Quantification of fluorescence angiography for visceral perfusion assessment: measuring agreement between two software algorithms.

BACKGROUND: Indocyanine green fluorescence angiography (ICG-FA) may reduce perfusion-related complications of gastrointestinal anastomosis. Software implementations for quantifying ICG-FA are emerging to overcome a subjective interpretation of the technology. Comparison between quantification algorithms is needed to judge its external validity. This study aimed to measure the agreement for visceral perfusion assessment between two independently developed quantification software implementations. METHODS: This retrospective cohort analysis included standardized ICG-FA video recordings of patients who underwent esophagectomy with gastric conduit reconstruction between August 2020 until February 2022. Recordings were analyzed by two quantification software implementations: AMS and CPH. The quantitative parameter used to measure visceral perfusion was the normalized maximum slope derived from fluorescence time curves. The agreement between AMS and CPH was evaluated in a Bland-Altman analysis. The relation between the intraoperative measurement of perfusion and the incidence of anastomotic leakage was determined for both software implementations. RESULTS: Seventy pre-anastomosis ICG-FA recordings were included in the study. The Bland-Altman analysis indicated a mean relative difference of + 58.2% in the measurement of the normalized maximum slope when comparing the AMS software to CPH. The agreement between AMS and CPH deteriorated as the magnitude of the measured values increased, revealing a proportional (linear) bias (R2 = 0.512, p < 0.001). Neither the AMS nor the CPH measurements of the normalized maximum slope held a significant relationship with the occurrence of anastomotic leakage (median of 0.081 versus 0.074, p = 0.32 and 0.041 vs 0.042, p = 0.51, respectively). CONCLUSION: This is the first study to demonstrate technical differences in software implementations that can lead to discrepancies in ICG-FA quantification in human clinical cases. The possible variation among software-based quantification methods should be considered when interpreting studies that report quantitative ICG-FA parameters and derived thresholds, as there may be a limited external validity.

Quantitative perfusion assessment using indocyanine green during surgery - current applications and recommendations for future use.

PURPOSE: Incorrect assessment of tissue perfusion carries a significant risk of complications in surgery. The use of near-infrared (NIR) fluorescence imaging with Indocyanine Green (ICG) presents a possible solution. However, only through quantification of the fluorescence signal can an objective and reproducible evaluation of tissue perfusion be obtained. This narrative review aims to provide an overview of the available quantification methods for perfusion assessment using ICG NIR fluorescence imaging and to present an overview of current clinically utilized software implementations. METHODS: PubMed was searched for clinical studies on the quantification of ICG NIR fluorescence imaging to assess tissue perfusion. Data on the utilized camera systems and performed methods of quantification were collected. RESULTS: Eleven software programs for quantifying tissue perfusion using ICG NIR fluorescence imaging were identified. Five of the 11 programs have been described in three or more clinical studies, including Flow® 800, ROIs Software, IC Calc, SPY-Q™, and the Quest Research Framework®. In addition, applying normalization to fluorescence intensity analysis was described for two software programs. CONCLUSION: Several systems or software solutions provide a quantification of ICG fluorescence; however, intraoperative applications are scarce and quantification methods vary abundantly. In the widespread search for reliable quantification of perfusion with ICG NIR fluorescence imaging, standardization of quantification methods and data acquisition is essential.

Continuous vital sign monitoring after major abdominal surgery-Quantification of micro events.

