Large-bowel obstruction: CT findings, pitfalls, tips and tricks

CT prognostic signs of postoperative complications in emergency surgery for acute obstructive colonic cancer

PURPOSE

To identify CT prognostic signs of poor outcomes in acute obstructive colonic cancer (AOCC).

METHODS

Demographic, clinical, laboratory, radiological and surgical data of 65 consecutive patients with AOCC who underwent emergency surgery were analyzed. CT exams were reviewed to assess diameters of cecum, ascending, transverse, descending, and sigmoid proximal to the tumor; colon segments' CD/L1-VD ratios, continence of the ileocecal valve, small bowel overdistension, presence of small bowel feces sign and cecal pneumatosis. Post Operative complications (PO), according to the Clavien-Dindo classification, were analyzed.

RESULTS

Gender, age and location of the tumor were not predictive factors of complications. Among laboratory exams, CRP was the most important predictive value of PO (OR 8.23). A cecum distension ≥ 9 cm represented the critical diameter beyond which perforation and cecal necrosis were found at surgery. Cecal pneumatosis at CT was correlated with cecal necrosis at surgery in < 50% of patients. Pre-operative transverse colon CD/L1-VD ratio ≥ 1.43 and descending colon CD/L1-VD ratio ≥ 1.31 were associated with the development of PO (grade ≥ III-V). PO (grade ≥ III-V) occurred in 18/65 patients.

CONCLUSION

Postoperative complications in emergency surgery of AOCC were not related to the age, sex and tumor's location. Preoperative PCR values (≥ 2.17) predict the development of postoperative complications. CT resulted a valid diagnostic tool to identify patients at higher risk of complications: a CD/L1-VD ratios with cut-off values of 1.43 (transverse) and 1.31 (descending) predicted major complications (grade ≥ III-V) and a cecum distension ≥ 9 cm represented the critical diameter beyond which perforation occurred in > 84% of patients.

ESR Essentials: Imaging in colorectal cancer-practice recommendations by ESGAR

Colorectal cancer (CRC) is a significant global health concern. Diagnostic imaging, using different modalities, has a pivotal role in CRC, from early detection (i.e., screening) to follow-up. The role of imaging in CRC screening depends on each country's approach: if an organized screening program is in place, the role of CT colonography (CTC) is limited to the study of either individuals with a positive stool test unwilling/unable to undergo colonoscopy (CC) or in patients with incomplete CC. Although CC is the most common modality to diagnose CRC, CRC can be also incidentally detected during a routine abdominal imaging examination or at the emergency room in patients presenting with intestinal occlusion/subocclusion or perforation. Staging is a crucial aspect of CRC management, guiding treatment decisions and providing valuable prognostic information. An accurate local staging is mandatory in both rectal and colon cancer to drive the appropriate therapeutic workflow. Important limitations of US, CT, and MR in N-staging can be partially solved by FDG PET/CT. Distant staging is usually managed by CT, with MR and FDG PET/CT which can be used as problem-solving techniques. Follow-up is performed according to the general recommendations of the oncological societies. CLINICAL RELEVANCE STATEMENT: It is essential to summarize each phase of colorectal cancer workup, differentiating the management for colon and rectal cancer supported by the main international guidelines and literature data, with the aim to inform the community on the best practice imaging in colorectal cancer. KEY POINTS: • Colorectal cancer is a prevalent disease that lends itself to imaging at each stage of detection and management. • Various imaging modalities can be used as adjuncts to, or in place of, direct visualization methods of screening and are necessary for evaluating metastatic disease. • Reevaluation of follow-up strategies should be considered depending on patients' individual risk of recurrence.

Evaluation of 18 CT signs in diagnosing cecal volvulus: a multi-reader retrospective study

PURPOSE

To assess the diagnostic performance and reliability of 18 CT signs to diagnose cecal volvulus, a surgical emergency, versus a group of non-volvulus mimickers.

MATERIALS AND METHODS

Four radiologists retrospectively and independently assessed 18 CT signs in 191 patients with cecal volvulus (n = 63) or a non-volvulus control group ((n = 128), including cecal bascule (n = 19), mobile cecum (n = 95), and colonic pseudo-obstruction (n = 14)) at a single institution from 2013 to 2021. Fleiss' kappa coefficient was used to assess inter-reader agreement. For diagnostic performance metrics, we assessed sensitivity, specificity, and positive and negative predictive values. For predictive performance, all 18 signs were included in bivariate and stepwise lasso multivariate logistic regression models to diagnose cecal volvulus. Performance was assessed by ROC curves.

RESULTS

191 patients (mean age: 63 years +/- 15.5 [SD]; 135 women) were included in the study. Nine of the 18 CT signs of cecal volvulus demonstrated good or better (> 0.6) inter-reader agreement. Individual CT signs with sensitivity, specificity, positive and negative predictive values all above 70% for diagnosing cecal volvulus were transition point, bird beak, and X-marks-the-spot. A lasso regression model determined four CT features: transition point, bird beak, coffee bean, and whirl had excellent prediction (AUC = .979) for cecal volvulus if all present.

CONCLUSION

CT signs for cecal volvulus that have high sensitivity and specificity include: transition point, bird beak, and X-marks-the-spot and were reliable in distinguishing non-volvulus mimickers. If the following four features were present: transition point, bird beak, coffee bean, and whirl, there was excellent prediction (AUC = .979) for cecal volvulus.

