[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.

Complications after abdominal surgery

Complications after abdominal surgery are often seen in emergency departments. Many postoperative complications (e.g., infections, abscesses, hematomas, and active bleeding) are common to all types of surgery; others are specific to different types of surgery. Computed tomography (CT) is the technique normally used to diagnose postoperative complications. This article reviews the changes that occur after some of the most common abdominal interventions that can be mistaken for pathological processes, the findings that can be considered normal after surgical intervention, and the most common early complications. It also describes the optimal protocols for CT studies depending on the different types of complications that are suspected.

Post-Surgical Imaging Assessment in Rectal Cancer: Normal Findings and Complications

Rectal cancer (RC) is one of the deadliest malignancies worldwide. Surgery is the most common treatment for RC, performed in 63.2% of patients. The type of surgical approach chosen aims to achieve maximum residual function with the lowest risk of recurrence. The selection is made by a multidisciplinary team that assesses the characteristics of the patient and the tumor. Total mesorectal excision (TME), including both low anterior resection (LAR) and abdominoperineal resection (APR), is still the standard of care for RC. Radical surgery is burdened by a 31% rate of major complications (Clavien-Dindo grade 3-4), such as anastomotic leaks and a risk of a permanent stoma. In recent years, less-invasive techniques, such as local excision, have been tested. These additional procedures could mitigate the morbidity of rectal resection, while providing acceptable oncologic results. The "watch and wait" approach is not a globally accepted model of care but encouraging results on selected groups of patients make it a promising strategy. In this plethora of treatments, the radiologist is called upon to distinguish a physiological from a pathological postoperative finding. The aim of this narrative review is to identify the main post-surgical complications and the most effective imaging techniques.

The role of rectal endoscopic ultrasonography plus fine needle aspirartion and fine needle biopsy in pelvic masses

BACKGROUND AND AIM

The diagnostic role of endoscopic ultrasound (EUS) guided fine needle aspiration (FNA) and fine needle biopsy (FNB) of pelvic masses has not been well established. We aimed to evaluate the diagnostic accuracy of EUS plus FNA/FNB in suspected local recurrence of pelvic masses.

MATERIALS AND METHODS

All consecutive patients with a history of lower gastrointestinal and pelvic mass undergone EUS-FNA/FNB were included in the study.

RESULTS

In total 34 patients who underwent EUS-guided FNA or FNB of a perirectal mass were enrolled. The sampled lesion was a mass in 22 patients (64.7%) and a lymph node in 10 patients (29.4%). The univariate logistic regression analysis for diagnostic accuracy showed lesion size as a significant predictor of diagnostic accuracy [odds ratio (OR), 1.61; 1.08-2.27; P  = 0.02]. Diagnostic sensitivity was 100% (71.5-100%) with EUS-FNB and 75% (34.9-96.8%) with EUS-FNA ( P  = 0.12); specificity was 100% in both groups ( P  = 1.0). Sample adequacy was 94.1% in the whole cohort, with 20/20 adequacy rate (100%) in the EUS-FNB group and 12/14 (85.7%) in the EUS-FNA group ( P  = 0.28).

CONCLUSION

This is the first study demonstrating the diagnostic yield of EUS plus FNA/FNB in patients with pelvic masses comparing the two needles. Our results highlight the relevance of this technique, especially in undefined masses during oncological follow-up.

A novel dual balloon rectal catheter for use in the postoperative assessment of low rectal anastomoses following low anterior resection

Following low anterior resection (LAR) of the colon, an image-guided assessment of the anastomosis for leak is typically performed using an enema via a rectal catheter, whether by CT or fluoroscopy. However, there is potential for poor assessment due to inappropriate catheter positioning as well as potential risk that the anastomosis becomes compromised by the balloon inflation. This article discusses the adaptation of a novel double-balloon catheter (originally designed by a member of our institution for use in pediatric intussusception reduction) for assessment of low rectal anastomoses. The goal of this technical note is to demonstrate our experience with this catheter, primarily through example cases, and explain its potential for optimizing colon distension, minimizing improper catheter placement, and potentially reducing the risk of iatrogenic anastomosis disruption.