INTRODUCTION: Millions of patients undergo major abdominal surgery worldwide each year, and the post-operative phase carries a high risk of respiratory and circulatory complications. Standard ward observation of patients includes vital sign registration at regular intervals. Patients may deteriorate between measurements, and this may be detected by continuous monitoring. The aim of this study was to compare the number of micro events detected by continuous monitoring to those documented by the widely used standardized Early Warning Score (EWS). METHODS: Fifty patients were continuously monitored with peripheral arterial oxygen saturation (SpO2 ), heart rate (HR), and respiratory rate (RR) the first 4 days after major abdominal cancer surgery. EWS was monitored as routine practice. Number and duration of events were analyzed using Fisher's exact test and Wilcoxon rank sum test. RESULTS: Continuous monitoring detected a SpO2 <92% in 98% of patients vs 16% of patients detected by EWS (P < .0001). Micro events of SpO2 <92% lasting longer than 60 minutes were found in 58% of patients by continuous monitoring vs 16% by the EWS (P < .0001). Fifty-two percent of patients had micro events of SpO2 <85% lasting longer than 10 minutes. Continuous monitoring found tachycardia in 60% of patients vs 6% by the EWS. Frequency of events for bradycardia, tachypnea, and bradypnea showed similar patterns. CONCLUSION: Very low SpO2 and tachycardia in post-operative patients are common and under-diagnosed by the EWS. Continuous monitoring can discover these micro events and potentially contribute to earlier detection and, potentially, result in prevention of clinical complications.

Recurrence following curative intended surgery for an adenocarcinoma in the gastroesophageal junction: a retrospective study.

Recurrence following a resection for an adenocarcinoma of the gastroesophageal junction leads to reduced long-term survival. This study aims to identify risk factors associated with recurrence, recurrence localization, time to recurrence, and long-term survival. All patients undergoing curative intended resection for an adenocarcinoma of the gastroesophageal junction at Rigshospitalet between June 2003 and December 2011 were identified through a prospectively maintained nationwide database and enrolled in this study. Only histologically verified recurrence was considered eligible. Recurrence within six months, microscopically incomplete resection margins, and death within eight weeks were excluded. A total of 348 patients were included in this study. Biopsy-verified recurrence occurred in 120 patients (34.5%), with 32 local (9.2%), and 88 distant (25.3%) recurrences. Lymph node metastases was associated with an increased risk of recurrence (hazard ratio; [95% confidence interval]: HR = 2.7; [1.7-4.3], P < 0.001). Median time to local versus distant recurrence was 18 months (interquartile range (IQR): 9-37 months) versus 17 months (IQR: 11-27 months), P = 0.96, respectively. A trend toward local recurrence was identified if patients had anastomotic leakage (HR = 2.64; [0.89-7.86], P = 0.08). Survival was inversely associated with recurrence, but a survival comparison between local and distant recurrences showed no significant difference: median survival time was 28 months (IQR: 17-43 months) versus 24 months (IQR: 16-36 months), P = 0.45, respectively. A trend toward local recurrence was seen if the patient had an anastomotic leakage event. However, no factors were associated with site-specific recurrence (local vs. distant).

Consensus conference statement on fluorescence-guided surgery (FGS) ESSO course on fluorescence-guided surgery.

BACKGROUND: Fluorescence-guided surgery (FGS) has emerged as an innovative technique with promising applications in various surgical specialties. However, clinical implementation is hampered by limited availability of evidence-based reference work supporting the translation towards standard-of-care use in surgical practice. Therefore, we developed a consensus statement on current applications of FGS. METHODS: During an international FGS course, participants anonymously voted on 36 statements. Consensus was defined as agreement ≥70% with participation grade of ≥80%. All participants of the questionnaire were stratified for user and handling experience within five domains of applicability (lymphatics & lymph node imaging; tissue perfusion; biliary anatomy and urinary tracts; tumor imaging in colorectal, HPB, and endocrine surgery, and quantification and (tumor-) targeted imaging). Results were pooled to determine consensus for each statement within the respective sections based on the degree of agreement. RESULTS: In total 43/52 (81%) course participants were eligible as voting members for consensus, comprising the expert panel (n = 12) and trained users (n = 31). Consensus was achieved in 17 out of 36 (45%) statements with highest level of agreement for application of FGS in tissue perfusion and biliary/urinary tract visualization (71% and 67%, respectively) and lowest within the tumor imaging section (0%). CONCLUSIONS: FGS is currently established for tissue perfusion and vital structure imaging. Lymphatics & lymph node imaging in breast cancer and melanoma are evolving, and tumor tissue imaging holds promise in early-phase trials. Quantification and (tumor-)targeted imaging are advancing toward clinical validation. Additional research is needed for tumor imaging due to a lack of consensus.

