Imaging in bariatric surgery: service set-up, post-operative anatomy and complications

Up-to-date review into the evolving world of bariatric interventions: a guide for radiologists

Obesity is a worldwide health concern leading to several chronic health problems and comorbidities. Its treatment requires a multidisciplinary approach where lifestyle changes are fundamental. Additionally, in the past decade, the use of different surgical procedures of various levels of complexity has grown, with the objective of reducing the gastric capacity, creating diversions, or a combination of both. The aim of this article is to review and illustrate the major types of bariatric surgical techniques, their normal post-surgical anatomy, and the possible associated complications, to aid the radiologist in their assessment and timely diagnosis.

Effects of body part thickness on low-contrast detail detection and radiation dose during adult chest radiography

INTRODUCTION

Differences in patient size often provide challenges for radiographers, particularly when choosing the optimum acquisition parameters to obtain radiographs with acceptable image quality (IQ) for diagnosis. This study aimed to assess the effect of body part thickness on IQ in terms of low-contrast detail (LCD) detection and radiation dose when undertaking adult chest radiography (CXR).

METHODS

This investigation made use of a contrast detail (CD) phantom. Polymethyl methacrylate (PMMA) was utilised to approximate varied body part thicknesses (9, 11, 15 and 17 cm) simulating underweight, standard, overweight and obese patients, respectively. Different tube potentials were tested against a fixed 180 cm source to image distance (SID) and automatic exposure control (AEC). IQ was analysed using bespoke software thus providing an image quality figure inverse (IQFinv ) value which represents LCD detectability. Dose area product (DAP) was utilised to represent the radiation dose.

RESULTS

IQFinv values decreased statistically (P = 0.0001) with increasing phantom size across all tube potentials studied. The highest IQFinv values were obtained at 80 kVp for all phantom thicknesses (2.29, 2.02, 1.8 and 1.65, respectively). Radiation dose increased statistically (P = 0.0001) again with increasing phantom thicknesses.

CONCLUSION

Our findings demonstrate that lower tube potentials provide the highest IQFinv scores for various body part thicknesses. This is not consistent with professional practice because radiographers frequently raise the tube potential with increased part thickness. Higher tube potentials did result in radiation dose reductions. Establishing a balance between dose and IQ, which must be acceptable for diagnosis, can prevent the patient from receiving unnecessary additional radiation dose.

Generation of tissues outside the field of view (FOV) of radiation therapy simulation imaging based on machine learning and patient body outline (PBO)

BACKGROUND

It is not unusual to see some parts of tissues are excluded in the field of view of CT simulation images. A typical mitigation is to avoid beams entering the missing body parts at the cost of sub-optimal planning.

METHODS

This study is to solve the problem by developing 3 methods, (1) deep learning (DL) mechanism for missing tissue generation, (2) using patient body outline (PBO) based on surface imaging, and (3) hybrid method combining DL and PBO. The DL model was built upon a Globally and Locally Consistent Image Completion to learn features by Convolutional Neural Networks-based inpainting, based on Generative Adversarial Network. The database used comprised 10,005 CT training slices of 322 lung cancer patients and 166 CT evaluation test slices of 15 patients. CT images were from the publicly available database of the Cancer Imaging Archive. Since existing data were used PBOs were acquired from the CT images. For evaluation, Structural Similarity Index Metric (SSIM), Root Mean Square Error (RMSE) and Peak signal-to-noise ratio (PSNR) were evaluated. For dosimetric validation, dynamic conformal arc plans were made with the ground truth images and images generated by the proposed method. Gamma analysis was conducted at relatively strict criteria of 1%/1 mm (dose difference/distance to agreement) and 2%/2 mm under three dose thresholds of 1%, 10% and 50% of the maximum dose in the plans made on the ground truth image sets.

RESULTS

The average SSIM in generation part only was 0.06 at epoch 100 but reached 0.86 at epoch 1500. Accordingly, the average SSIM in the whole image also improved from 0.86 to 0.97. At epoch 1500, the average values of RMSE and PSNR in the whole image were 7.4 and 30.9, respectively. Gamma analysis showed excellent agreement with the hybrid method (equal to or higher than 96.6% of the mean of pass rates for all scenarios).

