CT findings of small bowel strangulation: the importance of contrast enhancement. Emerg Radiol. 2013;20:3-9. [PMID: 22910982 DOI: 10.1007/s10140-012-1070-z]

[Postoperative Imaging Findings of Colorectal Surgery: A Pictorial Essay]

Postoperative colorectal imaging studies play an important role in the detection of surgical complications and disease recurrence. In this pictorial essay, we briefly describe methods of surgery, imaging findings of their early and late complications, and postsurgical recurrence of cancer and inflammatory bowel disease.

A late presentation of a left paraduodenal hernia in an elderly patient admitted in emergency: A case report

Small bowel internal hernias (IHs), a rare cause of small bowel occlusion (SBO) and small bowel strangulation, while more commonly seen in young adults, can also affect elderly patients and pose a significant diagnostic challenge due to their nonspecific symptoms. In most cases, laparotomy was used to diagnose IHs. However, multidetector computed tomography (MDCT) is usually the best imaging tool to use in the emergency setting for the diagnosis of IHs. An 83-year-old man was admitted to emergency with acute abdominal pain and a coffee-ground vomitus. The abdominal MDCT showed a clustered-like appearance of proximal jejunal loops at the level of the Treitz ligament with the absence of transit of the medium water-soluble iodine oral contrast agent (Gastrografin). Mesenteric edema was also present with initial suffering of the intestinal wall. A left paraduodenal hernia (LPDH) with strangulation was suspected following the radiological report. The emergency laparotomy revealed about 20 cm of proximal jejunal loops herniated through a 3 cm wide hernia orifice (HO) along the Treitz ligament, at the level of Landzert fossa, located in the confluence of the descending mesocolon, posterior to the inferior mesenteric vein (IMV) and confirming the LPDH. The patient was discharged in good condition some days later. IHs do not have sufficient coverage in literature, especially in cases regarding elderly patients, however, they can be a cause of SBO in people older than 80 years of age. Radiologists and surgeons should be aware of the anatomical aspects of the IHs.

Prediction of bowel necrosis by reduced bowel wall enhancement in closed-loop small bowel obstruction: Quantitative methods

PURPOSE

To assess diagnostic performance and reproducibility of reduced bowel wall enhancement evaluated by quantitative methods using CT to identify bowel necrosis among closed-loop small bowel obstruction (CL-SBO) patients.

METHODS

This retrospective single-center study included patients who diagnosed with CL-SBO caused by adhesion or internal hernia during January 2016 and May 2022. Patients were divided into necrotic group (n = 41) and non-necrotic group (n = 67) according to surgical exploration and postoperative pathology. Two doctors independently measured the attenuation of bowel wall and consensus was reached through panel discussion with a third gastrointestinal radiologist. Reduced bowel wall enhancement was assessed by four quantitative methods. Univariate analyses were used to evaluate the association between each method and bowel necrosis, and kappa/intraclass correlation coefficient values were used to assess interobserver agreement. Diagnostic performance parameters were calculated for each method.

RESULTS

Reduced bowel wall enhancement in arterial phase (OR 8.98, P < 0.0001), reduced bowel wall enhancement in portal phase (OR 16.84, P < 0.001), adjusted reduced bowel wall enhancement in arterial phase (OR 29.48, P < 0.001), adjusted reduced bowel wall enhancement in portal phase (OR 145.69, P < 0.001) were significantly associated with bowel necrosis. Adjusted reduced bowel wall enhancement in portal phase had the best diagnostic performance (AUC: 0.92; Youden index: 0.84; specificity: 94.03 %) and interobserver agreement (kappa value of 0.59-0.73) to predict bowel necrosis.

CONCLUSION

When assessing reduced bowel enhancement to predict bowel necrosis among CL-SBO patients, using unenhanced CT images and proximal dilated loop as standard references in portal phase is the most accurate quantitative method among those tested.

Imaging of abdominopelvic oncologic emergencies

With advancements in cancer treatment, the survival rates for many malignancies have increased. However, both the primary tumors and the treatments themselves can give rise to various complications. Acute symptoms in oncology patients require prompt attention. Abdominopelvic oncologic emergencies can be classified into four distinct categories: vascular, bowel, hepatopancreatobiliary, and bone-related complications. Radiologists need to be familiar with these complications to ensure timely diagnosis, which ultimately enhances patient outcomes.

Unenhanced CT-based predictive model to identify small bowel necrosis in patients with mechanical small bowel obstruction

OBJECTIVES

To investigate the diagnostic value of unenhanced CT in mechanical small bowel obstruction (SBO) with small bowel necrosis, and to establish a predictive model.

METHODS

From May 2017 to December 2021, the patients with mechanical SBO admitted to our hospital were retrospectively collected. Taking pathology-confirmed small bowel necrosis as the gold standard, the experimental group was composed of patients with small bowel necrosis confirmed by pathology, and the control group was composed of patients with no intestinal necrosis confirmed by surgery or successful conservative treatment with no recurrence of intestinal obstruction during 1-month followed-up.

RESULTS

A total of 182 patients were enrolled in this study, 157 patients underwent surgery, of which 35 patients were accompanied with small bowel necrosis and 122 patients were not (33 patients with ischemic findings at surgery without necrosis). Finally, there were 35 patients in the experimental group and 147 patients in the control group. Multivariable logistic regression showed that increased attenuation of small bowel wall (P = 0.002), diffuse mesenteric haziness (P = 0.010), difference of CT value between mesenteric vessel and aorta (P = 0.025) and U-/C-shaped small bowel loop (P = 0.010) were independent risk factors for the diagnosis of mechanical SBO with small bowel necrosis. Through internal verification, the area under curve (AUC) of the predictive model reached 0.886 (95%CI: 0.824-0.947), and the calibration result was moderate.

CONCLUSION

Multiple features (increased attenuation of small bowel wall; difference of CT values between mesenteric vessel and aorta; diffuse mesenteric haziness; and U-/C-shaped small bowel loop) of unenhanced CT have clinical value in the diagnosis of mechanical SBO with small bowel necrosis. The predictive model based on these four features could achieve satisfactory efficiency.

Hypoattenuated Area at Pancreatojejunostomy Site After Pancreatoduodenectomy Predicts Grade B/C Postoperative Pancreatic Fistula

BACKGROUND

After pancreatojejunostomy for pancreatic head resection, contrast-enhanced computed tomography sometimes reveals a hypoattenuated area at the pancreatojejunostomy site. The clinical impact of this hypoattenuated area, in terms of postoperative pancreatic fistula, is unknown.

