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Diagnostic Imaging workup for intestinal obstruction

Posted by ajmorillo on 29 Jul 2009 at 02:31 GMT

I disagree completely with the use of a plain abdominal film in this case or in any case like this one. It may be that plain films still show some of the classic signs of fecal impaction, and that measurements can still be made in some cases, granted that the massive distention allows for a clear depiction of the borders of the intestinal loop one might be interested in measuring (I doubt the measurements shown of the plain film correspond to the intestinal loop of interest). Indeed, plain films in this case showed nothing useful. The truly useful information regarding the extent of the dilatation of the loops, the best way to detect free intraperitoneal air, the clear depiction of fluid levels, intra or extraluminal, especially in a patient that cannot stand up, can only be obtained with an abdominal CT. In the 21st century, I doubt an abdominal plain film has anything to offer against a multidetector CT (MDCT). This case illustrates the continuing use of useless examinations that only lead to more exams. The clinical presentation was obvious enough to predict the plain film findings. A cheaper exam might have only increased the costs in this case, or in a hundred cases like this one. Multiply the cost of an abdominal plain film in any country by one hundred, that is the amount you will save in the long run by taking this kind of patients, not uncommonly seen in general hospitals, directly to your MDCT's in your next 100 cases. As a radiologist, I appreciate having learnt to see those signs on the plain films I had to wrestle with during my residency. But we must move on, and accept and promote the use of more efficient imaging tests, that avoid lengthy discussions about the possibility of a small or not-so-small bubble of extraluminal air, the need for additional cross-table views, and the postponing of crucial decisions of older patients that are only interested in being alleviated, not in becoming part of an interesting vouyeuiristic excercise for amateurs. The abdominal plain film should be banned in most of the clinical situations it is still used for; even if diagnosis can be made with this precarious method, I can think of very few cases in which the workup stops with an abdominal X-Ray, especially in situations like the one presented, in which clinical or surgical decisions are to be made. In a hundred cases just like this one, how many patients would have had an abdominal CT anyway? If our guess is 50% or more, then we should consider if our next patient is worth the flip of a coin. Again, as a trained radiologist, I am quite sure that the diagnosis of fecal impaction would have been as straightforward with the plain film findings shown, as I am certain that the next diagnostic imaging step would have been the same exam that was performed in this case: MDCT.

No competing interests declared.