Choosing the best animal species to mimic clinical colon anastomotic leakage in humans: a qualitative systematic review.

BACKGROUND/AIMS: Animal models are valuable for studying pathogenic factors and preventive measures for colon anastomotic leakage. The suitability of the species as models varies greatly; however, no consensus exists on which species to use. The aim of this review was to evaluate different experimental animals for the study of clinical colon anastomotic leakage. METHODS: PubMed and REX database were searched up to October 2010 to identify studies evaluating clinical colon anastomotic leakage in animal models and textbooks on experimental animals, respectively. RESULTS: Functional models of clinical colon anastomotic leakage have been developed in the mouse, pig, rat, dog and rabbit. However, extreme interventions are needed in order to produce clinical leakage in the rat. CONCLUSION: Despite the wide use of the rat in this field of research, it seems that its resistance to intra-abdominal infection makes clinical leakage difficult to produce thus rendering the rat unsuited as a model. On the basis of the available literature, we recommend using mice as models mimicking clinical colon anastomotic leakage. Pigs may be an alternative; however, the existing models in this animal are less validated and clinically relevant.

Inadequate preoperative colonic evaluation for synchronous colorectal cancer.

BACKGROUND AND AIMS: Synchronous cancers (SC) are well known (2-11%) in patients with colorectal carcinoma (CRC). One study has shown that intraoperative palpation can miss up to 69% of the SC while other studies have shown altered planned surgical procedure due to preoperatively diagnosed synchronous lesions in 11-44%. The purpose of this study was to review all patients having surgery for CRC in our department since 2001, and to evaluate the extent of the perioperative colonic evaluation. MATERIALS AND METHODS: The records of all patients operated for CRC between Jan. 2001 and Dec. 2007 in our department were reviewed. Only patients with CRC were included. Information regarding pre-, per- and postoperative colonic evaluation were obtained and occurrences of SC were evaluated. RESULTS: Of the 534 patients included 124 (23%) patients had an impassable stenosis. Full preoperative colonic evaluation (FPCE) were done in 305 (26%) patients without stenosis. In 36 patients 39 SC were diagnosed. Seven SC were diagnosed postoperatively, of which five patients never had a FPCE. Three of these five patients had an inoperable SC, one patient died due to anastomosis leakage following re-operation and one patient had pulmonary embolism as a complication to re-operation. CONCLUSIONS: The results show that many patients (78%) never underwent FPCE, but also that many of these patients never had a full postoperative colonic evaluation. SC being overlooked can lead to increased morbidity and the possibility of advanced staging of the cancer which is also exemplified in this study.

A clinical evaluation of endoscopically placed self-expanding metallic stents in patients with acute large bowel obstruction.

BACKGROUND AND AIMS: Self-expanding metallic stents (SEMS) have since 1991 established themselves as an option in the treatment of large bowel obstruction. The aim of this study was to evaluate the use of SEMS in management of acute colorectal obstructions at a Danish Surgical Gastroenterology center. MATERIAL AND METHODS: Retrospective review of charts from all patients who, in the period Marts 2002 to December 2007 underwent insertion of a SEMS for an acute large bowel obstruction. RESULTS: Of 45 patients included, SEMS was intended as a bridge to surgery in 20 patients and as palliation in 25 patients. For malignant etiology, the SEMS procedure was a technical and clinical success in 97.4% of the cases. Complications occurred in 21%, mortality rate 2,6%. For benign etiology, the SEMS procedure was a technical success in 85.7%, and a clinical success in 71.4%. Complications occurred in 71.4% of the benign cases with a mortality rate of 28,6%. CONCLUSIONS: Placement of SEMS for acute large bowel obstruction with malignant etiology is an effective and safe procedure with low mortality and morbidity. However results for benign obstructions are questionable and more research is needed to determine the role of SEMS.