Bowel obstruction: signs indicating the need for urgent surgery

Bowel obstruction is common in emergency departments. Obstruction is more common in the small bowel than in the large bowel. The most common cause is postsurgical adhesions. Nowadays, bowel obstruction is diagnosed with multidetector computed tomography (MDCT). MDCT studies for suspected bowel obstruction should focus on four points that need to be mentioned in the report: confirming the obstruction, determining whether there is a single transition point or whether the obstruction is found in a closed loop, establishing the cause of the obstruction, and seeking signs of complications. Identifying signs of ischemia is important in the management of the patient because it enables patients at higher risk of poor outcomes after conservation treatment who could benefit from early surgical intervention to avoid greater morbidity and mortality associated with strangulation and ischemia of the obstructed bowel loop.

Impact of gastric and bowel surgery on gastrointestinal drug delivery

General surgical procedures on the gastrointestinal tract are commonly performed worldwide. Surgical resections of the stomach, small intestine, or large intestine can have a significant impact on the anatomy and physiological environment of the gastrointestinal tract. These physiological changes can affect the effectiveness of orally administered formulations and drug absorption and, therefore, should be considered in rational drug formulation design for specific pathological conditions that are commonly associated with surgical intervention. For optimal drug delivery, it is important to understand how different surgical procedures affect the short-term and long-term functionality of the gastrointestinal tract. The significance of the surgical intervention is dependent on factors such as the specific region of resection, the degree of the resection, the adaptive and absorptive capacity of the remaining tissue, and the nature of the underlying disease. This review will focus on the common pathological conditions affecting the gastric and bowel regions that may require surgical intervention and the physiological impact of the surgery on gastrointestinal drug delivery. The pharmaceutical considerations for conventional and novel oral drug delivery approaches that may be impacted by general surgical procedures of the gastrointestinal tract will also be addressed.

Imaging Signs for Determining Surgery Timing of Acute Intestinal Obstruction

We aimed to analyze the computed tomography (CT) imaging signs of bowel wall ischemia in patients with acute intestinal obstruction and construct an imaging prediction model to guide clinical treatment. The CT imaging signs of patients with acute intestinal obstruction diagnosed in our center in recent 6 years were collected for retrospective analysis. The etiology of intestinal obstruction and incidence rate of bowel wall ischemia were recorded, and the specific CT findings of bowel wall ischemia, including mesenteric edema, bowel wall thickening, and fish tooth sign, were analyzed. Among the 302 patients selected, 130 surgically treated patients were eligible for analysis. Bowel wall ischemia in acute intestinal obstruction showed an incidence rate of 14.90%, and the incidence rates of bowel wall ischemia in intra-abdominal hernia, intussusception, incarcerated external abdominal hernia, and volvulus were about 92.30%, 50%, 35.71%, 33.33%, and 12.59%, respectively. The incidence rate of bowel wall ischemia in simple adhesive intestinal obstruction was about 12.59%, and that in malignancy-induced intestinal obstruction was about 6.56%. Univariate analysis revealed 5 factors with statistical significance, including bowel wall thickening, mesenteric edema, bowel wall pneumatosis, ascites, and fish tooth sign. Multivariate logistic regression analysis indicated that fish tooth sign, bowel wall thickening, and mesenteric edema were able to predict bowel wall ischemia, and the corresponding partial regression coefficients were 2.164, 1.129, and 1.173, odds ratios (ORs) were 8.707, 3.093, and 3.232, sensitivity was 0.356, 0.400, and 0.844, and specificity was 0.859, 0.835, and 0.529, respectively. Imaging signs of bowel wall thickening, mesenteric edema, and fish tooth sign are valuable in predicting bowel wall ischemia, among which bowel wall thickening and mesenteric edema have relatively high specificity and fish tooth sign has a relatively high sensitivity. Furthermore, a fish tooth sign has the most favorable predictive value for bowel wall ischemia in acute intestinal obstruction, followed by bowel wall thickening and mesenteric edema.

Predictive factors of high comprehensive complication index in colorectal cancer patients using Enhanced Recovery After Surgery protocol: role as a safety net in early discharge

Purpose

This study was performed to evaluate complications using comprehensive complication index (CCI) in colorectal cancer patients with implementation of the Enhanced Recovery After Surgery (ERAS) protocol, and to investigate the predictive factors associated with high morbidity rates. It can be used as a safety net in determining the timing of discharge.

Methods

A total of 335 consecutive patients who underwent elective colorectal cancer surgery between January 2017 and December 2017 at a single tertiary center were enrolled. Postoperative complications were defined as occurring within 30 days after surgery. The predictive factor analysis for the high CCI group was also performed.

Results

In total, 116 patients experienced postoperative complications. Wound-related complications and postoperative ileus were the most common. The mean CCI for overall colorectal cancer surgery was 9.1 ± 16.7. Patients featuring low CCI (<26.2) were 297 (88.7%) and high CCI were 38 (11.3%). In multivariable analysis, obstructive colorectal cancer (odds ratio, 3.278; 95% confidence interval, 1.217–8.829; P = 0.019) and CRP value on postoperative day (POD) 3–4 (odds ratio, 1.152; 95% confidence interval, 1.036–1.280; P < 0.010) were significant predictors for high CCI.

Conclusion

The clinical usefulness of CCI in colorectal cancer patients with the ERAS protocol was verified, and it can be used for surgical quality control. More cautious care is needed and the timing of discharge should be carefully determined for patients with obstructive colorectal cancer or POD 3–4 CRP of ≥6.47 mg/dL.