CONCLUSIONS

It was first demonstrated that missing tissues in simulation imaging could be generated with high similarity, and dosimetric limitation could be overcome. The benefit of this study can be significantly enlarged when MR-only simulation is considered.

Common, Less Common, and Unexpected Complications after Bariatric Surgery: A Pictorial Essay

Bariatric surgery has demonstrated a higher rate of success than other nonsurgical treatments in selected patients with obesity; however, like all medical procedures, postoperative complications may occur, ranging between 2 and 10% and, although rare, they can be life threatening. Complications may be unspecific (any surgery-related complications) or specific (linked to the specific surgical procedure) and can be distinguished as common, less common, and unexpected. According to the onset, they may be acute, when occurring in the first 30 days after surgery, or chronic, with a presentation after 30 days from the procedure. The aim of this pictorial essay is to review the radiological aspects of surgical techniques usually performed and the possible complications, in order to make radiologists more confident with the postsurgical anatomy and with the normal and abnormal imaging findings.

Imaging after laparoscopic sleeve gastrectomy - literature review with practical recommendations

In the XXI century obesity has become one of the most demanding epidemiological threats worldwide. At the same time, bariatric surgery has established itself as an effective treatment for morbidly obese patients, with laparoscopic sleeve gastrectomy (LSG) emerging as the most popular bariatric procedure. This paper reviews the role of imaging studies of patients after LSG. Computed tomography is widely considered as the method of choice in detection of complications in early postoperative period. The dynamic character of upper gastrointestinal examination allows for the assessment of passage through the gastric remnant. The paper also discusses evaluation of the shape and volume of the gastric remnant assessed by imaging studies.

Role of imaging in assessment and detection of complications after bariatric surgery

Background

Bariatric surgery is performed to control morbid obesity secondary to failed medical approaches. Practical knowledge of post-surgical anatomy allows accurate interpretation of imaging findings related to normal post-surgical anatomy and common post-surgical complications.

The purpose of this study was to highlight the role of imaging in the assessment and detection of complications after bariatric surgery.

Results

This prospective study included 49 patients who had bariatric surgery. Sleeve gastrectomy was the most common bariatric surgery. The leak was the commonest complication (12%). The sensitivity of upper GI series for diagnosis of post-operative complication after bariatric surgery was 70% and specificity 94% while the sensitivity of CT study was 95% and specificity 95%.

Conclusion

CT has a golden role in the diagnosis of post-operative complications. Both post-contrast CT and upper GI series should be used in diagnosing complications following bariatric surgery. US is useful for diagnosis of a superficial problem.

A review of commonly performed bariatric surgeries: Imaging features and its complications

Obesity is a disease that has achieved the level that can be considered an epidemic. According to the National Center for Health Statistics data, the prevalence of obesity has increased from 30.5% in 1999-2000 to 42.4% in 2017-2018. During the same period, severe obesity has increased from 4.7% to 9.2%. With the growing prevalence of obesity, related conditions such as coronary artery disease, diabetes, and strokes have also become more prevalent. In the past few years, the need for bariatric surgeries such as laparoscopic Roux-en-Y gastric bypass, sleeve gastrectomy, and laparoscopic adjustable gastric banding has increased considerably. With an increasing number of bariatric surgeries, multiple postoperative complications have become common. In this review, we have attempted to describe normal postsurgical anatomical findings after bariatric surgeries and pictorial review of a few common postoperative complications.

Lack of benefit of routine abdominal CT-scan before bariatric surgery

BACKGROUND

Scientific societies recommend to seek cancer prior to bariatric surgery. In our tertiary referral center, we aimed to study performance of abdominal CT-scan before bariatric surgery.

PATIENTS AND METHODS

We retrospectively included all patients who underwent bariatric surgery and a pre-operative abdominal CT-scan in our academic center, between January 2015 and December 2018.

RESULTS

We included 521 patients (417 women and 104 men) with a mean age of 48.0±11.5 years. Mean preoperative body mass index was 44.9±7.0kg/m². Among the 392 patients with abnormal CT-scan, mean number of anomalies per patient was of 2.2±1.2. Vast majority of anomalies (91.8%) were non-significant. Only 5 (1%) patients needed treatment prior to bariatric surgery. No factor predictive of abnormal CT-scan was found.