METHODS

Among 309 patients undergoing pancreatic head resection with pancreatojejunostomy reconstruction at Osaka University Hospital from 2012 to 2020, 105 exhibited drain amylase levels over 3× the upper limit of normal. According to contrast-enhanced computed tomography on postoperative days 3-14, these patients were divided into two groups-evident hypoattenuated area group (≥ 5 mm; n = 46) and subtle hypoattenuated area group (< 5 mm; n = 59)-and evaluated for clinically relevant pancreatic fistula.

RESULTS

Clinically relevant pancreatic fistula was significantly more common with the evident hypoattenuated group (80.4%; 37/46) than the subtle hypoattenuated group (40.7%; 24/59) (P < 0.0001). Multivariate analysis identified four factors related to clinically relevant pancreatic fistula formation: male sex (P = 0.0230), main pancreatic duct diameter < 3 mm (P = 0.0007), operative time > 475 min (P = 0.0161), and evident hypoattenuated area group (P = 0.0050). Hypoattenuated area ≥ 5 mm was associated with clinically relevant pancreatic fistula (60.7% sensitivity; 79.6% specificity).

CONCLUSION

Evident hypoattenuated area on postoperative contrast-enhanced computed tomography was an independent risk factor for clinically relevant pancreatic fistula. Patients experiencing increased drain amylase levels may benefit from contrast-enhanced computed tomography assessment to predict clinically relevant pancreatic fistula formation.

An Update on Acute Mesenteric Ischemia

Acute mesenteric ischemia (AMI) is an uncommon yet highly lethal cause of acute abdomen in the emergency setting. Computed tomography (CT) imaging, in particular a biphasic protocol consisting of angiographic and venous phase scans, is widely used to corroborate non-specific clinical findings when suspicions of AMI are high. Techniques such as low kilovoltage peak scanning, dual energy acquisition, or a combined arterial/enteric phase can improve iodine conspicuity and evaluation of bowel enhancement. Biphasic CT with CT angiography is mandatory to directly assess for the 3 primary etiologies of AMI-arterial, venous, and non-occlusive mesenteric ischemia (NOMI), and the CT angiographic findings may be the first visible in the disease. In addition, numerous non-vascular CT findings have also been reported. Bowel wall thickening, mesenteric stranding, and ascites are common but non-specific findings that correlate poorly with disease severity. Pneumatosis intestinalis and portomesenteric venous gas, while not pathognomonic for ischemia, are highly specific in cases of high clinical suspicion. Bowel wall hypoenhancement is an early and specific sign but requires a protocol optimizing iodine conspicuity to confidently identify. Finally, intraperitoneal free air and solid organ infarcts are also highly specific ancillary findings in AMI. AMI occurs as a complication in 10% of small bowel obstruction (SBO) patients, and understanding imaging findings of ischemia in the context of SBO is necessary to aid in treatment planning and reduce over- and under-diagnosis of strangulation. Familiarity with the imaging features of ischemia by radiologists is vital to establish an early diagnosis before irreversible necrosis occurs.

Prediction and management of strangulated bowel obstruction: a multi-dimensional model analysis

BACKGROUND

Distinguishing strangulated bowel obstruction (StBO) from simple bowel obstruction (SiBO) still poses a challenge for emergency surgeons. We aimed to construct a predictive model that could distinctly discriminate StBO from SiBO based on the degree of bowel ischemia.

METHODS

The patients diagnosed with intestinal obstruction were enrolled and divided into SiBO group and StBO group. Binary logistic regression was applied to identify independent risk factors, and then predictive models based on radiological and multi-dimensional models were constructed. Receiver operating characteristic (ROC) curves and the area under the curve (AUC) were calculated to assess the accuracy of the predicted models. Via stratification analysis, we validated the multi-dimensional model in the prediction of transmural necrosis both in the training set and validation set.

RESULTS

Of the 281 patients with SBO, 45 (16.0%) were found to have StBO, while 236(84.0%) with SiBO. The AUC of the radiological model was 0.706 (95%CI, 0.617-0.795). In the multivariate analysis, seven risk factors including pain duration ≤ 3 days (OR = 3.775), rebound tenderness (OR = 5.201), low-to-absent bowel sounds (OR = 5.006), low levels of potassium (OR = 3.696) and sodium (OR = 3.753), high levels of BUN (OR = 4.349), high radiological score (OR = 11.264) were identified. The AUC of the multi-dimensional model was 0.857(95%CI, 0.793-0.920). In the stratification analysis, the proportion of patients with transmural necrosis was significantly greater in the high-risk group (24%) than in the medium-risk group (3%). No transmural necrosis was found in the low-risk group. The AUC of the validation set was 0.910 (95%CI, 0.843-0.976). None of patients in the low-risk and medium-risk score group suffered with StBO. However, all patients with bowel ischemia (12%) and necrosis (24%) were resorted into high-risk score group.

CONCLUSION

The novel multi-dimensional model offers a useful tool for predicting StBO. Clinical management could be performed according to the multivariate score.

Evaluation of ischemia and necrosis in adhesive small bowel obstruction based on CT signs: Subjective visual evaluation and objective measurement

PURPOSE

To investigate the diagnostic performance of CT signs for detecting bowel ischemia and necrosis in adhesive small bowel obstruction(SBO) with subjective and objective methods.

MATERIALS AND METHODS

113 adhesive SBO patients were enrolled and divided into ischemic group (49 cases in necrotic group and 35 cases in reversible ischemic group) and non-ischemic group (29 cases) according to the operation results. Subjective visual assessment of CT signs associated with ischemia and necrosis was performed by two radiologists independently. Elevated unenhanced attenuation and enhancement value of involved bowel wall were objectively measured and compared by single factor analysis of variance. Cut-off value and diagnostic performance were evaluated by receiver operating characteristic curve (ROC).

RESULTS

Closed-loop mechanism, reduced bowel wall enhancement, and mesenteric edema were associated with bowel ischemia, with sensitivity of 81.0%, 65.5%, 75.0%, and specificity of 86.2%, 96.6%, 89.7%, respectively. Increased unenhanced bowel wall attenuation was a specific sign for necrosis with 100.0% specificity and 51.0% sensitivity. The sensitivity and specificity for ischemia were 86.0% and 91.9% with cut-off enhancement value lower than 33.5 HU. The sensitivity and specificity for necrosis were 58.2% and 100.0% with cut-off elevated unenhanced attenuation higher than 16.5 HU, 86.7% and 83.3% with cut-off enhancement value lower than 21.5 HU.

CONCLUSION

Reduced bowel wall enhancement and increased unenhanced bowel wall attenuation were good indicators of bowel ischemia and necrosis. The objective measurement of elevated unenhanced attenuation and enhancement value can predict bowel ischemia and necrosis more accurately.