The occurrence of Enterococcus faecium and faecalis Is significantly associated With anastomotic leakage After pancreaticoduodenectomy.

BACKGROUND AND AIMS: Enterococcus has emerged as a virulent species; Enterococcus faecium especially has arisen as a source of nosocomial infections. Furthermore, specific Enterococcus faecalis species are significantly associated with anastomotic leakage in rodent studies. The objective of this study was to investigate whether the occurrence of Enterococci ( E. faecium and E. faecalis) obtained from drain samples was associated with leakage in humans undergoing pancreaticoduodenectomy. MATERIALS AND METHODS: All patients undergoing pancreaticoduodenectomy had a peritoneal drain sample sent for culturing between postoperative days 3 and 10. Postoperative pancreatic fistulas were defined and classified according to the International Study Group of Pancreatic Fistula. Bile leakage was radiologically verified. Postoperative complications were classified according to the Dindo-Clavien classification. RESULTS: A total of 70 patients were eligible and enrolled in this study. Anastomosis leakage was observed in 19 patients; 1 leakage corresponding to the hepaticojejunostomy and 18 pancreatic fistulas were identified. In total, 10 patients (53%) with leakage had Enterococci-positive drain samples versus 12 patients (24%) without leakage [odds ratio (OR) = 5.1, 95% confidence interval (CI) = 1.4-19.4, p = 0.02]. Preoperative biliary drainage with either endoscopic stenting or a percutaneous transhepatic cholangiography catheter was associated with the occurrence of Enterococci in drain samples (OR = 5.67, 95% CI = 1.8-12.9, p = 0.003), but preoperative biliary drainage was not associated with leakage (OR = 0.45, 95% CI = 0.1-1.7, p = 0.23). CONCLUSION: Enterococci in drain sample cultures in patients undergoing pancreaticoduodenectomy occurs significantly more among patients with anastomotic leakage compared to patients without leakage.

Severe Postoperative Complications may be Related to Mesenteric Traction Syndrome during Open Esophagectomy.

BACKGROUND: During abdominal surgery, traction of the mesenterium provokes mesenteric traction syndrome, including hypotension, tachycardia, and flushing, along with an increase in plasma prostacyclin (PGI2). We evaluated whether postoperative complications are related to mesenteric traction syndrome during esophagectomy. METHODS: Flushing, hemodynamic variables, and plasma 6-keto-PGF1α were recorded during the abdominal part of open ( n = 25) and robotically assisted ( n = 25) esophagectomy. Postoperative complications were also registered, according to the Clavien-Dindo classification. RESULTS: Flushing appeared in 17 (open) and 5 (robotically assisted) surgical cases ( p = 0.001). Mean arterial pressure was stable during both types of surgeries, but infusion of vasopressors during the first hour of open surgery was related to development of widespread (Grade II) flushing ( p = 0.036). For patients who developed flushing, heart rate and plasma 6-keto-PGF1α also increased ( p = 0.001 and p < 0.001, respectively). Furthermore, severe postoperative complications were related to Grade II flushing ( p = 0.037). CONCLUSION: Mesenteric traction syndrome manifests more frequently during open than robotically assisted esophagectomy, and postoperative complications appear to be associated with severe mesenteric traction syndrome.

The Multidisciplinary Team Conference's Decision on M-Staging in Patients with Gastric- and Gastroesophageal Cancer is not Accurate without Staging Laparoscopy.