Anal Atresia in a Patient Who Had Undergone Hartmann Procedure

Patient: Female, 84-year-old

Final Diagnosis: Anal atresia

Symptoms: Incomplete evacuation

Medication:—

Clinical Procedure: Surgery

Specialty: Surgery

Postoperative complications of colorectal cancer

Colorectal cancer is the third most common cancer, and surgery is the most common treatment. Several surgical options are available, but each is associated with a range of potential complications. The timely and efficient identification of these complications is vital for effective clinical management of these patients in order to minimise their morbidity and mortality. This review aims to describe the range of commonly performed surgical treatments for colorectal surgery. In addition, frequent post-surgical complications are explored with investigative options explained and illustrated.

Imaging of Abdominal Postoperative Complications

We present a case-based review of abdominal postoperative complications, organized by organ system affected, including wound/superficial, hepatobiliary, pancreatic, gastrointestinal, genitourinary, and vascular complications. Both general complications and specific considerations for certain types of operations are described, as well as potential pitfalls that can be confused with complications. Representative cases are shown using all relevant imaging modalities, including CT, fluoroscopy, ultrasound, MRI, and nuclear medicine. Management options are also described, highlighting those that require radiologist input or intervention.

Safety and efficacy of adding intravenous N-acetylcysteine to parenteral L-alanyl-L-glutamine in hospitalized patients undergoing surgery of the colon: a randomized controlled trial

BACKGROUND

Colon surgery can cause systemic inflammatory response syndrome (SIRS). There is a recent trend towards the use of antioxidant agents in the prevention or alleviation of the severity of postoperative SIRS, but its use is controversial as studies have shown conflicting results.

OBJECTIVES

Investigate the efficacy and tolerability of perioperative intravenous administration of N-acetylcysteine (NAC) as an antioxidant and anti-inflammatory agent in patients undergoing colon surgery.

DESIGN

Randomized, double-blinded, and controlled clinical trial.

SETTING

Surgical critical care unit in Egypt.

PATIENTS AND METHODS

Sixty patients who required admission to the ICU following colon surgery were enrolled in the study between July 2015 and October 2016. Eligibility included the need for parenteral nutrition for at least 5 days due to failure of or contraindication to enteral nutrition. Patients were randomly allocated using a computer-generated list to a loading dose of NAC followed by continuous infusion started one hour prior to induction, and continued over 48 hours, or to the control group, who received the same volume of dextrose 5%. Allocation was concealed using opaque, sealed envelopes under pharmacy control. The researcher, the anesthesiologist, the surgeon, and patients were blinded to the treatment allocation.

MAIN OUTCOME MEASURES

Clinical and laboratory evaluation for manifestations of SIRS, serum levels of tumor necrosis factor alpha and malondialdehyde, and occurrence of side effects in the study group.

SAMPLE SIZE

60 patients with mean (SD) ages of 56 (15.1) years in the study group (n=30) and 57.7 (12.3) years in the control group (n=30).

RESULTS

There was a significant difference in the mean serum level of ALT (22.6 (9.9) U/L in the study group vs. 31.1 (17.8) U/L in the control group, P=.028) after treatment with NAC, but differences between the groups in the serum level of tumor necrosis factor alpha and malondialdehyde after treatment were not significant. Serum levels of malondialdehyde increased in both groups after treatment P<.001. There was no statistically significant difference from baseline or between the groups after treatment in other clinical data and laboratory parameters following NAC administration, and only 6.6% of the patients in the study group experienced mild side effects.

CONCLUSIONS

Preoperative administration of NAC is safe, but its efficacy as an antioxidant and anti-inflammatory agent was not statistically significant and requires further investigation in a larger sample.

LIMITATIONS

Single-center study, small sample size, and short duration of NAC administration.

CLINICAL TRIALS REGISTRY

NCT03589495.

CONFLICT OF INTEREST

None.