Sex differences in non-strangulated postoperative adhesive small bowel obstruction: A retrospective cohort study

BACKGROUND

Adhesive small bowel obstruction (ASBO) is one of the major causes of postoperative morbidity. Non-surgical management is generally applied to non-strangulated ASBO. Several factors have been reported to affect the response to non-surgical management in patients with ASBO. However, the association between sex differences and non-strangulated ASBO remains unclear. This study aimed to elucidate the effect of sex differences in non-strangulated postoperative ASBO.

METHODS

We divided 139 patients with a first episode of non-strangulated postoperative ASBO into two groups: male group (n = 83) and female group (n = 56). Clinical features and prognosis were compared between the two groups.

RESULTS

Female patients had lower proportions of oesophageal/gastric malignancies (P = 0.044) and colorectal malignancies (P = 0.030) and a higher proportion of uterine/ovarian malignancies (P < 0.001) than male patients did. More female patients required surgical management than male patients (P = 0.003) did. Hospital length of stay (LOS) was longer (P = 0.046) in the female group than in the male group. Multiple logistic regression analysis showed that the female sex was associated with an increased risk of the need for surgical management (odds ratio 5.318, P = 0.006). Cox proportional hazards regression analysis revealed that the female sex was positively associated with increased LOS (hazard ratio 0.687, P = 0.045).

CONCLUSION

Female sex was associated with failure of non-surgical management and increased LOS in patients with non-strangulated postoperative ASBO.

Correlation of CT findings with intra-operative outcome in closed-loop small bowel obstruction (CL-SBO)

PURPOSE

To correlate CT-findings in patients with closed-loop small bowel obstruction (CL-SBO) with perioperative findings, to identify patients who require immediate surgical intervention. Secondary purpose was to substantiate the role of radiologists in predicting perioperative outcome.

METHODS

Data were retrospectively obtained from patients with surgically confirmed CL-SBO, between September 2013 and September 2019. Three radiologists reviewed CTs to assess defined CT features and predict patient outcome for bowel wall ischemia and necrosis using a likelihood score. Univariate statistical analyses were performed and diagnostic performance parameters and interobserver agreement were assessed for each feature.

RESULTS

Of 148 included patients, 28 (19%) intraoperatively had viable bowel and 120 (81%) had bowel wall ischemia or necrosis. Most CT characteristics, as well as the likelihood of ischemia and necrosis, found fair or moderate multirater agreement. Increased attenuation of bowel wall and mesenteric vessels on non-contrast-enhanced CT had a specificity for bowel ischemia or necrosis of 100% (sensitivity respectively 48% (p < 0.001) and 21% (p = 0.09)). Mesenteric edema had high sensitivity for ischemia or necrosis (90%), but specificity of only 26% (p < 0.001). For mesenteric fluid, sensitivity was 60% and specificity 57% (p = 0.004). Decreased enhancement of bowel wall in both arterial and PV-phase showed significant correlation, respectively a sensitivity of 58% and 42%, and specificity of 88% and 79% (both p < 0.001). Likelihood of both ischemia and necrosis were significantly correlated with perioperative outcome (p < 0.001).

CONCLUSION

CT findings concerning mesenteric and bowel wall changes, as well as radiologists' judgement of likelihood of ischemia and necrosis are significantly correlated with perioperative outcome of bowel wall ischemia and necrosis in patients with CL-SBO.

Computed Tomography in Emergency Diagnosis and Management Considerations of Small Bowel Obstruction for Surgical vs. Non-surgical Approach

BACKGROUND

Small bowel obstruction (SBO) accounts for 15% of abdominal pain complaints referred to emergency departments and imposes significant financial burdens on the healthcare system. The absence of passage of flatus or stool and abdominal distention are reported as the most common symptom and a sign of SBO, respectively. Patients who do not demonstrate severe clinical or imaging findings are typically treated with conservative approaches. Patients with clinical signs of sepsis or physical findings of peritonitis are often instantly transferred to the operating room without supplementary imaging assessment. However, in cases where symptoms are non-specific, or the physical examination is challenging, such as in cases with loss of consciousness, the diagnosis can be complicated. This paper discusses the key findings detectable on Computed tomography (CT), which are vital for the emergent triage, proper treatment, and decision making in patients with speculated SBO.

METHOD

Narrative review of the literature.

RESULTS AND CONCLUSION

CT plays a key role in emergent triage, proper treatment, and decision making. It provides high sensitivity, specificity, and accuracy in the detection of early-stage obstruction and acute intestinal vascular compromise. It can also differentiate between various etiologies of this entity which is considered an important criterion in the triage of patients into surgical vs. non-surgical treatment. There are multiple CT findings, such as mesenteric edema, lack of the small-bowel feces, bowel wall thickening, fat stranding in the mesentery, and intraperitoneal fluid, which are predictive of urgent surgical exploration.

Ultrasonic Diagnosis of Intestinal Loop Obstruction After Introducing Loop Syndrome After Subtotal Gastrectomy

In this paper, a graphical diagnosis of intestinal loop obstruction input into the loop syndrome after subtotal gastrectomy based on ultrasound diagnosis is more fluid accumulating in the bridge loop. The pressure in the intestinal loop is constantly rising, causing bile and pancreatic juice excretion disorder, and dilation of intrahepatic and external bile ducts or dilation of pancreatic ducts, which is similar to the anatomical features of low biliary obstruction. For dilated bowel, the expansion of the upstream drainage pipe organ changes in physiological and pathological anatomy pathological bridge loop obstruction. The ultrasound can show good and on the ming stomach ultrasound pictures of patients with loop syndrome after major resection were analyzed. Most patients with hepatic shape changed the left hepatic duct dilatation, and the inner diameter is 4.8 cm and the length is 18.0 cm. The wall of the tube is a multi-layer structure, and fold-like echoes can be seen. The lumen does not pass through the angle between the superior mesenteric artery and the abdominal aorta. Patients with a history of pancreas Whillp or Child type surgery or a history of Roux-en-Y type biliary jejunum have clinical manifestations of bowel obstruction. The ultrasound of their bridge loop obstruction showed a long tubular anechoic dark area in the upper abdomen and dilation of the upstream drainage organ duct.

A novel discriminant formula for the prompt diagnosis of strangulated bowel obstruction

PURPOSES

The diagnosis of strangulated bowel obstruction (SBO) is sometimes difficult. We attempted to create and verify a discriminant formula for use as a diagnostic aid for the early diagnosis of SBO.

METHODS

This retrospective study included 97 patients who underwent an operation for SBO from January 2007 to September 2018. First, a discriminant analysis was performed for 73 patients who underwent an operation from January 2007 to December 2015 in order to obtain a formula. Next, we analyzed 34 patients who underwent an operation from January 2016 to September 2018 to verify the formula.

