contrast medium injection in ct performed for bowel obstruction: is it really useful?
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Contrast medium injection in CT performed for bowelobstruction: is it really useful?
Poster No.: C-1059
Congress: ECR 2015
Type: Scientific Exhibit
Authors: D. Picone, F. Vernuccio, F. Rabita, C. Tudisca, L. Scopelliti, M. C.Galfano, F. Midiri, G. La Tona, G. Lo Re; Palermo/IT
Keywords: Abdomen, CT, Contrast agent-intravenous, Obstruction /Occlusion
DOI: 10.1594/ecr2015/C-1059
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Aims and objectives
Bowel obstruction (BO) accounts for 15-20% of admissions to emergency department foracute abdomen. As demonstrated in literature, although abdominal CT can be performedwithout intravenous contrast medium injection, it facilitates good accuracy and diagnosticconfidence [1].
CT is becoming a mainstay in diagnosing BO since it can determine whether there is amechanical obstruction, the level of obstruction, and whether obstruction is associatedwith bowel ischemia, and finally help to recommend BO management: medical orsurgical, and if surgical, whether laparotomy or laparoscopy [2-6]. However, there are nostudies which compare CT and surgical reports in patients with large BO. The aim of ourstudy was to evaluate the usefulness of contrast medium to diagnose BO and its causein patients with acute abdominal pain.
Methods and materials
From March 2010 to 2014, a series of 89 patients (38 males, 50 females, mean age68,67±16,10 years), who had surgery because of BO and had undergone an abdominalCT before surgery were included. However, 11 patients were excluded because CT hadnot been performed in our Hospital; 2 patients were excluded because there were not allthe necessary data in the medical records. Hence, 76 patients (33 males, 43 females,mean age 68,61±16.18 years) who had had surgery because of BO and performed CTin our Hospital, were considered in our study . All the patients underwent abdominal CTusing a 16-row multislice CT. 21 of the patients received, based on their weight, 80 ml to130 ml of iodinated contrast material (320, 350, 370 e 400 mg iodine/ml), injected througha user programmable single-head injection system, through an antecubital vein at a rateof 2.5 - 3.5 ml/s, according to the venous access available. The reports of the initial CTwere compared with the surgical reports. In case of discrepancy, we evaluated in whichcases contrast medium could be avoided or should have been injected.
Results
In 61,8% of the patients, the cause of BO was correctly diagnosed on CT (group a), whilein 35,6% of the patients it had not been reported on the CT report and was detectedat surgery (group b). In 2,6% out of 76 patients the cause of BO had not been clearlyidentified by CT and surgery definitively clarified the diagnosis. Among patients whowere correctly diagnosed 31,9% were injected contrast medium (Figure 1 and Figure2), and in 53,3%of these medium contrast injection could be avoided. 57 of the 76
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patients underwent abdominal surgery within 24 hours since CT examination, while 19patients underwent abdominal surgery after 24 hours since CT examination (Table 1).Among patients who were correctly diagnosed 31,91% (15 out of 47) had undergonecontrast medium injection; in 8 of the 15 cased the medium contrast could certainlybe avoided since the cause of obstruction (hernia, incisional hernia, volvulus or post-surgical adhesions) could be easily detected without contrast medium administrationand the diagnosis of BO could have been done on unenhanced CT. 22,22% (6 out of27) of the patients in whom the cause of the obstruction had not been identified on CThad undergone contrast medium injection. Between the two groups there was not anystatistically significant difference in diagnosing the cause of the obstruction with or withoutcontrast medium injection (p=0.37). Hence, contrast medium injection would not havechanged the accuracy in the diagnosis of the cause of BO. Table 2 reports the cause ofBO in case of "missed diagnosis".
Images for this section:
Table 1: Table 1. Characteristics of 76 Patients who were diagnosed bowel obstructionat CT and underwent surgical operation
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Fig. 1: Figure 1. CT examination before and after intravenous injection of contrastmedium in a patient with operated colorectal cancer shows concentric wall thickening atthe mid-distal sigmoid tract and in contiguity with the colorectal anastomosis. This wallthickening shows inhomogeneous enhancement after contrast medium injection. Thediagnosis of recurrent colorectal cancer was made.
Fig. 2: Figure 2: CT examination performed before and after intravenous injection ofcontrast medium in a patient that had been recently operated for carcinoma of theextrahepatic bile ducts with hepatic-jejunostomy. CT showed in the second duodenalportion the presence of solid tissue, which was responsible of stenosis of the lumen,associated visceral gastrectasia and distention of the duodenal bulb. This tissue seemsto have not surgical planes of cleavage from the head of the pancreas.
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Table 2: Table 2. Cause of misdiagnosed bowel obstruction.
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Conclusion
One of the main goals of the radiologist in patients with BO that undergo CT is todetermine the most likely cause of the obstruction. The cause of BO may be mechanicalor functional; however, on CT it is just possible to determine mechanical causes of bowelobstruction. As we demonstrated, in most of the patients, contrast medium injection couldbe avoided for diagnosing BO and the use of contrast medium did not affect the accuracyin diagnosing the etiology of BO. However, further studies on a larger population areneeded.
Personal information
Dario Picone, [email protected]
Federica Vernuccio, [email protected]
Fabrizio Rabita, [email protected]
Giuseppe Lo Re, [email protected]
References
1. Atri M, McGregor C, McInnes M, Power N, Rahnavardi K, Law C, Kiss A. Multidetectorhelical CT in the evaluation of acute small bowel obstruction: comparison of non-enhanced (no oral, rectal or IV contrast) and IV enhanced CT. Eur J Radiol 2009;71:135-402. Silva AC, Pimenta M, Guimarães LS. Small bowel obstruction: what to look for.Radiographics 2009; 29:423-39.3. Hayakawa K, Tanikake M, Yoshida S, Urata Y, Yamamoto E, Morimoto T. Radiologicaldiagnosis of large-bowel obstruction: neoplastic etiology. Emerg Radiol. 2013; 20:69-76.12.00
4. Megibow AJ, Balthazar EJ, Cho KC, Medwid SW, Birnbaum BA, Noz ME. Bowelobstruction: evaluation with CT. Radiology 1991; 180:313-8.
5. Deshmukh SD, Shin DS, Willmann JK, Rosenberg J, Shin L, Jeffrey RB. Non-emergency small bowel obstruction: assessment of CT findings that predict need forsurgery. Eur Radiol 2011; 21:982-6.
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6. Frager D, Medwid SW, Baer JW, Mollinelli B, Friedman M. CT of small bowelobstruction: value in establishing the diagnosis and determining the degree and cause.AJR Am J Roentgenol 1994; 162:37-41.