Urgent Multidetector Computed Tomography in Colon Cancer: Postsurgical Changes and Early Complications

Complications after surgery for colorectal cancer are common in emergency departments. Multidetector computed tomography plays a fundamental role in the follow-up of patients after surgery, because it enables the detection of relapse and complications. Radiologists need to be familiar with different surgical techniques and the normal postsurgical changes so that we can differentiate them from potential complications and relapse. This article reviews the multidetector computed tomography findings that can be considered normal after surgical intervention for colorectal cancer as well as the most common early complications seen in postsurgical colorectal cancer patients presenting at emergency departments.

A closer look at the stoma: multimodal imaging of patients with ileostomies and colostomies

Nowadays, large numbers of ileostomies and colostomies are created during surgical management of a variety of intestinal disorders. Depending on indication, surgical technique and emergency versus elective conditions, stomas may be either temporary or permanent. As a result, patients with ileostomies and colostomies are commonly encountered in Radiology departments, particularly during perioperative hospitalisation following stoma creation or before recanalisation, and when needing CT or MRI studies for follow-up of operated tumours or chronic inflammatory bowel diseases. However, the stoma site is commonly overlooked on cross-sectional imaging.Aiming to improve radiologists' familiarity with stoma-related issues, this pictorial essay concisely reviews indications and surgical techniques for ileostomies and colostomies, and presents state-of-the art multimodal imaging in patients living with a stoma, including water-soluble contrast stomal enema (WSC-SE), CT and MRI techniques, interpretation and expected findings. Afterwards, the clinical features and imaging appearances of early and late stoma-related complications are illustrated with imaging examples, including diversion colitis.When interpreting cross-sectional imaging studies, focused attention to the stoma site and awareness of expected appearances and of possible complications are required to avoid missing significant changes requiring clinical attention. Additionally, dedicated imaging techniques such as WSC-SE and combined CT plus WSC-SE may be helpful to provide surgeons the appropriate clinical information required to direct management.

Colostomy on CT and fluoroscopy: What the radiologist needs to know

Colostomies are commonly created in conjunction with colorectal surgery performed for both malignant and benign indications. Familiarity with the different types of colostomies and their normal imaging appearance will improve radiologic detection and characterization of colostomy complications. The radiologist plays a large role in assessment of colostomy patients either via fluoroscopic technique or multidetector computed tomography (CT) in order to help identify ostomy complications or to aid the surgeon prior to colostomy reversal. In this article, we will review: (1) the types of colostomies and indications for their creation; (2) the proper radiographic technique of ostomy evaluation; and (3) the potential complications of colostomies and their imaging manifestations.

CT findings after pelvic exenteration: review of normal appearances and most common complications

The aim of this review is to illustrate normal computed tomography (CT) findings and the most common complications in patients who underwent pelvic exenteration (PE) for advanced, persistent or recurrent gynecological cancers. We review the various surgical techniques used in PE, discuss optimal CT protocols for postsurgical evaluation and describe cross-sectional imaging appearances of normal postoperative anatomic changes as well as early and late complications. The interpretation of abdominopelvic CT imaging after PE is very challenging due to remarkable modifications of normal anatomy. After this radical pelvic surgery, the familiarity with expected CT appearances is crucial for diagnosis and appropriate management of potentially life-threatening complications in patients who underwent PE.

Role of MRI and added value of diffusion-weighted and gadolinium-enhanced MRI for the diagnosis of local recurrence from rectal cancer

PURPOSE

To evaluate whether the addition of gadolinium-enhanced MRI and diffusion-weighted imaging (DWI) improves T2 sequence performance for the diagnosis of local recurrence (LR) from rectal cancer and to assess which approach is better at formulating this diagnosis among readers with different experience.

METHODS

Forty-three patients with suspected LR underwent pelvic MRI with T2 weighted (T2) sequences, gadolinium fat-suppressed T1 weighted sequences (post-contrast T1), and DWI sequences. Three readers (expert: G, intermediate: E, resident: V) scored the likelihood of LR on T2, T2 + post-contrast T1, T2 + DWI, and T2 + post-contrast T1 + DWI.

