Cross-sectional CT is used in assessment of acute small bowel diseases due to its advantages over the conventional imaging modalities; it assesses the small bowel lumen and wall, surrounding mesentery as well as other abdominal organs. CT is a useful imaging modality in acute setting. Also, the high spatial resolution of CT making it a good modality for achieving better anatomical details [9].
The current study was carried out on 38 patients presented clinically with acute abdominal pain secondary to already known or suspected small bowel origin. There were 23 male and 15 females. The age of involved patients ranges from 4 to 88 years with mean age of incidence about 48 years. No specific considerations regarding the age and sex.
The studied patients are diagnosed as the following: 13 patients with history of pathologically proved inflammatory bowel disease, 12 patients diagnosed with small bowel obstruction, eight patients diagnosed with mesenteric vascular occlusion, four patients diagnosed with perforated bowel and one patient diagnosed with specific small bowel infection (TB).
The inflammatory bowel diseases are the most frequent cause of acute abdominal pain secondary to small bowel origin which agreed by Bassiouny et al. [10] and Shokralla et al. [11].
Our results stated that the small bowel obstruction was the second frequent cause of acute abdominal pain secondary to small bowel origin followed by mesenteric vascular occlusion and infectious bowel disease, respectively, which in agreement with Bassiouny et al. [10] and in disagreement with Shokralla et al. [11] who stated that the mesenteric vascular occlusion is the second frequent cause of acute abdominal pain secondary to small bowel origin. Different sample size of involved patients may contribute in such disagreement.
CT entero-colonography showing signs of active inflammatory bowel changes in 12 patients and only one patient is missed by CTE giving about 92.3% sensitivity of CTE in detection of acute inflammatory changes in patients with history of pathologically proved Crohn’s disease.
The high sensitivity of CTE in our study (more than 90%) in detection of Crohn’s disease acute inflammatory signs was matched with Furukawa et al. [12] and Santos et al. [13] who stated the sensitivity of CTE is over 90%, while Sharma et al. [14], Haas et al. [15] and Monib et al. [16] stated lower sensitivity of CTE (less than 90%) about 83–86% which is lower than our results. This explained by different sample size and wide variety of included small bowel pathologies in our study as Sharma et al. [14] studied the difference imaging features between the Crohn’s disease and intestinal tuberculosis, while Haas et al. [15] and Monib et al. [16] studied only the imaging features of Crohn’s disease.
Mural thickening, mucosal hyper-enhancement and submucosal edema coupled with surrounding fat stranding were the most frequent inflammatory signs seen among patients with Crohn’s disease that denoting acute exacerbation. This is in confirmed by Kilcoyne et al. [8], Athanasakos et al. [3] and Monib et al. [16].
Skip lesions followed by Comb sign, enlarged mesenteric lymph nodes, inflammatory stricture, abscess formation and finally fistulae formation, respectively, were the second frequent signs seen among the Crohn’s disease patients after aforementioned most common signs, Monib et al. [16] stated that. However, our results are in disagreement with Monib et al. [16], the second frequent signs among our results respectively are Comb signs, enlarged lymph nodes, fistulae formation, skip lesions, abscess formation and finally inflammatory stricture. Such mismatching may explained by different sample size.
The current study showed that the most common involved part of small bowel by Crohn’s disease is ileum (83.3%) followed by combined involvement of ileum and duodenum as well as ileum and jejunum which are equally presented (8.3%). This is more or less in agreement with Kilcoyne A et al. [8] and Santos et al. [13].
Raman et al. [17] and Monib et al. [16] stated that bilateral symmetrical sacroiliitis is the most common extra-intestinal osseous manifestations of Crohn’s disease. This matching with our results in that two patients among the examined cases are suffering from bilateral sacroiliitis which is the only noted osseous finding of Crohn’s disease.
Bassiouny et al. [10] stated that TB enteritis is the most frequent cause of infectious small bowel disease which more or less matching with our results, as the only included patient suffering from infectious small bowel disease diagnosed by TB enteritis.
MDCT plays an important role in diagnosis and differentiation between different diseases that affect the small bowel. The CT features of the examined patient showed homogeneous mural enhancement of the terminal ileum and cecum without mural stratification coupled with characteristic necrotic lymph nodes, mild free intra-peritoneal fluid collection and lung involvement. Those signs achieved by usage of CT help in differentiating TB enteritis from Crohn’s disease that usually affect the terminal ileum. Mural stratification pattern of enhancement, skip lesions, multi-segmental involvement of small bowel, frequent associated fistulae and abscess formation with the absence of free intra-peritoneal fluid collection that in favor with Crohn’s disease. This is confirmed by Sharma et al. [14].
Twelve patients among the examined patients are diagnosed with intestinal obstruction, only one of them diagnosed with adhesive intestinal obstruction managed by follow up that show total resolution of the symptoms after one day of treatment. The others are successfully diagnosed by CECT which reflecting high sensitivity of CT in the diagnosis of IO. Silva et al. [18], Elsayed et al. [19] and Paulson et al. [5] are matching with our results as they stated that MDCT has high sensitivity to diagnose small bowel obstruction reaching up to 100%.
The main diagnostic feature of mechanical intestinal obstruction is small bowel dilatation of the obstructed bowel loops (> 2.5 cm) with distal collapse loops is which is seen in all examined patients. Mian et al. [20], Silva et al. [18] and Millet et al. [21] stated that the dilation of small bowel obstruction is the main diagnostic criterion in diagnosis of small bowel obstruction which is matching with our study.