BACKGROUND: The implementation of the multidisciplinary team conference has been shown to improve treatment outcome for patients with gastric- and gastroesophageal cancer. Likewise, the staging laparoscopy has increased the detection of patients with disseminated disease, that is, patients who do not benefit from a surgical resection. The aim of this study was to compare the multidisciplinary team conference's decision in respect of M-staging with the findings of the following staging laparoscopy. METHODS: Patients considered operable and resectable within the multidisciplinary team conference in the period 2010-2012 were retrospectively reviewed. Patient data were retrieved by searching for specific diagnosis and operation codes in the in-house system. The inclusion criteria were as follows: biopsy-verified cancer of the esophagus, gastroesophageal junction or stomach, and no suspicion of peritoneal carcinomatosis or liver metastases on multidisciplinary team conference before staging laparoscopy. Furthermore, an evaluation with staging laparoscopy was required. RESULTS: In total, 222 patients met the inclusion criteria. Most cancers were located in the gastroesophageal junction, n = 171 (77.0%), and most common with adenocarcinoma histology, n = 196 (88.3%). The staging laparoscopy was M1-positive for peritoneal carcinomatosis in eight patients (16.7%) with gastric cancer versus nine patients (5.3%) with gastroesophageal junction cancer. Furthermore, liver metastases were evident in zero patients (0.0%) and four patients (2.3%) with gastric- and gastroesophageal junction cancer, respectively. The staging laparoscopy findings regarding peritoneal carcinomatosis were significantly different between gastric- and gastroesophageal junction cancers, p = 0.01. No significant differences were found regarding T-/N-stage or histological tumor characteristics between the positive- and negative-staging laparoscopy group. CONCLUSION: The M-staging of the multidisciplinary team conference without staging laparoscopy lacks accuracy concerning peritoneal carcinomatosis. Staging laparoscopy remains an essential part of the preoperative detection of disseminated disease in patients with gastric- and gastroesophageal cancer.

Dysphagia is not a Valuable Indicator of Tumor Response after Preoperative Chemotherapy for R0 Resected Patients with Adenocarcinoma of the Gastroesophageal Junction.

BACKGROUND: Monitoring treatment response to preoperative chemotherapy is of utmost importance to avoid treatment toxicity, especially in non-responding patients. Currently, no reliable methods exist for tumor response assessment after preoperative chemotherapy. Therefore, the aim of this study was to evaluate dysphagia as a predictor of tumor response after preoperative chemotherapy and as a predictor of recurrence and survival. METHODS: Patients with adenocarcinoma of the gastroesophageal junction, treated between 2010 and 2012, were retrospectively reviewed. Dysphagia scores (Mellow-Pinkas) were obtained before and after three cycles of perioperative chemotherapy together with clinicopathological patient characteristics. A clinical response was defined as improvement of dysphagia by at least 1 score from the baseline. The tumor response was defined as down staging of T-stage from initial computer tomography (CT) scan (cT-stage) to pathologic staging of surgical specimen (pT-stage). Patients were followed until death or censored on June 27th, 2014. RESULTS: Of the 110 included patients, 59.1% had improvement of dysphagia after three cycles of perioperative chemotherapy, and 31.8% had a chemotherapy-induced tumor response after radical resection of tumor. Improvement of dysphagia was not correlated with the tumor response in the multivariate analysis (p = 0.23). Moreover, the presence of dysphagia was not correlated with recurrence (p = 0.92) or survival (p = 0.94) in the multivariate analysis. CONCLUSION: In our study, improvement of dysphagia was not valid for tumor response evaluation after preoperative chemotherapy and was not correlated with the tumor response. The presence of dysphagia does not seem to be a predictor of recurrence or survival.

Comparative Investigation of Postoperative Complications in Patients With Gastroesophageal Junction Cancer Treated With Preoperative Chemotherapy or Surgery Alone.