RESULTS

In total, 18/43 patients had LR; on T2 images, the expert reader achieved an area under the ROC curve (AUC) of 0.916, sensitivity of 88.9%, and specificity of 76%; the intermediate reader achieved values of 0.890, 88.9%, and 48%, respectively, and the resident achieved values of 0.852, 88.9%, and 48%, respectively. DWI significantly improved the AUC value for the expert radiologist by up to 0.999 (p = 0.04), while post-contrast T1 significantly improved the AUC for the resident by up to 0.950 (p = 0.04). For the intermediate reader, both the T2 + DWI AUC and T2 + post-contrast T1 AUC were better than the T2 AUC (0.976 and 0.980, respectively), but with no statistically significant difference. No statistically significant difference was achieved by any of the three readers by comparing either the T2 + DWI AUCs to the T2 + post-contrast T1 AUCs or the AUCs of the two pairs of sequences to those of the combined three sequences. Furthermore, using the T2 sequences alone, all of the readers achieved a fair number of "equivocal" cases: they decreased with the addition of either DWI or post-contrast T1 sequences and, for the two less experienced readers, they decreased even more with the three combined sequences.

CONCLUSIONS

Both DWI and T1 post-contrast MRI increased diagnostic performance for LR diagnosis compared to T2; however, no significant difference was observed by comparing the two different pairs of sequences with the three combined sequences.

Comparison of the diagnostic efficiency for local recurrence of rectal cancer using CT, MRI, PET and PET-CT: A systematic review protocol

BACKGROUND

The risk of local recurrence (LR) continues to threat patients with rectal cancer after surgery or chemoradiotherapy. The main reason is that there is frequently extensive scarring and reactive changes after radiotherapy and resection. Thus, the diagnosis of LR can be challenging. There are different imaging modalities that have been used in the follow-up of rectal cancer, including computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and positron emission tomography-computed tomography (PET-CT) in clinical practice.

METHODS

We will systematically search PubMed, EMBASE, the Cochrane Library, and Chinese Biomedical Literature Database for diagnostic trials using CT, MRI, PET, and PET-CT to detect LR of rectal cancer in April, 2018. Two review authors will independently screen titles and abstracts for relevance, assess full texts for inclusion, and carry out data extraction and methodological quality assessment using the QUADAS-2 tool. We will use bivariate meta-analysis to estimate summary sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of CT, MRI, PET, and PET-CT, as well as different sequences of MRI. For each index test, estimates of sensitivity and specificity from each study will be plotted in summary receive operating curve space and forest plots will be constructed for visual examination of variation in test accuracy. We will perform meta-analyses using the hierarchical summary receiver-operating characteristic model to produce summary estimates of sensitivity and specificity. Then, head-to-head and indirect comparison meta-analyses will be carried out.

DISCUSSION

This review will help determine the diagnostic accuracy of CT, MRI, PET, and PET-CT for the diagnosis of patients with LR of rectal cancer.

ETHICS AND DISSEMINATION

Ethics approval and patient consent are not required, as this study is a systematic review.

PROSPERO REGISTRATION NUMBER

CRD42018104918.

Imaging of the Postoperative Colon

Recognition of postoperative complications is important for the immediate diagnosis and treatment needed for appropriate patient care. Identification of postoperative complications from colon surgery requires not only knowledge of the type of procedure, but also the expected normal postoperative appearance. The purpose of this article is to discuss and review the expected anatomic changes after colorectal surgery, and the appearance of the most common postoperative complications.

Imaging the operated colon using water-enema multidetector CT, with emphasis on surgical anastomoses

Water-enema multidetector CT (WE-MDCT) provides a detailed multiplanar visualisation of mural, intra- and extraluminal abnormalities of the large bowel, relying on preliminary bowel cleansing, retrograde luminal distension, pharmacological hypotonisation and intravenous contrast enhancement. In patients with a history of colorectal surgery for either carcinoma or Crohn's disease (CD), WE-MDCT may also be performed via a colostomy, which allows depicting the anatomy and position of the residual large bowel and evaluates the calibre, length, mural and extraluminal features of luminal strictures. Therefore, WE-MDCT may prove useful as a complementary technique after incomplete or inconclusive colonoscopy to assess features and suspected abnormalities of the surgical anastomosis, particularly when endoscopic or surgical interventions are being planned. This pictorial essay presents the WE-MDCT technique and pitfalls, the expected appearances after different colic surgeries and the imaging features of benign anastomotic disorders (fibrotic stricture, kinking, inflammatory ulcer) and of locally recurrent tumours and CD.