Searching for the site of transition zone helps in identification of the cause of obstruction. Adhesive intestinal obstruction representing the most frequent cause of small bowel obstruction among the examined patients (58.3%) than obstructed hernia. This is in agreement with Mian et al. [20], Paulson et al. [5], Silva et al. [18], Taydas et al. [22] and Elsayed et al. [19] as the increasing rate of operative interference as well as early diagnosis and management of hernia help in making the adhesive small bowel obstruction more frequent cause of small bowel obstruction rather than hernia.
Previous surgical operation plays an important role in development of adhesive bands as post-operative sequence which leading to small bowel obstruction. There are seven patients diagnosed with adhesive intestinal obstruction; five patients (71.5%) have previous abdominal surgical intervention, while two patients have no previous surgical history. Mian et al. [20] and Elsayed et al. [19] stated that post-operative adhesions are responsible of adhesive small bowel obstruction in 70% and 75% of their examined patients, respectively, which is matching with our results.
Other causes of small bowel obstruction through our studied patients are obstructed hernia, intussusception and gall stone ileus which are equally represented. This is in disagreement with Paulson et al. [5] and Taydas et al. [22] who stated that hernia and small bowel cancer are the second frequent causes of small bowel obstruction, while intussusception and gall stone ileus are less common. Our study included most of causes of acute abdomen secondary to small bowel origin which affect the sample size of the examined obstructed patients. This may affect our results and leading to such disagreement.
Silva et al. [18] stated that pneumobilia, ectopic gall stone and small bowel obstruction are the diagnostic triad of gall stone ileus which is matching with our result as one of our patients diagnosed with gall stone ileus due the presence of three important CT signs; pneumobilia, ectopic gall stone and dilated small bowel.
Through our study, CT shows high sensitivity of the diagnosis of mesenteric bowel ischemia which confirmed by surgical intervention in 100% of patients. Kanasaki et al. [2], Moschetta et al. [23] and Furukawa et al. [24] who stated mild lower sensitivity of CT in assessment of mesenteric ischemia averaging 90–96%, this mismatching may referred to different sample size and different studied patient as in our study we involve other cause of acute small bowel diseases.
Acute mesenteric ischemia due to venous thrombosis was the most frequent cause of small bowel ischemia among the examined patients, while the arterial occlusion was the second frequent cause. This is in disagreement with Kanasaki et al. [2], Moschetta et al. [23] Furukawa et al. [24] and Sugi et al. [1].
While Hefny et al. [25] and Wong et al. [26] are matching with our results as they stated that superior mesenteric vein thrombosis is more frequent than superior mesenteric artery occlusion. We attributed the high frequency of superior mesenteric vein thrombosis in comparison with superior mesenteric artery occlusion through the studied cases to associated liver cirrhosis in MVT patients as predisposing factor of thrombosis which seen in three patients while seen only in one patient diagnosed with superior mesenteric artery occlusion. Also, sample size may contribute in such disagreement.
Florim et al. [27], Kanasaki et al. [2], Copin et al. [28] and Furukawa et al. [24] stated that mural thickening is the most frequent small bowel finding in patients diagnosed with acute mesenteric ischemia, while other noted finding such as mesenteric fat stranding, dilated bowel loops and absent mural enhancement are associated with ischemic bowel diseases but with lower frequencies. This is in agreement with our results as the mural thickening was the most frequent small bowel finding.
Mesenteric vessel filling defect noticed in all examined patients which is a high sensitive CT sign for diagnoses of acute mesenteric ischemia. This is in agreement with Florim et al. [27] and Kanasaki et al. [2].
The perforated peptic ulcer was the most common cause of perforated small bowel disease representing about (50%) of examined patients. This is matching with Kim et al. [29], Furukawa et al. [30] and Pouli et al. [31].
Traumatic bowel perforation is the second frequent cause of small bowel perforation representing about (25%) of examined patients. Pouli et al. [31] agree with our results as he stated that traumatic small bowel perforation is the second frequent cause of small bowel perforation, while Kim et al. [29] and Furukawa et al. [30] stated that necrotic and ulcerated malignancies are the second frequent cause of small bowel perforation. This mismatching with our results may explained by small sample size and wide variations of acute small bowel pathologies among our studies patients.
Pneumoperitoneum was the most frequent sign seen among the examined cases as it helps in identification of the site of perforation. The examined cases having perforated peptic ulcer showing foci of pneumoperitoneum closely related to the site of perforation. This is in agreement with Kim et al. [29], Furukawa et al. [30] and Pouli et al. [31].
The distribution of pneumoperitoneum through the abdomen is seen at the sub-phrenic space in two patients including the porta-hepatis in one of them as well as seen scattered through the mesentery in two patients which help in identification of the site of perforation. The associated free intra-peritoneal fluid collection as well as abscess formation close to the site of perforation beside the pneumoperitoneum help also in identification of the site of perforation. This is matching with H. Toprak et al. [32], Kim et al. [29] and Pouli et al. [31].
Limitations
Limitations were encountered in our study:
Wide variations of included pathologies (inflammatory small bowel diseases, SB obstruction, mesenteric ischemia and small bowel perforation) which affect the sample size in each pathological entity.
Larger number of patients may be of value in achieving better statistical analysis.