheter position near the ligament
The proposed "SBO watch", alluded to above, is a
useful team approach which bundles the efforts of the emergency
room physician, the general surgeon, and the radiologist together.
The radiologist must be just as available for patient care as the
other two for this approach to work. With more departments starting
to use staff radiologists to cover the emergency department
in-house at night, this approach should become more palatable and
rewarding. The greatest resistance in starting such a clinical
pathway, in our experience, is the on-call radiologist's reluctance
towards placing nasointestinal catheters and the emergency
physician's and surgeon's lack of familiarity with the multipurpose
tube. One option is to let the emergency physician, nurse, or
physician's assistant place the multipurpose tube into the stomach.
The tube functions similarly to the commonly used nasogastric tube
if the tip is in the stomach. If necessary to control nausea and
vomiting, it should be placed prior to the initial plain film
series but should ideally be introduced after the initial plain
film study. The health care provider should wait until after the
initial CT is performed to place or advance the tube into the small
bowel to prevent any tube artifact or premature decompression from
interfering with CT interpretation. If the stomach is fluid filled,
initial gastric decompression is done. Once the site and etiology
of the obstruction is determined, long tube decompression can then
occur with advancement of the tube past the ligament of
In many patients with obstructive disease secondary
to adhesions, decompression is sufficient to alleviate the
obstructive symptoms and allow a return to normal bowel function
with dietary management. As stenoses or constrictive defects become
tighter, eventual surgery can be planned based on enteroclysis
criteria for severity of obstruction and the CT criteria for
diagnosis of adhesive disease.8-15,19
The "barium-bullet" still practiced in some
institutions is to be strictly avoided, regardless of its
popularity among general surgeons, as it obviates all other imaging
options save for plain films, and all other therapeutic options
save for laparotomy.20 Endoscopy is difficult through barium, and
stent placement or balloon dilatation cannot be performed.
Certainly laparoscopic adhesiolysis is less secure with barium in
the gut, lacking full access to the bowel and peritoneal cavity
should a spill with barium occur. None of these are as important as
the information that can be missed concerning ischemic bowel when
using only portable radiographs taken on the ward as opposed to
cross-sectional imaging.3,23-27 CT is much more reliable at the
time of initial presentation, as opposed to exposing ward personnel
to the unnecessary radiation and expense of serial, low quality,
portable radiographs that simply increase the length of patient
stay (Bender GN: Unpublished data from Madigan Army Medical Center
on inpatient SBO review, 1994-1995).
In summary, to become an integral member of the SBO
management team, the radiologist must:
1. Offer immediate radiologist services 24
hours/day in making the initial reading for any abdominal
radiographs or CT prior to ED management.
2. Be available and willing to place the initial
multipurpose tube at the time the patient is in the emergency
radiology section after the initial radiographic film series, or
immediately after the CT, if obtained.
3. Educate the ED physicians and general surgeons
that CT should be obtained during the acute phase of presentation
and prior to any initial decompression so that the diagnosis of SBO
and the site of obstruction can be confirmed and other causes of
the acute abdomen reliably excluded.
4. Be available to ensure tube placement is
allowing adequate decompression of the gut, through timely
reporting of any serial abdominal radiographs and education of
nursing staff on long intestinal tube care.2
5. Be aware of the initiation, and be involved in
the follow-up of any post-decompression feeding trials through
timely reporting of any serial abdominal films.
6. Be available and capable of performing CT,
enteroclysis, or CT-enteroclysis if decompression fails, feeding
trials fail, or the persistence or recurrence of symptoms
This active participation results in optimized
imaging work-up and nonsurgical management of small bowel
obstructions, fulfilling the radiologist's role as true
1. Maglinte DDT, Stevens LH, Hall RC, et al: Dual-purpose tube
for enteroclysis and nasogastric-nasoenteric decompression.
Radiology 185:281-282, 1992.
2. Maglinte DDT, Kelvin FM, Micon LT, et al: Nasointestinal
tube for decompression or enteroclysis: experience with 150
patients. Abdominal Imaging 19:108-112, 1994.
3. Maglinte DDT, Balthazar EJ, Kelvin FM, Megibow AJ: The role
of radiology in the diagnosis of small bowel obstruction. AJR
4. Freys SM, Fuchs KH, Meimbucher J, Thiede A: Laparoscopic
adhesiolysis. Surg Endosc 8:1202-1207, 1994.