TEACHING POINTS

• Water-enema multidetector CT (WE-MDCT) effectively visualises the operated colon • Complementary to endoscopy, WE-MDCT may helpfully depict abnormalities of surgical anastomoses • WE-MDCT allows assessment of strictures' features and abnormalities of the upstream bowel • Technical pitfalls, normal postsurgical findings and benign anastomotic disorders are presented • WE-MDCT allows detecting relapsing Crohn's disease, recurrent and metachronous tumours.

PRE- AND POSTOPERATIVE IMAGING METHODS IN COLORECTAL CANCER

INTRODUCTION

Among the screening tests for colorectal cancer, colonoscopy is currently considered the most sensitive and specific technique. However, computed tomography colonography (CTC), magnetic resonance imaging (MRI), and transrectal ultrasonography have gained significant ground in the clinical practice of pre-treatment, screening and, more recently, post-treatment and surgical evaluation.

OBJECTIVE

To demonstrate the high accuracy of CT and MRI for pre and postoperative colorectal cancer staging.

METHODS

Search and analysis of articles in Pubmed, Scielo, Capes Periodicals and American College of Radiology with headings "colorectal cancer" and "colonography". Weew selected 30 articles that contained radiological descriptions, management or statistical data related to this type of neoplasia. The criteria for radiological diagnosis were the American College of Radiology.

RESULTS

The great majority of patients with this subgroup of neoplasia is submitted to surgical procedures with the objective of cure or relief, except those with clinical contraindication. CTC colonography is not the most commonly used technique for screening; however, it is widely used for treatment planning, assessment of the abdomen for local complications or presence of metastasis, and post-surgical evaluation. MRI colonography is an alternative diagnostic method to CT, recommended by the American Society of Gastrointestinal Endoscopy. Although there are still no major studies on the use of MRI for screening, the high resolution examination has now shown good results for the American Joint Committee on Cancer TNM classification.

CONCLUSION

MRI and CT represent the best means for colorectal neoplasm staging. The use of these methods as screening tools becomes beneficial to decrease complications and discomfort related to colonoscopy.

Clinical Etiology of Hypermetabolic Pelvic Lesions in Postoperative Positron Emission Tomography/Computed Tomography for Patients With Rectal and Sigmoid Cancer

Purpose

The purpose of this study was to present various clinical etiologies of hypermetabolic pelvic lesions on postoperative positron emission tomography/computed tomography (PET/CT) images for patients with rectal and sigmoid cancer.

Methods

Postoperative PET/CT images for patients with rectal and sigmoid cancer were retrospectively reviewed to identify hypermetabolic pelvic lesions. Positive findings were detected in 70 PET/CT images from 45 patients; 2 patients who were lost to follow-up were excluded. All PET findings were analyzed in comparison with contrast-enhanced CT.

Results

A total of 43 patients were classified into 2 groups: patients with a malignancy including local recurrence (n = 30) and patients with other benign lesions (n = 13). Malignant lesions such as a local recurrent tumor, peritoneal carcinomatosis, and incidental uterine malignancy, as well as various benign lesions such as an anastomotic sinus, fistula, abscess, reactive lymph node, and normal ovary, were observed.

Conclusion

PET/CT performed during postoperative surveillance of rectal and sigmoid colon cancer showed increased fluorodeoxyglucose uptake not only in local recurrence, but also in benign pelvic etiologies. Therefore, physicians need to be cautious about the broad clinical spectrum of hypermetabolic pelvic lesions when interpreting images.