CONCLUSION

Only few patients had severe anomaly on CT-scan before bariatric surgery. Abdominal CT-scan could not be advocated to seek cancer before bariatric surgery.

Value of contrast-enhanced multidetector computed tomography in imaging of symptomatic patients after laparoscopic Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy

Background

To assess the role of contrast-enhanced multidetector computed tomography (MDCT) in the assessment of symptomatic patients following laparoscopic Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy.

Results

We reviewed the studies of 129 cases and found complications in 113 patients: 55 early complications and 48 late complications. All of these complications were diagnosed with intravenous contrast-enhanced MDCT. Statistically significant difference was found between UGIS and MDCT in the diagnosis of many cases.

Conclusion

The rate of complications in bariatric surgery is high and the associated mortality is not negligible. The interpreting radiologists should know the normal postoperative findings and be aware of possible complications.

Optimizing Projectional Radiographic Imaging of the Abdomen of Obese Patients: An e-Delphi Study

PURPOSE

Obesity is increasing in prevalence globally, with increased demands placed on radiology departments to image obese patients to assist with diagnosis and management. The aim of this study was to determine perceived best practice techniques currently used in clinical practice for projectional radiography of the abdomen for obese patients with the aim to help elucidate areas for future research and education needs in this field.

EXPERIMENTAL DESIGN

A two round e-Delphi study was undertaken to establish a consensus within a reference group of expert Australian clinical educator diagnostic radiographers (CEDRs). Initially, a conceptual map of issues regarding imaging obese patients was undertaken by analysing interview transcripts of 12 CEDRs. This informed an online questionnaire design used in Delphi rounds 1 and 2. A consensus threshold was set <75% "agreement/disagreement", with 15 and 14 CEDRs participating in rounds 1 and 2, respectively.

RESULTS

Seven of the 11 statements reach consensus after round 2. Consensus on using a combination of higher peak kilovoltage (kVp) and milliampere-seconds (mAs) to increase radiation exposure increased source-to-image distance and tighter collimation was achieved. There was no consensus regarding patient positioning practices or patient communication strategies. The expert group reported the importance of personal confidence and treating patients as individuals when applying techniques.

CONCLUSION

Diversity of experts' opinions and current practice may be due to the variations in obese patients' size and presentation. Therefore, there is a need for extensive empirical evidence to underpin practice and education resources for radiographers when imaging obese patients.

Is There a Relationship Between Body Mass Index and Fluoroscopy Time During Cervical Interlaminar Epidural Steroid Injections?

Background

The challenge of obtaining medical imaging in individuals with higher body mass index (BMI) is described, but there is minimal data regarding the relationship between BMI and fluoroscopy time during cervical interlaminar epidural steroid injection (CIESI).

Objective

To determine the relationship between BMI and fluoroscopy time during CIESI.

Methods

Retrospective cohort study of patients who underwent fluoroscopically guided CIESI between January 2014 and February 2015 at an academic pain medicine center. Fluoroscopy time data were collected. Comparisons based on analysis of variance were made between patients with normal (<25.0 kg/m 2 ), overweight (25.0-29.9 kg/m 2 ), and obese (≥30.0 kg/m 2 ) BMI.

Results

Of 399 procedure encounters, 366 had documented BMI and fluoroscopy time data and were included for analysis. Mean age (± SD) in this cohort was 53 ± 13 years, including 189 females (52%) and 205 first-time injections. Mean fluoroscopy time for all injections was 18 ± 10 seconds. Separated by categorical BMI class, the mean fluoroscopy time was 18 ± 9 seconds for normal weight patients, 17 ± 10 seconds for overweight patients, and 20 ± 11 seconds for obese patients, respectively. Post hoc analysis showed that fluoroscopy time was significantly longer only in obese compared with overweight patients ( P  = 0.02). Trainee involvement and first-time vs repeat injection did not significantly alter fluoroscopy time ( P  = 0.17 and P  = 0.12, respectively).