BACKGROUND AND AIM: Gastroesophageal junction cancer is one of the leading causes to cancer-related death and the prognosis is poor. However, progress has been made over the last couple of decades with the introduction of multimodality treatment and optimized surgery. Three-year survival rates have improved to 50% in patients receiving neoadjuvant therapy. Only a few studies have focused on the difference of postoperative complications in patients receiving neoadjuvant therapy in relation to a comparative surgery-only group. The aim of this study was to compare the prevalence of postoperative complications of patients with cancer at the gastroesophageal junction treated with either neoadjuvant chemotherapy or surgery alone in patients from "The Danish Clinical Registry of Carcinomas of the Esophagus, the Gastro-Esophageal Junction and the Stomach." MATERIALS AND METHODS: A historical follow-up study, comparing postoperative complications between two cohorts before and after implementation of chemotherapy was completed. RESULTS: In all, 180 consecutive patients treated with perioperative chemotherapy and a comparative surgery-only group of patients were identified from The Danish Clinical Registry of Carcinomas of the Esophagus, the Gastro-Esophageal Junction and the Stomach. No difference was found in demographics between the two groups, except for alcohol consumption and a lower T and N stage in the surgery-only group, and no difference in complication rates was found. Furthermore, no variable in the multivariate analysis was significantly associated with anastomotic leakage which was considered the most severe complication. CONCLUSION: Since perioperative chemotherapy does not appear to increase surgical complications, the future challenges include defining the optimal combination of chemo- and/or radiotherapy, but more importantly also to select the patients who will benefit the most from the different neoadjuvant strategies.

Post-endoscopic retrograde cholangiopancreaticography complications in liver transplanted patients, a single-center experience.

BACKGROUND: Complications in the biliary tract occur in 5%-30% after liver transplantation and the main part of the complications is successfully managed with endoscopic retrograde cholangiopancreaticography (ERCP). The incidence and risk factors for post-ERCP complications in liver transplantation patients are not well described. Our objective was to define the frequency of post-ERCP complications in liver transplantation patients at the Abdominal Center, Rigshospitalet, the only Liver Transplantation Center in Denmark. METHODS: Retrospective study of all ERCPs performed in liver transplantation patients during a 9-year period. RESULTS: A total of 292 ERCPs were included. Overall post-ERCP complications occurred in 24 procedures (8.2%): pancreatitis in 8 (2.7%), bleeding in 5 (1.7%), and cholangitis in 13 (4.5%) procedures. Simultaneous pancreatitis and cholangitis, and simultaneous bleeding and cholangitis occurred after two procedures, respectively. Multivariate analysis concerning overall complications identified biliary sphincterotomy (p = 0.006) and time since liver transplantation within 90 days postoperatively (p = 0.044) as risk factors for post-ERCP complications. Specifically concerning post-ERCP pancreatitis (PEP), it was found that pre-ERCP cholangitis was another independent risk factor for PEP (p = 0.026). Stent in the biliary tract prior to ERCP seemed to be protective (p = 0.041). CONCLUSIONS: Complications were of surprisingly mild degree. The rates of post-ERCP complications in our study were in line with previous studies with liver transplantation patients. Cholangitis prior to ERCP may be another risk factor for post-ERCP pancreatitis.

CT- and MR colonography.

BACKGROUND: Colorectal cancer is the second most frequent cancer and adenomas are widely accepted as precursors to colorectal cancer. Diagnosis and removal of adenomas are recommended to reduce cancer incidence and mortality. The current diagnostic methods include sigmoidoscopy and colonoscopy. Lately, CT- and MR colonography have emerged as non-invasive methods for colon imaging. METHODS: At present, CTC and MRC require bowel preparation. However, preliminary studies have been carried out without colon preparation. After the colon has been filled with air or contrast, the patient is scanned in the supine and prone positions. Data are then downloaded to a workstation for post processing and image-analysis. RESULTS: Results have shown a high sensitivity and specificity for polyps > or = 10 mm, comparable to the sensitivity of conventional colonoscopy and superior to double contrast barium enema. CONCLUSIONS: With the exponential development in computer processing power, CT- and MR colonography holds the promise for future colon examination with the advantages of non-invasiveness, no need for sedation, and probably no bowel preparation. A major disadvantage, however, is the radiation dose during CT colonography. Future developments with the use of "intelligent" computers, better resolution and faster examinations will make CT and/or MR colonography realistic options to replace conventional diagnostic colonoscopy.

Patient acceptance of MR colonography with improved fecal tagging versus conventional colonoscopy.