Nontraumatic large bowel perforation: spectrum of etiologies and CT findings

Large bowel perforation is an abdominal emergency that results from a wide range of etiologies. Computed tomography is the most reliable modality in detecting the site of large bowel perforation. The diagnosis is made by identifying direct CT findings such as extraluminal gas or contrast and discontinuity along the bowel wall. Indirect CT findings can help support the diagnosis, and include bowel wall thickening, pericolic fat stranding, abnormal bowel wall enhancement, abscess, and a feculent collection adjacent to the bowel. Common etiologies that cause large bowel perforation are colon cancer, foreign body aspiration, stercoral colitis, diverticulitis, ischemia, inflammatory and infectious colitides, and various iatrogenic causes. Recognizing a large bowel perforation on CT can be difficult at times, and there are various entities that may be misinterpreted as a colonic perforation. The purpose of this article is to outline the MDCT technique used for evaluation of suspected colorectal perforation, discuss relevant imaging findings, review common etiologies, and point out potential pitfalls in making the diagnosis of large bowel perforation.

Imaging of acute anorectal conditions with CT and MRI

Anorectal disorders are a common cause of presentation to the emergency department (ED). While the most frequently encountered anorectal conditions, such as hemorrhoids and anal fissures, are relatively benign and do not require imaging for diagnosis or management, there are multiple potentially life threatening anorectal conditions for which imaging is an important component of evaluation, diagnosis, and management. Although computed tomography (CT) is the most commonly used imaging modality for evaluation of anorectal pathology in the ED, magnetic resonance imaging (MRI) has an increasingly important role in the detection, characterization and management of specific anorectal conditions. This pictorial essay will review the imaging anatomy of the anorectum, summarize imaging protocols, and discuss the clinical presentation, imaging appearance, and differential diagnosis of anorectal conditions that may present to the emergency department, including infectious, inflammatory, malignant and vascular conditions.

Post-operative colon and urinary diversions: surgical techniques, anatomy, and imaging findings

This article discusses the commonly encountered operative procedures of the colon and urinary diversions and provides a comprehensive review of indications, contraindications, surgical techniques with emphasis on normal and abnormal multimodality imaging findings.

Characteristics of 18F-fluorodeoxyglucose uptake in anastomotic sinus and fistula following rectal cancer surgery

PURPOSE

To assess the characteristics of 18F-fluorodeoxyglucose (FDG) uptake in persisting anastomotic sinus and fistula following rectal cancer surgery.

METHODS

Eight patients with anastomotic sinus and fistula were retrospectively studied.

RESULTS

A total of 13 anastomotic sinuses (n=11) and fistulas (n=2) were observed. Sixteen FDG-positron emission tomography/computed tomography studies for 13 lesions performed and 26 uptake patterns were evaluated. Twenty-one lesions were found to have diffuse increased uptake, whereas four lesions had focal uptake. There was only one lesion without FDG uptake.

CONCLUSIONS

Increased FDG uptake is frequently observed in anastomotic sinus and fistula, which should be known to avoid making wrong diagnosis.

Review of Commonly Used Serum Tumor Markers and Their Relevance for Image Interpretation

Serum tumor markers are firmly entrenched as one of the primary tools in an oncologist's armamentarium. They can be implemented in a broad range of applications from diagnostic assistance, assessing prognosis, or guiding therapeutic decisions. However, tumor markers also have limitations, which significantly impact how they should be used. Radiologists should be familiar with the following most prevalent tumor markers, which will all be discussed here: prostate-specific antigen (prostate), carcinoembryonic antigen (colon), α-fetoprotein (hepatocellular and testicular), carbohydrate antigen 19.9 (pancreas), cancer antigen 125 (ovarian), human chorionic gonadotropin/lactic dehydrogenase (testicular), and chromogranin A (neuroendocrine). This knowledge should avoid needless intervention, enhance image interpretation, and ultimately provide optimal patient care.

