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European Journal of Radiology 61 (2007) 424–432
Acute colonic disease: How to image in emergency
Stefania Romano ∗ , Patrizia Lombardo, Teresa Cinque,
Giovanni Tortora, Luigia Romano
Department of Diagnostic Imaging, A. Cardarelli Hospital, Viale Cardarelli 9, 80131 Naples, Italy
Received 13 November 2006; accepted 13 November 2006
Abstract
The diseases affecting the large intestine represent a diagnostic problem in adult patients with acute abdomen, especially when clinical symptoms
are not specific. The role of the diagnostic imaging is to help clinicians and surgeons in differential diagnosis for an efficient early and prompt
therapy to perform. This review article summarizes the imaging spectrum of findings of colonic acute disease, from mechanical obstruction to
inflammatory diseases and perforation, offering keys to problem solving in doubtful cases as well as discussing regarding the more indicated
imaging method to use in emergency, particularly MDCT.
© 2006 Elsevier Ireland Ltd. All rights reserved.
Keywords: Colon; Acute abdomen; Perforation; Obstruction; Appendicitis; Diverticulitis; MDCT
In the evaluation of patients with acute abdomen from suspected colonic disease, diagnostic imaging may play a first-line
important role for the patient management. From the basic imaging techniques, such as abdominal plain film and sonography,
to the more sophisticated multidetector row computed tomography, it is essential to know the radiologic findings correlated
to the different affections that can involve the large bowel in
emergency. However, although signs and symptoms can be of
added value for an effective diagnosis, it is also important to
be aware of the patients clinical conditions and to know about
his clinical history, laboratory data and results of eventual radiologic examinations previously performed, in order to operate
a correct differential diagnosis in case of doubtful findings or
mimics conditions. The aim of this review should be not just
to describe the imaging findings of colonic major emergency
(appendicitis, diverticulitis, perforations, obstructions, hemorrhage, ischemia) but to give a key of interpretation and role of
each imaging method that could be of help for a final diagnosis.
Although multislice helical CT seems to increasingly replacing ultrasonography for the evaluation of patients with acute
abdominal pain [1], it still has a role for the basic imaging
techniques. Abdominal radiograph is often performed in the
∗
Corresponding author at: Via G. Fava 28 Parco la Piramide, 80016 Marano
di Napoli (NA), Italy. Tel.: +39 333 276 0431.
E-mail address: stefromano@libero.it (S. Romano).
0720-048X/$ – see front matter © 2006 Elsevier Ireland Ltd. All rights reserved.
doi:10.1016/j.ejrad.2006.11.021
evaluation of adult patients presenting to the emergency department with acute abdomen, however, despite the great role that it
has in the past, recent data described this technique as not sensitive. In fact, in a large series of 871 patients, abdominal plain
film showed non-specificity in 68% of patients, normal findings
in 23% and abnormalities in 10% of cases [2]. However, the
initial radiological evaluation of patients with acute abdomen
with abdominal plain film, despite diagnostic limitations [3],
is widely used. In fact, traditional indications for plain film,
such as intestinal obstruction and perforation, are questioned by
helical CT [3]. Sonography can be used as basic imaging technique in acute abdomen [4], however, this methodology may
present some limitations, mostly related to the habitus of the
patients. Unlike sonography, in acute conditions CT can easily
image patients obese, with gaseous distension of the intestine;
moreover, MDCT technology has further enhanced the usefulness of this method in imaging patients with acute abdominal
pain [3].
Concerning the pathologies affecting the adult colon in emergency, appendicitis is a common disease. Acute appendicitis is
frequently clinically suspected, however, in a recent review study
it has been stated that about 50% of emergency room patients
with such a diagnosis do not have acute appendicitis and between
20 and 25% of patients undergoing appendectomy based on
clinical diagnosis have a normal appendix [5]. Because of this
reason, the role of the diagnostic imaging in evaluating suspected appendicitis seems to be of some relevance. Sonography
S. Romano et al. / European Journal of Radiology 61 (2007) 424–432
Fig. 1. Sonographic axial (a) and longitudinal (b) show marked thickening of
the appendix in a 25-year-old woman with acute appendicitis.
can be useful in diagnosing parietal thickening of the appendix
(Fig. 1), the presence of wall stratification and inhomogeneity of the peripheral fat in the adult patient with acute disease,
however, in some cases it could be difficult to effectively investigate the lower right quadrant (i.e. intestinal gaseous distension,
retrocecal appendix, scarce experience of the sonographist for
gastrointestinal disease). In most institutions there is a frequent
use of CT in evaluating patients with suspected appendicitis
(Fig. 2). It seems that with the increase of the CT use, there are
less evidences of severe imaging findings, including the absence
of periappendiceal stranding [6]. Moreover, in a recent reported
study, the use of CT seems to allow also a significant decrease in
surgical-pathologic severity of appendiceal disease and hospital
stay [6]. However, in the daily practise the combination between
abdominal plain film and sonography as well as clinical symptomatology and signs can be sufficient for diagnosing an acute
appendicitis, although some cases may require additional CT
examinations. This method is mandatory to use in evaluating
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Fig. 2. Abdominal plain film in a 35-year-old woman with acute lower right
quadrant pain showing the irregular distribution of intestinal meteorism with
some little air-fluid levels on the right (a). CT was performed, demonstrating
acute appendicitis; note the hyperdense structure in the right iliac fossa, with
inhomogeneity of the surrounding fat plane, from acute appendicitis (b).