Conclusions

The findings of this study indicate that BMI does not appear to have a clinically significant impact on fluoroscopy time during cervical interlaminar epidural steroid injection procedures. Future study is needed to directly quantify radiation exposure in patients and practitioners, as well as the associated health risk.

Role of Routine Abdominal Ultrasound Before Bariatric Surgery: Review of 937 Patients

INTRODUCTION

Routine use of preoperative abdominal ultrasound for patients undergoing bariatric surgery is controversial. Despite that some physicians routinely implement it, others consider it unnecessary and not cost effective because it does not have a clear clinical significance in the preparation of bariatric patients.

AIM OF THE STUDY

To investigate whether routine abdominal ultrasound prior to bariatric surgery affects the surgical plan or not.

PATIENTS AND METHODS

We reviewed medical records of patients with abdominal ultrasound before bariatric surgery in Rashid Hospital between June 2014 and December 2016. Patients were divided into four groups: group 0 included patients with normal abdominal ultrasound, group 1 included abnormalities that did not affect timing or type of procedure, group 2 included findings that did not affect surgical plan but needed postoperative follow-up, and group 3 included abnormalities that had a direct impact on the procedure.

RESULTS

One thousand one hundred twenty files were reviewed. Results were missing in 183 files, thus excluded; remaining 937 files were included. Mean age of patients was 37 ± 12 years, 589 (63%) were females and 348 (37%) were males. Mean BMI was 45.1 ± 9.8 kg/m². Ultrasound was normal in 354 (37.7%) of patients and abnormal in 583 (62.3%).

CONCLUSION

Routine abdominal ultrasound does not seem to have an important part in preoperative preparation of patients before bariatric surgery. Further studies could be helpful in discussing this role and building up clear solid evidence and guidelines that could be approved by international bariatric associations regarding the indication of preoperative abdominal ultrasound before bariatric surgery.

Comparison of Imaging Modalities for Detecting Complications in Bariatric Surgery

PURPOSE

The purpose of this study is to evaluate the results of routine fluoroscopic swallowing study (FSS) imaging 24 h after surgery and computed tomography (CT) on demand based on clinical data, in diagnosing complications after bariatric surgery.

MATERIAL AND METHODS

This retrospective study includes 9386 patients that underwent bariatric surgery. A total of 3241 (34.53%) patients underwent FSS imaging following the surgical procedure, and 106 (1.13%) patients underwent CT.

RESULTS

Sleeve gastrectomy was performed in 8093 patients (75.81%), gastric bypass was performed in 1281 patients (12%), duodenal switch or biliopancreatic diversion was performed in 12 patients (0.11%), and gastric banding was performed in 1289 patients (12.07%), which were excluded from the study as no imaging modality was used in any of these patients. The sensitivity for FSS was 71.43% and the specificity was 99.85%. An analysis of disease prevalence revealed a value of 0.43% with a positive predictive value of 66.67%. The sensitivity for CT was 71.42% and the specificity was 98%. A disease prevalence analysis revealed a value of 6.60% with a positive predictive value of 83.33%. A comparison of the two modalities showed that FSS has higher specificity values (p < 0.02) and a higher accuracy (p < 0.0001) than CT.

CONCLUSION

CT and FSS have a similar sensitivity for diagnosing complications after bariatric surgery. However, the specificity and accuracy of FSS are superior to that of CT. This study was approved by the instructional ethics committee (Helsinki board) and was registered on the National Institutes of Health ( ClinicalTrials.gov ) web site with identifier NCT02813122.

Hyperirritable stomach as a cause of obstructive symptoms after sleeve gastrectomy: clinical and radiographic findings

PURPOSE

To characterize clinical and radiographic features of a hyperirritable stomach after sleeve gastrectomy.

MATERIALS/METHODS

Radiology reports revealed that 10/76 patients (13%) with obstructive symptoms after sleeve gastrectomy had a hyperirritable stomach.

RESULTS

All 10 patients presented with nausea, vomiting, and/or regurgitation. All 10 had emesis on barium studies in the absence of gastric outlet obstruction, gastroparesis, or small bowel obstruction/ileus. Five had extraintestinal causes of nausea/vomiting. Eight had improvement/resolution of symptoms on medical treatment.