5. Francois Y, Mouret P, Tomaoglu K, Vignal J: Postoperative
adhesive peritoneal disease. Laparoscopic treatment. Surg Endosc
6. Bender GN, Timmons JH, Williard WC, Carter J: Computed
tomographic enteroclysis: one methodology. Invest Radiol 31:43-49,
7. Megibow AJ, Balthazar EJ, Cho KC, et al: Bowel obstruction:
evaluation with CT. Radiology 180:313-318, 1991.
8. Fukuya T, Hawes DR, Lu CC, et al: CT diagnosis of
small-bowel obstruction: efficacy in 60 patients. AJR 158:765-772,
9. Maglinte DDT, Gage S, Harmon B, et al: Obstruction of the
small intestine: Accuracy and role of CT in diagnosis. Radiology
10. Balthazar EJ: CT of small-bowel obstruction. AJR
11. Taourel PG, Fabre VM, Pradel JA, et al: Value of CT in
diagnosis and management of patients with suspected acute
small-bowel obstruction. AJR 165:1187-1192, 1995.
12. Maglinte DDT, Reyes BL, Harmon BH, et al: Reliability and
role of plain film radiography and CT in the diagnosis of
small-bowel obstruction. AJR 167:1451-1455, 1996.
13. Frager D, Medwid SW, Baer JW, et al: CT of small-bowel
obstruction: value in establishing the diagnosis and determining
the degree and cause. AJR 162:37-41, 1994.
14. Gazelle GS, Goldberg MA, Wittenberg J, et al: Efficacy of
CT in distinguishing small-bowel obstruction from other causes of
small-bowel dilatation. AJR 162:43-47, 1994.
15. Mucha P Jr.: Small intestinal obstruction. Surg Clin North
Am 67:597-620, 1987.
16. Fromm DG: lleus and Obstruction. In: Greenfield LJ (ed):
Surgery, pp 733-740. Philadelphia, JP Lippincott Co., 1993.
17. McLeskey CH, Janis KM: Perioperative risk and preoperative
preparation of the geriatric surgical patient. In: Katlic MR (ed):
Geriatric Surgery, pp 294-295. Baltimore, Urban and Schwarzenberg,
18. Shrake PD, Rex DK, Lappas JC, Maglinte DDT: Radiographic
evaluation of suspected small-bowel obstruction. Am J Gastroenterol
86: 175-178, 1991.
19. Walsh DW, Bender GN, Timmons JH: Comparison of computed
tomography-enterocylsis and traditional CT in the setting of
suspected partial small bowel obstruction. Emerg Radiol 5:29-37,
20. Rollandi GA, Gurone PF, Biscaldi D, et al: Malignant
tumors of small bowel: Evaluation with spiral CT and transparent
enema study. RSNA 1996; Scientific Sessions: 1053.
21. Schober E, Turetschek K, Oberhuber G, et al: Enteroclysis
spiral CT: Diagnostic yield in the preoperative assessment of
Crohn's disease. RSNA 1996; Scientific Sessions: 1358.
22. Pecher G, Kloeppel R, Thiele J: CT enteroclysis of small
bowel. RSNA 1996; Scientific Sessions: 502GI.
23. Maglinte DDT, Herlinger H, Nolan DJ: Radiologic features
of closed-loop obstruction: analysis of 25 confirmed cases.
Radiology 179:383-387, 1991.
24. Balthazar EJ, Birnbaum BA, Megibow AJ, et al: Closed-loop
and strangulating intestinal obstruction: CT signs. Radiology
25. Maglinte DDT, Herlinger H, Turner WW, Kelvin FM:
Radiologic management of small-bowel obstruction: a practical
approach. Emerg Radiol 1:138-149, 1994.
26. Frager D, Baer JW, Medwid SW: Detection of intestinal
ischemia in patients with acute small-bowel obstruction due to
adhesions or hernia: efficacy of CT. AJR 166:67-71, 1996.
27. Wolf EL, Sprayregen S, Bakel CW: Radiology in intestinal
ischemia: Plain films, contrast and other imaging studies. Surg
Clin North Am 72:114-122, 1992.