suspected clinical complications not detected by basic imaging
tools as well in cases in which clinic evaluation is not specific
and a more accurate diagnostic technique is requested to make
a differential diagnosis (Figs. 3–5). For example, right-sided
diverticulitis is easily confused with acute appendicitis; in this
case CT findings suggesting acute right-sided diverticulitis can
be helpful, depicting a thickening of the intestinal wall and the
pericolonic inflammation [7,8], with normal appearance of the
appendix (if not involved in a more generalized flogosis).
Acute pain may involve the left lower abdominal quadrant;
this eventuality is frequently caused by diverticulitis, especially
in elderly patients [9]. Sonography and CT are the imaging methods of choice to differentiate between benign and self-limited
disorders and those which require immediate intervention [9],
being accurate in verifying diverticulitis as in establishing alternative diagnoses [9], whereas the role of plain abdominal film
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Fig. 4. CT axial image (a) of a large abscess originating in the right iliac fossa
from complicated appendicitis, well appreciable in its extension at the coronal
reconstruction (b).
Fig. 3. Predominantly gaseous distension of intestine in a 31-year-old man with
acute lower right quadrant pain; note the rounded hyperdensity in the right iliac
fossa (a) at the CT scout-view. Axial CT scan shows that the calcific formation is
an appendicolith (b); note the dishomogeneous hyperdensity of the surrounding
fat plane, in which a little bubble of extraluminal gas can be noted (arrowhead)
and the small amount of peritoneal fluid.
may be complimentary, showing an abnormal intestinal gaseous
pattern or distribution as well as reactive ileus, especially when
the disease is not in the early phase (Fig. 6). In effect, computed tomography seems a valuable imaging tool to determine
the degree of acute perforated sigmoid diverticulitis, and it can
be also of assistance in surgical planning [10]. A study exploring
the CT and demographic unfavourable outcome of nonoperative
treatment in patients with a first event of colonic diverticulitis [11] showed interesting results. In this study, the 32% of
nonoperative treatment failed; the presence of abscess or extraintestinal gas collection represented the CT findings significantly
associated with failure of non-surgical therapy, whereas sex and
age appeared not significantly associated with unfavourable outcome [11]. The attention to the parietal findings and the eventual
presence of free peritoneal or retroperitoneal air or abscess have
to be strongly kept whatever imaging technique is used, but
especially evaluating CT images (Fig. 7). The CT imaging pro-
tocol to be used in intestinal emergency can be a source of some
debate, however, despite the undoubtful help that intravenous
contrast administration can give in evaluating intestinal wall
enhancement, some reports about low dose unenhanced multidetector row CT are known. In particular, this technique seems to
have similar diagnostic performance to that of contrast enhanced
standard dose MDCT examination in patients with suspicion of
acute diverticulitis [12]; however, because the clinical suspicion is often not specific, administration of intravenous contrast
medium performing CT is useful for a differential diagnosis:
considering the acute left-sided colonic diverticulitis, different
diagnosis includes tumors, inflammatory and ischemic diseases
as well as infarctions of epiploic appendages and omentum
majus [13].
Acute epiploic appendagitis represents a not extensively
known pathology that most commonly manifests with acute
lower quadrant pain; its clinical features are similar to those
of acute diverticulitis or, less commonly, of acute appendicitis
[14]. The location is most commonly adjacent to the sigmoid
colon, whereas the acute omental infarction is typically located
in the right lower quadrant [14]. CT features of acute epiploic
appendagitis include lesion of smooth margins with attenua-
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Fig. 5. CT images of 81-year-old patient with acute abdomen; note the presence of an abscess in the right iliac fossa, continuous to the extremity of an hyperdense
appendix (black arrow in a); the small amount of peritoneal fluid and the thickened reactive appearance of the sigmoid colon (white arrow in a), appreciable also
in a more cranial scan (b); in the pelvis, the abscess caused a flogistic reaction also of some small bowel loops (arrow in c). Surgery confirmed the evidence of
complicated abscessualized appendicitis.
tion similar to the fat with surrounding inflammatory changes,
located anteriorly to the sigmoid colon wall [14]. CT features of
acute omental infarction include the presence of a triangular or
oval fatty mass with peripheral stranding between the anterior
abdominal wall and the transverse or ascending colon [14].
Another diagnostic problem in emergency evaluation of the
colon for acute disease is represented from the intestinal hemorrhage (Fig. 8), a common clinical problem which accounts for
1–2% of acute hospital admissions [15]. The colon is responsible
for approximately 87–95% of all cases of lower gastrointestinal
bleeding [15]. Although urgent colonoscopy identified a definite source of lower gastrointestinal bleeding more often than
a standard care algorithm based on angiography and expectant colonoscopy, the approaches are not different regarding
important outcome [16]. CT seems to be a safe, convenient
and accurate diagnostic tool for acute lower GI haemorrhage;
positive CT may allow directed therapeutic angiography, while
negative CT will triage patients into alternative management
pathways [17].