RE: Diagnostic Imaging workup for intestinal obstruction

salo75 replied to ajmorillo on 29 Jul 2009 at 08:33 GMT

Dear Colleague, thanks for raising an interesting discussion about this topic. If I well understood your concerns, you disagree with the use of a Plain Abdominal x-ray as initial diagnostic and evaluation step for a patient with intestinal obstruction, suggesting to skip straightforward to CT scan. Now as an emergeny surgeon and emergency department consultant let me ask to you, trained radiologist, the following questions.
If a patient with clinical signs of intestinal obstruction and a grossly distended abdomen, as in the clinical picture of the patient, comes to the emergency department of your hospital, does the emergency physician or surgeon request immediately a multidetector CT scan, sending the patient from casualty to CT scan room in the radiology department? How many obstructed patients does your ED admit every day and every night? How many MDCT scan your Emergency consultants ask for, every day and every night? Every obstructed patient in your hospital gets a CT scan done?? Unfortunately, in our hospital in Bologna, Italy, casualty dept has more than 300 patient to be seen every day, with any diagnosis, trauma, medical and surgical emergencies etc, and we can not overload CT scan and scan every patient. In this case we were concerned because of the massive abdominal distension, but we were also quite confident since at the clinical assessment the abdomen was soft and non peritonitic. The plain x-rays resulted very useful to us for the initial assessment of the patient, confirming the huge feacal impaction with colonic dilatation, in absence of free air or air fluid levels. That was more than enough information for us to plan the best management for the patient in the following hours and days, without need to overload the CT scan and radiology department with a non urgent CT scan. In fact this radiological findings were consistent with the past medical history of the patient and his previous episodes of fecal impaction with partial bowel obstruction. Otherwise we clearly stated in the paper and in the flow chart: "When in doubt, or when the clinical and radiological findings are not clear enough
to suggest the best further diagnostic steps, abdominal computed tomography (CT)", and in these events we fully agree with your point of view. Furthermore in the following days, since after 10 days of Non operative conservative management, the patient did not significantly improve, we planned a non urgent MPR CT scan for clarifying the case and excluding other possible concomitant obstructing lesions.
I am also not convinced at all by some of your statements: you deine plain x-ray a useless exam: in our case it has been enough useful to rapidly assess the patient and plan his further management. Even more, given that, as you said, "the clinical presentation was obvious enough to predict the plain film findings" and therefore the diagnosis of a further episode of fecal impaction, why should we have done immediately an emergency CT scan straightforward? You also speak about the costs: How much does it cost, in time and money, a plain film against a MDCT? How many patients, even with serious cases of bowel obstruction, can you assess in a reliable way with a simple plain x-ray and, together with the clinical findings, decide to send to OR or for observation? Also if the plain x-ray shows a large bowel obstruction, how do you, radiologist, proceed further to investigate for a possible stenosing lesion of the colon? A water soluble contrast enema can be more than enough, in emergency settings, in diagnosing an obstructing colonic cancer, probably even more sensitive than CT scan (does the CT scan represents the gold standard in diagnosing colonic cancer, against contrast enema or colonoscopy? I do not think so!). Even in the case of adhesive small bowel obstruction a water soluble follow through study with hyperosmolar contrast cab be diagnostic as well therapeutic (see recent literature about therapeutic value of water soluble hyperosmolar contrast medium in ASBO). Also, in promoting the use of CT scan, you mentioned "about the possibility of a small or not-so-small bubble of extraluminal air" and also stated "I can think of very few cases in which the workup stops with an abdominal X-Ray, especially in situations like the one presented, in which clinical or surgical decisions are to be made"; however please note that, in most of the clinical situations, a careful clinical exam and evaluation of the patients, with his signs and symptoms, together with a plain abdominal x-ray, is enough, at least in emergency, to decide wheter or not the patients needs an urgent laparotomy or can be admitted for clinical observation, or can be discharged and eventually followed up as outpatient. For example a careful and serial clinical evaluation, together with labs and plain x-ray is usually in most of the cases, enough for assessing the patient in an emergency setting and diagnosing free intra-abdominal air caused from intestinal perforation. As well, as an emergency surgeon, I can say that the evaluation of a need for laparotomy in the case of bowel obstruction, is, in many of the most severe cases, made based first on clinical signs and symptoms together with a plain abdominal x-ray, regardless of further examinations. Finally the measurement have been done not for clinical evaluation of the patient but lately during the radiological re-evaluation of the case. Obviously they were not critical for the management of the patient but they were useful in the evaluation of the radiological severity of the fecal impaction. Furthermore in our opinion it is quite clear that the measurements on the plain film correspond quite confidently to the loop of interest and the extent of the fecal impaction, even though partially affected technical limits of an exam performed in casualty with the patient lying down, in so much as the radiographer was unable to fit the whole abdomen image in the same film. Figure 3 clearly confirmed lately the great extent of the huge fecal impaction. If you doubt please state precisely which one is the doubtful measurement and give the details of your evaluation and opinion about it.
Lastly but least, when you give suggestions and opinion about the opportunity of "taking this kind of patients, not uncommonly seen in general hospitals, directly to your MDCT's" and stating "but we must move on, and accept and promote the use of more efficient imaging tests", remember that probably more than two third of the patients in the world and of the physicians working in the third world countries, does not even have access or only a limited access to CT scan or MDCT.
Dr. Salomone Di Saverio MD

No competing interests declared.