RESULTS

The risk factors for SBO included ascites, signs of preperitoneal irritation, and lactate > 1.16 mmol/L. The discriminant formula is as follows: 1.954 × collection of ascites (1 or 0) + 1.239 × peritoneal irritation sign (1 or 0) + 0.378 × lactate - 2.331 (1: positive, 0: negative). The predictive value was as follows: sensitivity, 87.5%; specificity, 64.7%; and predictive accuracy, 73.5%. In patients who presented within 24 h of the onset, the sensitivity was 92.3%, the specificity was 75.0%, and the predictive accuracy was 85.7%.

CONCLUSION

Our discriminant formula seems useful for the rapid diagnosis of SBO.

Predicting Intestinal Ischaemia in Patients with Adhesive Small Bowel Obstruction: A Simple Score

BACKGROUND/AIMS

Intestinal ischaemia (II) is the most critical factor to determine in patients with adhesive small bowel obstruction (ASBO) because intestinal ischaemia could be reversible. The aim of this study was to create a clinicoradiological score to predict II in patients with ASBO.

METHODS

We conducted a retrospective study including 124 patients with ASBO. Logistic regression analysis was used to identify predictive factors of II. We assigned points for the score according to the regression coefficient. The area under the curve (AUC) was determined using receiver operating characteristic curves.

RESULTS

Six independent predictive factors of II were identified: age, pain duration, body temperature, WBC, reduced wall enhancement and segmental mesenteric fluid at CT scan. According to the regression, coefficient points were assigned to each of the variables associated with II. The estimated rates of II were calculated for the total scores ranging from 0 to 24. The AUC of this clinicoradiological score was 0.92. A cut-off score of 6 was used for the low-probability group (the risk of II was 1.13%). A score ranging from 7 to 15 defined intermediate-probability group (the risk of II was 44%). A score ≥16 defined high-probability group (100% of patients in this group had II).

CONCLUSIONS

We performed a score to predict the risk of intestinal II with a good accuracy (the AUC of our score exceeded 0.90). This score is reliable and reproducible, so it can help surgeon to prioritize patients with II for surgery because ischaemia could be reversible, avoiding thus intestinal necrosis.

Association of feces sign with prognosis of non-emergency adhesive small bowel obstruction

BACKGROUND

/Objective: The feces sign has been reported as a possible predictive factor for non-operative treatment of small bowel obstruction. However, its relationship with prognosis of non-emergency adhesive small bowel obstruction remains unclear. This study aimed to clarify the relationship between the feces sign and prognosis of non-emergency adhesive small bowel obstruction.

METHODS

Ninety-two patients with non-emergency adhesive small bowel obstruction with the transitional zone visible on computed tomography were included. Patients were categorized into two groups: feces sign positive (n = 40) and negative (n = 52). Clinical features and prognosis were compared between the two groups. Cox proportional hazards regression models incorporating the feces sign were used to analyze odds of diet resumption and discharge.

RESULTS

Patients with feces sign were younger (p = 0.015), had a higher body mass index (p = 0.027), and a lower white blood cell count (p = 0.019) on admission. More patients with feces sign were successfully treated with fasting and/or nasogastric tube placement (p < 0.001), and no patient with feces sign suffered from recurrent obstruction after diet resumption. Kaplan-Meier analysis showed that patients with feces sign took less time for diet resumption (p = 0.007) and discharge (p = 0.004) than those without it. Using Cox proportional hazards regression model, the feces sign was reported as an independent predictor of diet resumption (odds ratio 1.685, p = 0.018) and discharge (odds ratio 1.861, p = 0.007).

CONCLUSIONS

The feces sign is associated with improved odds for diet resumption and discharge.

Impact of barometric pressure on adhesive small bowel obstruction: a retrospective study

Background

Adhesive small bowel obstruction (ASBO) is one of the most common causes of postoperative morbidity. According to Boyle’s law, decreased barometric pressure expands the volume of intestinal gas. We aimed to elucidate the relationship between barometric pressure and ASBO.

Methods

We divided 215 admissions of 120 patients with ASBO into three groups: the fasting group, which responded to fasting (n = 51); the decompression group, which was successfully treated with gastrointestinal decompression (n = 104); and the surgery group which required emergency or elective surgery to treat ASBO (n = 60). We compared and examined clinical backgrounds, findings on admission, and barometric pressure during the peri-onset period (29 days: from 14 days before to 14 days after the onset of ASBO).

Results

There were significant differences among the three groups regarding gender, history of ASBO, hospital length of stay, and barometric pressure on the onset day of ASBO. Barometric pressure on the onset day was significantly higher in the fasting group than in the decompression group (p = 0.005). During pre-onset day 5 to post-onset day 2, fluctuations in the barometric pressure in the fasting and decompression groups showed reciprocal changes with a symmetrical axis overlapping the median barometric pressure in Matsumoto City; the fluctuations tapered over time after onset. In the fasting group, the barometric pressure on the onset day was significantly higher than that on pre-onset days 14, 11, 7, 4, 3, and 2; post-onset days 3 and 10; and the median pressure in Matsumoto City. Conversely, in the decompression group, the barometric pressure on the onset day was lower than that on pre-onset days 14, 5–2; post-onset days 1, 2, 7, 8, 11, 13, and 14; and the median pressure in Matsumoto City. In the surgery group, the barometric pressure on the onset day was equivalent to those on the other days.

Conclusions

ASBO with response to conservative treatment is vulnerable to barometric pressure. Additionally, ASBO that is successfully treated with fasting and decompression is associated with a different barometric pressure on the onset day and reciprocal fluctuations in the barometric pressure during the peri-onset period.

Contrast-Enhanced CT for the Diagnosis of Acute Mesenteric Ischemia

OBJECTIVE. The purpose of this article is to provide an overview of the diagnostic and prognostic roles of CT in the management of acute mesenteric ischemia. CONCLUSION. Acute mesenteric ischemia is defined as inadequate blood supply to the gastrointestinal tract resulting in ischemic and inflammatory injury. The prognosis is poor without treatment. Contrast-enhanced CT has become the cornerstone of diagnosis to identify features of vascular disorders and of intestinal ischemic injury and to visualize bowel necrosis.

Surgery for adhesive small-bowel obstruction is associated with improved long-term survival mediated through recurrence prevention: A population-based, propensity-matched analysis

BACKGROUND

Adhesive small-bowel obstruction (aSBO) is among the most common reasons for admission to a surgical service. While operative intervention for aSBO is associated with a lower risk of recurrence, current guidelines continue to advocate a trial of nonoperative management. The impact of the increased risk for recurrence on long-term survival is unknown. We sought to explore the potential for improved survival with operative management through the prevention of admissions for recurrence of aSBO and the associated risks.