Diseases affecting the normal colonic transit may be of various origins: functional, mechanical, reactive and inflammatory.
Ischemic disease of the colon is certainly a well-defined clinical and radiographic entity [18], encompassing a wide spectrum
of pathologic and clinical findings, ranging from a self-limiting
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Fig. 6. Forty-three-year-old woman with history of diverticulosis and acute abdominal pain; abdominal plain film shows the irregular distribution of intestinal air
with evidence of some air-fluid level (a); CT shows thickening of the left colon with evidence of diverticular formations (b) and the presence in the pelvis of a large
abscessual mass from complicated diverticulitis (c); note also the presence of fibromiomatous formation of the utherus on the right (c).
form to bowel infarction and perforation [18]. A recent imaging
staging of disease from ischemia to infarction of the large bowel
using MDCT has been proposed [19]. However, because the
imaging findings can be similar, potentially inducing an error in
diagnostic evaluation, it is essential to know the clinical history
of the patient in order to operate a pertinent differential diagnosis
with other conditions, especially acute parietal damage induced
by chemotherapy. Intestinal obstruction of the colon (Figs. 9–11)
represents an emergency condition when at the late stage of disease. Fecaloma, foreign body and tumors are more frequently
observed in colonic occlusion, however, colonic volvolus may
also represent a condition to consider. Main problem of the diagnostic imaging method in evaluation of intestinal occlusion is
to determine the grade of compression of the wall, its viability and perfusion, in order to help surgeons to choose a more
indicated timing to perform the intervention if the ischemia of
the affected bowel segment is not present. In patients with large
intestine obstruction due to colon cancer, it is important to keep
attention to the imaging findings; in particular, cecal pneumatosis does not always indicate transmural infarction, because it may
be related to a viable bowel when similar to bubblelike pattern
or when it is not associated to other findings of ischemia [20].
S. Romano et al. / European Journal of Radiology 61 (2007) 424–432
Fig. 7. This patient came to the attention of the surgical department because
of occlusive symptomatology and abdominal left quadrant pain. CT shows the
presence of a large inhomogeneous fluid collection in the pelvis, simulating a
hyperdistended sigmoid colon (a), that surgery revealed to be a fecaloid collection from descending colon rupture, appreciable in the coronal reformation (b);
note the presence of free peritoneal air (arrowheads in c).
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Fig. 8. Elderly woman in treatment with anticoagulant drugs presenting acute
rettorrhage; MDCT shows the presence of hyperdensity in the lumen of left
colon (a), well depicted in the MIP coronal and sagittal reformations (b and c)
from active bleeding.
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S. Romano et al. / European Journal of Radiology 61 (2007) 424–432
Fig. 10. CT images of intestinal obstruction due to a descending colon neoplasm
(long arrow in a and arrow in b); note the parietal pneumatosis of the right colon
(short arrow in a) not due to colonic infarction.
Fig. 9. Intestinal obstruction in a patient with colostomy (a), CT shows the fluid
distension of the entire intestine (b) due to a recurrence of tumors at level of the
transverse colon (c).
Gaseous distension of the intestine without evidence of reactive ileus or a transition point may be a functional disorder, the
so called Ogilvie’s syndrome, that is a clinical entity characterized by massive non-toxic dilatation of the colon in the absence
of mechanical obstruction [21]. This pseudo-obstruction is a
potentially malignant early form of colonic dysmotility: colonscopic decompression can achieve reversal of colonic dilatation
S. Romano et al. / European Journal of Radiology 61 (2007) 424–432
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Fig. 11. CT images of intestinal obstruction from sigmoid colon volvolus; note
the engorgement of the torsion point (arrow in a) and the impressive coronal
reformation (b).
in most cases, but in some cases a prophylactic laparotomy may
be indicated for prevention of the perforation and additional
complications [21,22].
Other different condition of marked distension of the large
bowel is related to the toxic megacolon, that represents the
severe stage of a flogistic process (i.e. ulcerative colitis), where
additional late findings are parietal pneumatosis and perforation.
Mechanical obstruction of the colon can be easily demonstrated by basic imaging technique, however, MDCT may be of
added value to discover location of the cause of the interruption
of the intestinal transit.
Although if post-operative evaluation of the colon in most
cases do not represent an emergency condition, complications
of major surgery or recurrence of disease in case of malignancy
may cause acute disease and perforations (Fig. 12).
Despite the undoubtful usefulness of the basic imaging methods in evaluating the acute colonic disease, MDCT examination
may be of further help for an effective therapeutic management
of the patients, providing prompt valuable informations in differ-
Fig. 12. Elderly patient previously submitted to intestinal resection for neoplasm, with acute abdomen. Abdominal plain film shows free air in the
retroperitoneum (a), due to leak of anastomosis for local recurrence of disease
demonstrated by CT (b and c).
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ential diagnosis, especially in evaluating viability of the parietal
wall and the extraparietal findings and complications.
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