Advanced rectal cancer in a long-term Hartmann's pouch: a forgotten organ revisited

Hartmann's procedure is widely performed as a first-stage operation in cases of left colon emergencies when a one stage management is judged to be unsafe. Forty per cent of patients with Hartmann's procedure never get their stoma reversed, ending with a permanent stoma. The distal excluded Hartmann's pouch is usually forgotten compared to the proximal functioning colon. A 70-year-old man with Hartmann's procedure carried out previously for complicated diverticular disease presented with bleeding per rectum. Invasive adenocarcinoma was confirmed on histology. Subsequent staging revealed a locally advanced rectal cancer. The tumour progressed despite a course of neoadjuvant chemoradiation. The general condition of the patient deteriorated with development of renal failure. The patient died a few weeks later. By reporting this case, we are revisiting the long forgotten Hartmann's pouch to highlight the potential pathologies in the distal stump and to emphasise that a distal stump should not be forgotten even in asymptomatic patients.

Imaging the postoperative patient: long-term complications of gastrointestinal surgery

OBJECTIVES

The objectives of this review are (1) to become acquainted with the long-term complications of surgery of the gastrointestinal tract, and (2) to appreciate the appropriate use of imaging in the assessment of long-term complications.

BACKGROUND

Gastrointestinal tract surgery comprises a group of procedures performed for a variety of both benign and malignant diseases. In the late postoperative setting, adhesions and internal hernias are the most important complications. and they can be further complicated by volvulus and ischemia. At present, computed tomography (CT) is the workhorse for evaluating late postoperative complications. Accurate imaging assessment of patients is essential for adequate treatment planning.

IMAGING FINDINGS OR PROCEDURE DETAILS

In this pictorial essay we will review the most frequent long-term complications after gastrointestinal surgery, including adhesions, afferent loop syndrome, closed-loop obstruction, strangulated obstruction, internal hernias, external hernias, anastomotic strictures and disease recurrence. Examples will be depicted using iconography from the authors' imaging department.

CONCLUSIONS

Knowledge of the most frequent complications after gastrointestinal surgery in the late postoperative period is of paramount importance for every radiologist, so that potentially life-threatening situations can be promptly diagnosed and adequate therapy can be planned.

TEACHING POINTS

• Long-term postoperative complications of gastrointestinal tract surgery can be divided into procedure-related and disease-related categories. • The most common procedure-related complications are internal hernias and adhesions. • The most frequent disease-related complications are mainly associated with neoplastic or inflammatory recurrence. • Computed tomography is the most useful examination when such complications are suspected.

The role of CT-guided percutaneous drainage of loculated air collections: an institutional experience

OBJECTIVE

The purpose of this study is to describe our experience with the role of CT-guided percutaneous drainage of loculated intra-abdominal collections consisting entirely of gas.

MATERIALS AND METHODS

An IRB-approved retrospective study analyzing patients with air-only intra-abdominal collections over an 8-year period was undertaken. Seven patients referred for percutaneous drainage were included. Size of collections, subsequent development of fluid, and microbiological yield were determined. Clinical outcome was also analyzed.

RESULTS

Out of 2835 patients referred for percutaneous drainage between 2004 and 2012, seven patients (5M, 2F; average age 63, range 54-85) met criteria for inclusion with CT showing air-only collections. Percutaneous drain placement (five 8 Fr, one 10 Fr, and one 12 Fr) using Seldinger technique was performed. Four patients (57%) had recently undergone surgery (2 Whipple, 1 colectomy, 1 hepatic resection) while two (29%) had a remote surgery (1 abdominoperineal resection, 1 sigmoidectomy). Despite the lack of detectable fluid on the original CT, 6 patients (86%) had air and fluid aspirated at drainage, 5 (83%) of the aspirates developed positive microbacterial cultures. Four patients (57%) presented with fever at the time of the initial scan, all of whom had positive cultures from aspirated fluid. Four patients (57%) had leukocytosis, all of whom had positive cultures from aspirated fluid.

CONCLUSIONS

Although relatively rare in occurrence, patients with air-only intra-abdominal collections with signs of infection should be considered for percutaneous management similar to that of conventional infected fluid collections. Although fluid is not visible on CT, these collections can produce fluid that contains organisms.