METHODS

This is a population-based retrospective cohort study using administrative data. We identified patients admitted to hospital for their first episode of aSBO from 2005 to 2014 and created a propensity-matched cohort to compare survival of patients managed operatively with those managed nonoperatively. To test whether survival differences were mediated by recurrence prevention, a competing risk regression was used to model the subdistribution hazard of death when accounting for the risk of recurrence. An instrumental variable approach was used as a secondary analysis to compare survival while accounting for unmeasured confounding.

RESULTS

There were 27,904 patients admitted for their first episode of aSBO between 2005 and 2014. The mean age was 61.2 years (std dev, 13.6), and 51% were female. Operative management was associated with a significantly lower risk of death (hazard ratio, 0.80; 95% confidence interval, 0.75-0.86), which was robust to instrumental variable analyses, and a lower risk of recurrence (hazard ratio, 0.59; 95% confidence interval, 0.54-0.65). When adjusting for the risk of recurrence, operative intervention was not associated with improved survival, suggesting that the survival benefit is mediated through prevention of recurrences of aSBO.

CONCLUSION

In patients admitted for their first episode of aSBO, operative intervention is associated with a significant long-term survival benefit. This survival benefit appears to be mediated through the prevention of recurrences of aSBO.

STUDY TYPE

Retrospective cohort study.

LEVEL OF EVIDENCE

Therapeutic study, Level II.

Internal hernia as one of the causes of abdominal pain

Abdominal pain is often observed in clinical practice, causing diagnostic difficulties for doctors of different specialties. Internal hernias are a surgical pathology and may be the cause for the development of acute small bowel obstruction and the occurrence of pain. A modern classification of internal hernias is presented and their topographic-anatomical description is given. The analysis of the results of computed tomography (CT) scan of the abdominal cavity in 20 patients with an unidentified cause of abdominal pain was performed. According to the CT data, three patients had internal hernias that caused the development of pain syndrome. A pathological displacement of intestinal loops with partial disruption of intestinal permeability and curvature of the mesentery without critical disturbance of blood supply was demonstrated in 4 patients with abdominal pain. The findings suggest that CT may be the method of choice when examining patients with an unknown cause of abdominal pain syndrome.

Small Bowel Obstruction

Identifying patients with small bowel obstruction who need operative intervention and those who will fail nonoperative management is a challenge. Without indications for urgent intervention, a computed tomography scan with/without intravenous contrast should be obtained to identify location, grade, and etiology of the obstruction. Most small bowel obstructions resolve with nonoperative management. Open and laparoscopic operative management are acceptable approaches. Malnutrition needs to be identified early and managed, especially if the patient is to undergo operative management. Confounding conditions include age greater than 65, post Roux-en-Y gastric bypass, inflammatory bowel disease, malignancy, virgin abdomen, pregnancy, hernia, and early postoperative state.

Pericecal herniation of sigmoid colon diagnosed by computed tomography: Two case reports

INTRODUCTION

Computed tomography (CT) plays an important role in diagnosing specific types of internal hernias and their complications. In particular, pericecal hernia of the sigmoid colon has never been reported in the English literature.

CASE PRESENTATION

The first patient was a 46-year-old female presented to our institution due to acute abdominal pain. The second patient was a 55-year-old male presented to our institution with continuous diarrhea. The patient underwent colonoscopy for further evaluation. However, even with sufficient air insufflation and repetitive maneuvers, the colonoscope could not proceed beyond the narrowed level of the sigmoid colon. In both cases, contrast-enhanced abdominal CT was done and a herniated loop of sigmoid colon was noted in the posterolateral aspect of the cecum and ascending colon. Thus, a diagnosis of pericecal herniation of the sigmoid colon was established.

CONCLUSION

This case study indicates that radiologic examination can be helpful in detecting pericecal herniation of the sigmoid colon.

Adhesive internal hernia: multidetector CT findings and clinical relevance

AIM

To review the clinical and multidetector computed tomography (MDCT) features of adhesive internal hernias (IHs) and to ascertain specific MDCT criteria to assist in the diagnosis of adhesive IHs and the early detection of intestinal strangulation.

MATERIALS AND METHODS

Medical records and preoperative abdominal MDCT findings of 34 patients with surgically confirmed abdominal adhesive IHs were analysed retrospectively.

RESULTS

The specific MDCT features of adhesive IHs included the following: dislocating and clustering of intestinal segments (100%); stretching and crowding of the mesenteric vessels (100%); presence of hernial orifice (88.2%), peritoneal adhesive bands (76.5%); and the fat notch sign (85.3%). In addition, the significant MDCT features indicative of intestinal strangulation compared with those without intestinal strangulation were bowel wall thickening (p=0.009), intramural haemorrhage (p=0.007), and abnormal bowel wall enhancement (p=0.023). Furthermore, bowel obstruction occurred in 17 (50%) patients, and mesenteric whirl was apparent in 8 (23.5%) patients.

CONCLUSION

This article illustrates the specific MDCT criteria of adhesive IHs. Knowledge of MDCT findings in adhesive IHs and their complications is essential for making the correct diagnosis and may help guide early clinical management.

CT value of the intestine is useful predictor for differentiate irreversible ischaemic changes in strangulated ileus

PURPOSE

To determine the differential points of strangulated ileus with and without irreversible ischaemic changes, especially on preoperative computed tomography (CT) images.

METHODS

Seventy patients with strangulated ileus underwent emergency operations between January 2009 and July 2016 in our department. Of these patients, 57 met the study requirements, including 30 patients who had irreversible ischaemic changes (ischaemic group; n = 30) and 27 patients who had reversible ischaemic changes during laparotomy (non-ischaemic group; n = 27). We compared the preoperative clinical and radiographic factors between the ischaemic and non-ischaemic groups.

RESULTS

Univariate analysis revealed that a mean CT value of the intestine in an unenhanced image ≥16.5 HU (p < 0.001), a mean CT value ratio of the intestine (enhanced/unenhanced image) <1.5 (p < 0.001), presence of mesenteric fluid (p = 0.002) and presence of free peritoneal fluid (p = 0.009) were associated with the ischaemic group.

CONCLUSIONS

Calculation of the mean CT value of a strangulated intestine may be a useful method for predicting irreversible ischaemic changes in addition to the presence of mesenteric fluid or free peritoneal fluid.

Strangulated small bowel obstruction in children

BACKGROUND

Diagnosing intestinal strangulation as a complication of small bowel obstruction (SBO) remains a considerable challenge in children. We evaluated the clinicoradiological parameters for predicting the presence of a strangulated intestine.