CONCLUSION

In 13% of patients with nausea/vomiting after sleeve gastrectomy, barium studies revealed a hyperirritable stomach, which likely is multifactorial and self-limited in most patients.

A new proposed mechanism of action for gastric bypass surgery: Air hypothesis

Roux-en-Y gastric bypass (RYGB) surgery is one of the most effective treatments for obesity and type II diabetes. RYGB was originally believed to work by mechanically restricting caloric intake or causing macronutrient malabsorption. However, such mechanical effects play no role in the remarkable efficacy of gastric bypass. Instead, mounting evidence shows that altered neuroendocrine signaling is responsible for the weight reducing effects of RYGB. The exact mechanism of this surgical response is still a mystery. Here, we propose that RYGB leads to weight loss primarily by inducing a functional shift in the gut microbiome, manifested by a relative expansion of aerobic bacteria numbers in the colon. We point to compelling evidence that gastric bypass changes the function of the microbiome by disrupting intestinal gas homeostasis, causing excessive transit of swallowed air (oxygen) into the colon.

Evaluation of GPU-Based CT Reconstruction for Morbidly Obese Patients

The obese population is increasing in the United States. There have been modest improvements in scanner hardware and image processing to address some specific challenges associated with imaging of the morbidly obese patients. However, most legacy CT systems lack capabilities to provide sufficient delivery of image-based diagnosis in this increasing subset of population. One of the most common problems is the projection data truncation in CT imaging due to the massive girths of obese patients. In the past decade, it was proved that the image can be accurately and stably reconstructed from locally truncated projections if certain prior knowledge is known, and this technique is named interior tomogrpahy. To overcome the time-consuming issue of the iterative algorithms, we apply GPU techniques to speed up the reconstruction process. In this paper, we evaluate the GPU-based CT reconstruction algorithms (one analytic algorithm and one iterative reconstruction algorithm) for obese patients with both simulated and real clinical datasets. While the approximate analytic reconstruction algorithm outperforms the iterative reconstruction (IR) algorithm in terms of computational cost, the IR algorithm outperforms the analytic one in terms of image quality especially when the projection data is suffered from patient motion, which can happen when the obese patients are not able to hold a breath during the scan.

Post Roux-en-Y gastric bypass complications: A comparative study assessing the clinical effectiveness of oesophagogastroduodenoscopy and oral-contrast swallow

INTRODUCTION

Anastomotic strictures at the gastrojejunal anastomosis have been reported to occur in 3-20% of patients following a Roux-en-Y gastric bypass (RYGB). Patients commonly present with dysphagia, vomiting and post-prandial pain. Clearly using the appropriate investigations to diagnose the potential complications have both clinical and economical benefits. The reported study compared whether Oesophagogastroduodenoscopy (OGD) or oral-contrast swallow should be employed in patient presenting with post-operative complications following RYGB.

METHODS

A retrospective study was conducted on 112 patients between 2008 and 2012; at a level 4 bariatric surgery hospital. Patients who had ≥1 OGD to investigate a post-operative complication were included for analysis. Oral-contrast swallow radiology reports performed <28 days prior to an OGD were included for analysis. Patient demographics, OGD, oral-contrast swallow and additional interventions reports were collated from electronic records, pathology and radiology results.

RESULTS

112 patients underwent 1 or more OGD. 75% (n = 67) of patients were diagnosed with a post-operative complication with the most common, 51% (n = 57) being a gastrojejunal anastomotic stricture. 82% (n = 47) of patients presented with dysphagia + - vomiting prior to the diagnosis of gastrojejunal anastomotic strictures. 96% (n = 55) of patients with gastrojejunal anastomotic strictures were successfully treated with balloon dilation. 48% (n = 54) of patients had an oral-contrast swallow as a first line investigation for post-operative symptoms prior to the OGD. 15% (n = 8) of oral-contrast swallow were reported with a significant pathology, with only 1 stricture identified. 70% (n = 38) of oral-contrast swallows reported as normal had a pathology identified at OGD, including 28 strictures.

CONCLUSION

We recommend that an OGD should be performed in patients presenting with symptoms consistent with a stricture following RYGB. The urgency of the OGD will be dictated by clinical correlation. The use of a water-soluble contrast swallow should be reserved for a suspected anastomotic leak.