OBJECTIVE: Conventional colonoscopy (CC) is the gold standard for colonic examinations. However, patient acceptance is not high. Patient acceptance is influenced by several factors, notably anticipation and experience. This has led to the assumption that patient acceptance would be higher in non-invasive examinations such as MR/CT colonography (MRC/CTC) and perhaps even higher without bowel preparation. The purpose of this study was to evaluate patient acceptance of MRC with fecal tagging versus CC. MATERIALS AND METHODS: In a 14-month period, all patients first-time referred to our department for CC were asked to participate in the study. Two days prior to MRC, patients ingested an oral contrast mixture (barium/ferumoxsil) together with four meals each day. Standard bowel purgation was performed before CC. Before and after MRC and CC a number of questions were addressed. RESULTS: Sixty-four (34 men, 30 women) patients referred for CC participated in the study. 27% had some discomfort ingesting the contrast mixture, and 49% had some discomfort with the bowel purgation. As a future colonic examination preference, 71% preferred MRC, 13% preferred CC and 15% had no preference. If MRC was to be performed with bowel purgation, 75% would prefer MRC, 12% would prefer CC and 12% had no preference. CONCLUSION: This study shows that there is a potential gain in patient acceptance by using MRC for colonic examination, since MRC is considered less painful and less unpleasant than CC. In addition, the results indicate that patients in this study prefer fecal tagging instead of bowel purgation.

Differentiation between benign and malignant colon tumors using fast dynamic gadolinium-enhanced MR colonography; a feasibility study.

BACKGROUND: Colorectal cancer will present itself as a bowel obstruction in 16-23% of all cases. However, not all obstructing tumors are malignant and the differentiation between a benign and a malignant tumor can be difficult. The purpose of our study was to determine whether fast dynamic gadolinium-enhanced MR imaging combined with MR colonography could be used to differentiate a benign from a malignant obstructing colon tumor. METHODS: Patients with benign colon tumor stenosis, based on diverticulitis, were asked to participate in the study. The same number of patients with verified colorectal cancer was included. Both groups had to be scheduled for surgery to be included. Two blinded observers analyzed the tumors on MR by placing a region of interest in the tumor and a series of parameters were evaluated, e.g. wash-in, wash-out and time-to-peak. RESULTS: 14 patients were included. The wash-in and wash-out rates were significantly different between the benign and malignant tumors, and a clear distinction between benign and malignant disease was therefore possible by looking only at the MR data. Furthermore, MR colography evaluating the rest of the colon past the stenosis was possible with all patients. CONCLUSION: The results showed the feasibility of using fast dynamic gadolinium-enhanced MR imaging to differentiate between benign and malignant colonic tumors. With a high intra-class correlation and significant differences found on independent segments of the tumor, the method appears to be reproducible. Furthermore, the potential is big in performing a full preoperative colon evaluation even in patients with obstructing cancer. TRIAL NUMBER: NCT00114829.

Implementation of MR colonography.

BACKGROUND: MR colonography (MRC) is a promising method of examining the colon, but is limited to a few specialist centres. The purpose of this article was to describe the implementation of MRC with fecal tagging. MATERIALS AND METHODS: Patients referred for conventional colonoscopy (CC) were offered MRC with fecal tagging before CC. Two days before MRC patients ingested an oral contrast agent. Before and after MRC and CC a number of questions were addressed. MR images were rated by a blinded investigator. RESULTS: In 6 months, 30 consecutive patients were included. The median time in the MR suite was 44 min, 23 min for the MRC examination and 9 min for the evaluation. The median time for CC was 32 min. Sixty-six percent of the patients preferred MRC as the future method of examination, 10% preferred CC, 21% had no preferences. Of the oral contrast agents, barium sulphate with ferumoxsil was significantly better than barium sulphate alone. CONCLUSION: The majority of the patients found MRC less unpleasant than CC and a majority would prefer MRC over CC as a future colon examination. MRC also appears to be less time consuming to the patients and medical personnel than CC with post-procedural monitoring.