METHODS

We reviewed the medical records of 69 pediatric patients who underwent operation for acute SBO. Regression analysis was used to identify the parameters for predicting strangulated SBO.

RESULTS

Of the 69 patients with SBO, 27 patients had intestinal strangulation and were awarded one point each towards the overall clinical score: intractable continuous abdominal pain, tachycardia, white blood cell count >13,600/mm³, and abdominal distention. Patients with a clinical score ≥2 combined with the presence of ascites in ultrasound (US) results or with wall thickness and reduced wall contrast enhancement in abdominal computed tomography (CT) scans showed strong evidence for intestinal strangulation.

CONCLUSION

The combination of two or more clinical parameters, including intractable continuous abdominal pain, tachycardia, leukocytosis, and abdominal distention with the presence of ascites in US or wall thickness and reduced wall contrast enhancement in, is useful for the identification of strangulated SBO.

THE TYPE OF STUDY AND LEVEL OF EVIDENCE

Prognosis study; Level III.

Assessment of Strangulation in Adhesive Small Bowel Obstruction on the Basis of Combined CT Findings: Implications for Clinical Care

Purpose To determine which computed tomography (CT) findings or combinations of findings can help to accurately identify strangulation in adhesive small bowel obstruction (SBO). Materials and Methods Contrast agent-enhanced CT findings in a cohort of 256 patients consecutively admitted for adhesive SBO, with a delay of less than 24 hours between CT and surgery for the operated patients, were reviewed independently by two radiologists, with consensus by a third, to assess CT findings commonly associated with strangulation. The reference standard for strangulation was surgery. Univariate and multivariate analyses were performed to identify predictors of strangulation in the entire cohort and to identify predictors of the need for surgical resection in the subgroup of patients with strangulation. A CT score was obtained and diagnostic performances of different combined CT findings were calculated. Results In this study, 105 patients (41.0%; 105 of 256) underwent a surgical procedure, 62 of whom were found to have strangulation (59.0%; 62 of 105), whereas 151 patients (59.0%; 151 of 256) improved with medical care. Three CT findings were significantly associated with strangulation in the multivariate analysis: reduced bowel wall enhancement (odds ratio, 7.8; 95% confidence interval [CI]: 2.6, 23.5), diffuse mesenteric haziness (odds ratio, 6.1; 95% CI: 2.5, 15.2), and a closed-loop mechanism (odds ratio, 6.5; 95% CI: 2.8, 15.5). The model combining these three features had an area under the curve of 0.91 (95% CI: 0.86, 0.96) and a high negative predictive value (97%; 95% CI: 93%, 99%). Positive likelihood ratios were high when two or three of these CT findings were combined (positive likelihood ratios, 14.7 [95% CI: 7.1, 30.4] and 43.8 (95% CI: 14.2, 135.2], respectively). Among the strangulated cases, reduced bowel wall enhancement (odds ratio, 3.9; 95% CI: 1.3, 12) and mesenteric fluid (odds ratio, 3.6; 95% CI: 1.0, 12.8) were predictive of resection. Conclusion A score that combines three CT findings (reduced bowel wall enhancement, a closed-loop mechanism, and diffuse mesenteric haziness) can accurately predict strangulation in adhesive SBO. ^© RSNA, 2017 Online supplemental material is available for this article.

Bowel obstruction without history of laparotomy: Clinical analysis of 70 patients

BACKGROUND

Determining the cause of bowel obstruction without a history of laparotomy (BO without HL) is difficult and can result in delay of treatment and development of a potentially life-threatening situation. We herein investigated the clinical characteristics of pediatric patients who underwent laparotomy due to BO without HL.

METHODS

All surgical pediatric patients aged <16 age who were diagnosed with BO without HL between January 2004 and September 2014 were included. Etiology of BO, intraoperative findings and postoperative outcome were investigated retrospectively.

RESULTS

Seventy patients were diagnosed with BO without HL in this period. In these 70 patients, malrotation (n = 34), intussusception (n = 19), internal hernia (n = 6) and Meckel's diverticulum (n = 5) were predominantly identified. Regarding preoperative definitive diagnosis, prevalence of internal hernia, Meckel's diverticulum or idiopathic volvulus was significantly lower than that of malrotation or intussusception (P < 0.05). Intraoperatively, the rates of strangulation and bowel resection were 55.7% and 30.0%, respectively. The optimal time for emergency operation in order to avoid strangulated bowel resection was <19 h from onset of symptoms.

CONCLUSIONS

Malrotation and intussusception are major causes of BO without HL in children, but internal hernia, Meckel's diverticulum and idiopathic volvulus should always be taken into account, particularly because of the preoperative diagnostic difficulty and resulting high rate of intestinal resection. In order to avoid resection of the bowel, surgery should be done within 19 h before bowel ischemic change occurs.

Multi-slice CT for diagnosis of acute mesenteric ischemia

Acute mesenteric ischemia (AMI) has an acute onset and a high mortality rate with nonspecific clinical presentation and is difficult to diagnose. In recent years, due to fast submillimeter scanning and subtle three-dimensional reconstruction, 64-row multi-slice CT can distinctly demonstrate the stenosis and occlusion of the mesenteric vessels, assess the alteration of morphology and blood perfusion of the intestinal wall and mesentery, and promptly and accurately diagnose AMI, intestinal infarction and its etiology. Therefore, CT has become the most valuable and first-line diagnostic modality for evaluating patients with suspected AMI. AMI has different and complicated CT findings due to different etiology, pathology, extent, position, as well as with or without mural hemorrhage or infection. In this article, we systematically review the multi-slice CT manifestations of AMI and its diagnostic value in various causes of AMI in different stages.

Diagnostic Value of Plain and Contrast Radiography, and Multi-slice Computed Tomography in Diagnosing Intestinal Obstruction in Different Locations

Early intestinal obstruction is easily misdiagnosed. Many physicians consider terminal bouton if computed tomography (CT) scan is done. However, different examinations provide diverse information and significance. This retrospective, randomized, clinical study investigated the diagnostic value of three imaging modalities for intestinal obstruction, supine and upright (or decubitus) plain abdominal radiography, contrast radiography using Gastrografin, and 64 multi-slice spiral CT (MSCT). A total 142 patients with intestinal obstruction were examined. The diagnostic accuracy of plain radiography, contrast radiography, and MSCT for detecting small bowel obstruction was 62.5, 85, and 77.5 %, for localizing the obstruction was 0, 90, and 78.75 %, and for determining the cause of obstruction was 0, 71, and 65 %, respectively. The diagnostic accuracy for detecting large bowel obstruction was 53.23, 73.17, and 92 %, and for localizing the obstruction was 38.17, 60.98, and 98 %, respectively. The diagnostic accuracy of MSCT in determining the cause of obstruction was 91 %. None of the patients administered Gastrografin experienced any adverse effects. In conclusion, MSCT has great diagnostic value in identifying the site and cause of intestinal obstruction, especially in cases of large bowel obstruction. Contrast radiography using Gastrografin was effective in diagnosing and treating small bowel obstruction, making it a beneficial adjunct to MSCT.