Multidetector CT imaging of bariatric surgical complications: a pictorial review

The prevalence of obesity is increasing, along with the number of bariatric surgical procedures performed to treat obesity. Laparoscopic sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), and laparoscopic gastric banding (GB) comprise the vast majority of procedures with SG now the dominant procedure in the USA. Although multidetector computed tomography (MDCT) is not always the examination of choice for a particular suspected complication, many of these patients present with non-specific abdominal symptoms and undergo MDCT evaluation as an initial diagnostic test. This pictorial essay will review and discuss the normal post-surgical bariatric appearance on MDCT, and the appearance of common and uncommon complications associated with the common bariatric procedures on MDCT with correlative imaging. SG complications include leak/abscess, hemorrhage, splenic injury, and portomesenteric thrombosis. RYGB complications include leak/abscess, gastrogastric fistula, small bowel obstruction, internal hernia, and intussusception. Although GB is waning in popularity, radiologists continue to see the legacy of these patients and complications include gastric prolapse, band erosion, and port/tubing mechanical failures. Awareness of the characteristic findings of bariatric complications on MDCT is critical, allowing for earlier recognition and prompt intervention.

Cross-sectional imaging, with surgical correlation, of patients presenting with complications after remote bariatric surgery without bowel obstruction

Both restrictive and malabsorptive types of bariatric surgery may be associated with short- and long-term complications. The lack of small bowel obstruction is not necessarily indicative of a normal study, as a variety of non-obstructed complications exist. These include stenosis at the gastrojejunostomy, leaks, abscesses, hemorrhage, internal hernias, and gastric band erosions. Radiologists should be familiar with these complications for early diagnosis and intervention before symptoms become life threatening. An understanding of the intraoperative appearances of these complications may improve imaging descriptions and add value to radiological consults for surgeons. This review provides surgical correlations to the imaging features of post-bariatric complications without obstruction of the bowel.

Relationship between gastric pouch and weight loss after laparoscopic sleeve gastrectomy

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) is considered safe and effective even as conversion procedure after primary bariatric operations. The correlation between gastric pouch volumes and patients weight loss remains unclear.

METHODS

To assess a correlation between the gastric remnant size and the weight loss, we reviewed 49 consecutive barium swallow UGS performed at our institute from August 2012 through May 2014 in LSG patients with symptoms and/or unsatisfactory weight loss. The anteroposterior (AP), laterolateral (LL) and vertical (CC) diameters of the gastric pouch were measured to calculate the volume by the formula of the ellipsoid (AP × LL × CC × 0.5). Patients were divided in two groups: group 1 without gastric pouch (n = 36) and group 2 with gastric pouch (n = 13). Correlation between pouch volume and weight loss data was calculated with t Student's and Fisher tests to compare the percent excess body mass index (BMI) and percent excess body mass loss (EBL) between two groups, and P < 0.05 was considered statistically significant.

RESULTS

The mean percent EBL was 26.54 ± 11.02 and 27.12 ± 12.35 kg/m(2) in groups with and without pouch, respectively. The mean volume of the pouch after LSG was 17.13 ± 21.56 mm(3). Pouch volume, when present, was not significantly correlated to weight loss (P = 0.88 95% CI, CL 19.88-33.20 group 2; CL 22.94-31.30 group 1).

CONCLUSIONS

No statistical correlation was found between the volume of the gastric pouch and weight loss (percent EBL) after LSG in symptomatic or with unsatisfactory weight loss patients.

Imaging of complications of common bariatric surgical procedures

Several techniques for the surgical management of obesity are available to bariatric surgeons. These interventions are performed more frequently with worsening of the obesity epidemic. Radiologists should be familiar with the surgical techniques, normal postoperative appearances, and potential complications for which imaging may be employed to establish a diagnosis to optimize patient care.