Assessment of Bowel Wall Enhancement for the Diagnosis of Intestinal Ischemia in Patients with Small Bowel Obstruction: Value of Adding Unenhanced CT to Contrast-enhanced CT

Purpose To determine whether adding unenhanced computed tomography (CT) to contrast material-enhanced CT improves the diagnostic performance of decreased bowel wall enhancement as a sign of ischemia complicating mechanical small bowel obstruction (SBO). Materials and Methods This retrospective study was approved by the institutional review board, which waived the requirement for informed consent. Two gastrointestinal radiologists independently performed retrospective assessments of 164 unenhanced and contrast-enhanced CT studies from 158 consecutive patients (mean age, 71.2 years) with mechanical SBO. The reference standard was the intraoperative and/or histologic diagnosis (in 80 cases) or results from clinical follow-up in patients who did not undergo surgery (84 cases). Decreased bowel wall enhancement was evaluated with contrast-enhanced images then and both unenhanced and contrast-enhanced images 1 month later. Diagnostic performance of decreased bowel wall enhancement and confidence in the diagnosis were compared between the two readings by using McNemar and Wilcoxon signed rank tests. Interobserver agreement was assessed by using κ statistics and compared with bootstrapping. Results Ischemia was diagnosed in 41 of 164 (25%) episodes of SBO. For both observers, adding unenhanced images improved decreased bowel wall enhancement sensitivity (observer 1: 46.3% [19 of 41] vs 65.8% [27 of 41], P = .02; observer 2: 56.1% [23 of 41] vs 63.4% [26 of 41], P = .45), Youden index (from 0.41 to 0.58 for observer 1 and from 0.42 to 0.61 for observer 2), and confidence score (P < .001 for both). Specificity significantly increased for observer 2 (84.5% [104 of 123] vs 94.3% [116 of 123], P = .002), and interobserver agreement significantly increased, from moderate (κ = 0.48) to excellent (κ = 0.89; P < .0001). Conclusion Adding unenhanced CT to contrast-enhanced CT improved the sensitivity, diagnostic confidence, and interobserver agreement of the diagnosis of ischemia, a complication of mechanical SBO, on the basis of decreased bowel wall enhancement. (©) RSNA, 2016.

Bowel Obstruction

Small bowel obstruction and large bowel obstruction account for approximately 20% of cases of acute abdominal surgical conditions. The role of the radiologist is to answer several key questions: Is obstruction present? What is the level of the obstruction? What is the cause of the obstruction? What is the severity of the obstruction? Is the obstruction simple or closed loop? Is strangulation, ischemia, or perforation present? In this presentation, the radiologic approach to and imaging findings of patients with known or suspected bowel obstruction are presented.

Internal Hernias in the Era of Multidetector CT: Correlation of Imaging and Surgical Findings

Clinical diagnosis of internal hernias is challenging because of their nonspecific signs and symptoms. Many types of internal hernias have been defined: paraduodenal, small bowel mesentery-related, greater omentum-related, lesser sac, transverse mesocolon-related, pericecal, sigmoid mesocolon-related, falciform ligament, pelvic internal, and Roux-en-Y anastomosis-related. An internal hernia is a surgical emergency that can develop into intestinal strangulation and ischemia. Accurate preoperative diagnosis is crucial for appropriate management. Multidetector computed tomography (CT), with its thin-section axial images, high-quality multiplanar reformations, and three-dimensional images, currently plays an essential role in preoperative diagnosis of internal hernias. The diagnostic approach to internal hernias at multidetector CT includes detecting an intestinal closed loop, identifying the hernia orifice, and analyzing abnormal displacement of surrounding structures and key vessels around the hernia orifice and hernia sac. At each step, multidetector CT can depict pathognomonic findings. A saclike appearance suggests an intestinal closed loop in several types of internal hernias. Convergence, engorgement, and twisting of mesenteric vessels in the hernia orifice can be seen clearly at multidetector CT, especially with use of multiplanar reformations. For definitive diagnosis of an internal hernia, analysis of displacement of anatomic landmarks around the hernia orifice is particularly important, and thin-section images provide the required information. Detailed knowledge of the anatomy, etiology, and imaging landmarks of the various hernia types is also necessary. Familiarity with the appearances of internal hernias at multidetector CT allows accurate and specific preoperative diagnosis. (©)RSNA, 2015.

Review of small-bowel obstruction: the diagnosis and when to worry

This is a review of small-bowel obstruction written primarily for residents. The review focuses on radiography and computed tomography (CT) for diagnosing small-bowel obstruction and CT for determining complications. (©) RSNA, 2015.

Evaluating for acute mesenteric ischemia in critically ill patients: diagnostic peritoneal lavage is associated with reduced operative intervention and mortality

BACKGROUND

The diagnosis of acute mesenteric ischemia among intensive care unit (ICU) patients continues to be difficult and carries high mortality, and yet, it is essential that it be made expeditiously such that lifesaving operative intervention can be offered. A recent study suggested that computed tomography (CT) scan delays operative intervention. Thus, we hypothesized that diagnostic peritoneal lavage (DPL), a rapidly performed bedside procedure of established high sensitivity, is associated with reduced operative intervention, time to operative intervention, and mortality.

METHODS

We performed a single-institution, retrospective study of 120 patients admitted to an ICU at the University of Pittsburgh Medical Center's Presbyterian Hospital between January 1, 2002, and December 31, 2010, who were diagnosed with acute mesenteric ischemia. We defined a DPL of greater than 500 cells per cubic millimeter as diagnostic of intra-abdominal pathology. CT scan results were categorized as (1) diagnostic of mesenteric ischemia, (2) abnormal, or (3) normal. We performed multivariate logistic regression, adjusting for difference in case mix, to determine whether DPL is associated with the outcomes of mortality and operative intervention.

RESULTS

The cohort was severely ill, with a mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score of 21.7 (range, 0-48), and 51 patients (42.5%) died. The distribution of preoperative evaluation is as follows: CT, 67; DPL, 11; both modalities, 18; and no preoperative evaluation, 24. Those undergoing DPL were more severely ill, as evidenced by significantly higher APACHE II scores. By comparison with CT, DPL was associated with a reduced risk for operation intervention (adjusted odds ratio, 0.04; 95% confidence interval, 0.01-0.32; p = 0.002) and mortality (adjusted odds ratio, 0.09; 95% confidence interval, 0.01-0.62; p = 0.02).

CONCLUSION

DPL is associated with reduced operative intervention yet improved survival, when compared with patients evaluated with either CT or no diagnostic modality. These data support that, for critically ill ICU patients suspected of harboring intra-abdominal pathology such as acute mesenteric ischemia, DPL should be a mainstay in the preoperative diagnostic evaluation. Further investigation is needed, however, to better define the proper place and timing of DPL in evaluating the acute abdomen.

LEVEL OF EVIDENCE

Diagnostic study, level III; therapeutic/care management study, level IV.

Clinicopathological evaluation of anoxic mucosal injury in strangulation ileus

Background

In patients with strangulation ileus, the severity of bowel ischemia is unpredictable before surgery. To consider a grading scale of anoxic damage, we evaluated the pathological findings and investigated predictive factors for bowel gangrene.

Methods

We assessed 49 patients with strangulation ileus who underwent a laparotomy between January 2004 and November 2012. Laboratory tests and the contrast computed tomography (CT) were evaluated before surgery. According to the degree of mucosal degeneration, we classified anoxic damages into the following 3 grades. Ggrade 1 shows mild mucosal degeneration with extended subepithelial space. Grade 2 shows moderate degeneration and mucosal deciduation with residual mucosa on the muscularis mucosae. Grade 3 shows severe degeneration and mucosal digestion with disintegration of lamina propria.

Results

Resected bowel specimens were obtained from the 36 patients with severe ischemia, while the remaining 13 patients avoided bowel resection. The mucosal injury showed grade 1 in 11 cases, grade 2 in 10 cases, and grade 3 in 15 cases. The patients were divided into two groups. One group included grade 1 and non-resected patients (n = 24) while the other included grades 2 and 3 (n = 25). When comparing the clinical findings for these groups, elevated creatine kinase (P = 0.017), a low base excess (P = 0.021), and decreased bowel enhancement on the contrast CT (P = 0.001) were associated with severe mucosal injury.

Conclusion

In strangulation ileus, anoxic mucosal injury progresses gradually after rapid spreading of bowel congestion. Before surgical intervention, creatine kinase, base excess, and bowel enhancement on the contrast CT could indicate the severity of anoxic damage. These biomarkers could be the predictor for bowel resection before surgery.

Usefulness of intestinal fatty acid-binding protein in predicting strangulated small bowel obstruction

BACKGROUND

The level of intestinal fatty acid-binding protein (I-FABP) is considered to be useful diagnostic markers of small bowel ischemia. The purpose of this retrospective study was to investigate whether the serum I-FABP level is a predictive marker of strangulation in patients with small bowel obstruction (SBO).

METHODS

A total of 37 patients diagnosed with SBO were included in this study. The serum I-FABP levels were retrospectively compared between the patients with strangulation and those with simple obstruction, and cut-off values for the diagnosis of strangulation were calculated using a receiver operating characteristic curve. In addition, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated.

RESULTS

Twenty-one patients were diagnosed with strangulated SBO. The serum I-FABP levels were significantly higher in the patients with strangulation compared with those observed in the patients with simple obstruction (18.5 vs. 1.6 ng/ml p<0.001). Using a cut-off value of 6.5 ng/ml, the sensitivity, specificity, PPV and NPV were 71.4%, 93.8%, 93.8% and 71.4%, respectively. An I-FABP level greater than 6.5 ng/ml was found to be the only independent significant factor for a higher likelihood of strangulated SBO (P =  0.02; odds ratio: 19.826; 95% confidence interval: 2.1560 - 488.300).

CONCLUSIONS

The I-FABP level is a useful marker for discriminating between strangulated SBO and simple SBO in patients with SBO.

A spontaneous strangulated transomental hernia: Prospective and retrospective multi-detector computed tomography findings

Transomental hernias are among the rarest type of all internal hernias which overall account for less than 6% of small bowel obstructions. Most transomental hernias occurring in adults are either iatrogenic or post-traumatic. More rarely, a spontaneous herniation of small bowel loops may result from senile atrophy of the omentum. We report a case of an 86-year-old male who presented with signs and symptoms of small bowel obstruction but had no past surgical or traumatic abdominal history. At contrast-enhanced multi-detector row computed tomography (CT), a cluster of fluid-filled dilated small bowel loops could be appreciated in the left flank, with associated signs of bowel wall ischemia. Swirling of the mesenteric vessels could also be appreciated and CT findings were prospectively considered consistent with a strangulated small bowel volvulus. At laparotomy, no derotation had to be performed but up to 100 cm of gangrenous small bowel loops had to be resected because of a transomental hernia through a small defect in the left part of the greater omentum. Retrospective reading of CT images was performed and findings suggestive of transomental herniation could then be appreciated.

Utility of arterial phase of dynamic CT for detection of intestinal ischemia associated with strangulation ileus

AIM: To clarify the usefulness of arterial phase scans in contrast computed tomography (CT) imaging of strangulation ileus in order to make an early diagnosis.

METHODS: A comparative examination was carried out with respect to the CT value of the intestinal tract wall in each scanning phase, the CT value of the content in the intestinal tract, and the CT value of ascites fluid in the portal vein phase for a group in which ischemia was observed (Group I) and a group in which ischemia was not observed (Group N) based on the pathological findings or intra-surgical findings. Moreover, a comparative examination was carried out in Group I subjects for each scanning phase with respect to average differences in the CT values of the intestinal tract wall where ischemia was suspected and in the intestinal tract wall in non-ischemic areas.

RESULTS: There were 15 subjects in Group I and 30 subjects in Group N. The CT value of the intestinal tract wall was 41.8 ± 11.2 Hounsfield Unit (HU) in Group I and 69.6 ± 18.4 HU in Group N in the arterial phase, with the CT value of the ischemic bowel wall being significantly lower in Group I. In the portal vein phase, the CT value of the ischemic bowel wall was 60.6 ± 14.6 HU in Group I and 80.7 ± 17.7 HU in Group N, with the CT value of the ischemic bowel wall being significantly lower in Group I; however, no significant differences were observed in the equilibrium phase. The CT value of the solution in the intestine was 18.6 ± 9.5 HU in Group I and 10.4 ± 5.1 HU in Group N, being significantly higher in Group I. No significant differences were observed in the CT value of the accumulation of ascites fluid. The average difference in the CT values between the ischemic bowel wall and the non-ischemic bowel wall for each subject in Group I was 33.7 ± 20.1 HU in the arterial phase, being significantly larger compared to the other two phases.

CONCLUSION: This is a retrospective study using a small number of subjects; however, it suggests that there is a possibility that CT scanning in the arterial phase is useful for the early diagnosis of strangulation ileus.