Imaging of bariatric surgery: normal anatomy and postoperative complications

Obesity is a disease that has reached epidemic proportions in the United States and around the world. During the past 2 decades, bariatric surgery has become an increasingly popular form of treatment for morbid obesity. The most common bariatric procedures performed include laparoscopic Roux-en-Y gastric bypass, laparoscopic adjustable gastric banding, and laparoscopic sleeve gastrectomy. Fluoroscopic upper gastrointestinal examinations and abdominal computed tomography (CT) are the major imaging tests used to evaluate patients after these various forms of bariatric surgery. The purpose of this article is to present the surgical anatomy and normal imaging findings and postoperative complications for these bariatric procedures at fluoroscopic examinations and CT. Complications after Roux-en-Y gastric bypass include anastomotic leaks and strictures, marginal ulcers, jejunal ischemia, small bowel obstruction, internal hernias, intussusception, and recurrent weight gain. Complications after laparoscopic adjustable gastric banding include stomal stenosis, malpositioned bands, pouch dilation, band slippage, perforation, gastric volvulus, intraluminal band erosion, and port- and band-related problems. Finally, complications after sleeve gastrectomy include postoperative leaks and strictures, gastric dilation, and gastroesophageal reflux. The imaging features of these various complications of bariatric surgery are discussed and illustrated.

Imaging obese patients: problems and solutions

Obesity is an epidemic in the United States and Western World with an associated increasing impact on radiology departments. The increased prevalence of obesity in conjunction with the growing use and success of bariatric surgery results in an influx of obese patients into the health system in need of hospital services and care. Imaging services in particular are in demand in this patient population. Obese patients place special needs upon facilities and imaging equipment and also create technical challenges. This manuscript will address problems and potential solutions for imaging obese patients, specifically with regards to the modalities of radiography, fluoroscopy, computed tomography, and magnetic resonance imaging.

Complications of Roux-en-Y gastric bypass and sleeve gastrectomy

Roux-en-Y gastric bypass and sleeve gastrectomy are two of the most common bariatric procedures performed in 2011. Although the complication rates associated with these procedures are low, the consequences of these complications are significant and can be associated with high morbidity and mortality. Timely diagnosis and proper management of these complications are extremely important. The most commonly used radiologic studies in bariatric surgery are the upper GI contrast study and the CT scan, which are used to rule out leak, obstruction, perforation, anastomotic stricture, or pouch dilatation. As with all imaging studies, a negative result should not override strong clinical suspicion of a complication.

C-reactive protein 2 days after laparoscopic gastric bypass surgery reliably indicates leaks and moderately predicts morbidity

BACKGROUND

The aim of the present study was to evaluate whether serum C-reactive protein (CRP) is a useful predictor of early post-operative complications, particularly of intestinal leaks after laparoscopic Roux-en-Y gastric bypass (LRYGB) surgery.

METHODS

The present study was a retrospective analysis of a prospectively maintained database with 809 patients who underwent LRYGB from 2002 until 2011. For 410 of these patients, at least one CRP measurement within the first seven post-operative days was available. The diagnostic value was determined by the area under the curve (AUC) of the receiver operating characteristic (ROC) curve.

RESULTS

Forty-nine of 410 patients (12.0 %; 95 % confidence intervals [95 % CI], 9.2-15.5 %) developed surgery-related complications. Leaks occurred in 17 patients (4.1 %; 95 % CI, 2.6-6.5 %) at a median of 5 days after surgery. CRP levels 2 days after surgery showed the highest diagnostic value for post-operative complications (AUC, 0.74; 95 % CI, 0.60-0.89). Sensitivity was 0.53 (95 % CI, 0.31-0.74) and specificity was 0.91 (95 % CI, 0.79-0.96) on day 2 (cutoff level, 229 mg/l). The sensitivity for intestinal leaks was 1.00 (95 % CI, 0.51-1.00).

CONCLUSION

CRP on post-operative day 2 is a valuable predictor of post-operative complications, in particular intestinal leaks. Radiological imaging studies for intestinal leaks could be restricted to patients with CRP values exceeding 229 mg/l.

[Bariatric surgery and associated complications: radiological imaging]

Obesity is an increasing problem faced by the healthcare system. In managing obesity, bariatric surgery is becoming more important with evidence showing a reduction in long-term morbidity and mortality. There are special challenges faced by the radiology department in providing an imaging service for this population of patients, from technical requirements through to the interpretation of post-surgical images. This article provides an overview of the most frequently performed procedures, normal postoperative imaging findings and the appearance of common complications.