Indocyanine green fluorescence image processing techniques for breast cancer macroscopic demarcation.

Re-operation due to disease being inadvertently close to the resection margin is a major challenge in breast conserving surgery (BCS). Indocyanine green (ICG) fluorescence imaging could be used to visualize the tumor boundaries and help surgeons resect disease more efficiently. In this work, ICG fluorescence and color images were acquired with a custom-built camera system from 40 patients treated with BCS. Images were acquired from the tumor in-situ, surgical cavity post-excision, freshly excised tumor and histopathology tumour grossing. Fluorescence image intensity and texture were used as individual or combined predictors in both logistic regression (LR) and support vector machine models to predict the tumor extent. ICG fluorescence spectra in formalin-fixed histopathology grossing tumor were acquired and analyzed. Our results showed that ICG remains in the tissue after formalin fixation. Therefore, tissue imaging could be validated in freshly excised and in formalin-fixed grossing tumor. The trained LR model with combined fluorescence intensity (pixel values) and texture (slope of power spectral density curve) identified the tumor's extent in the grossing images with pixel-level resolution and sensitivity, specificity of 0.75 ± 0.3, 0.89 ± 0.2.This model was applied on tumor in-situ and surgical cavity (post-excision) images to predict tumor presence.

The Impact of Temporal Variation in Indocyanine Green Administration on Tumor Identification During Fluorescence Guided Breast Surgery.

BACKGROUND: On average, 21% of women in the USA treated with Breast Conserving Surgery (BCS) undergo a second operation because of close positive margins. Tumor identification with fluorescence imaging could improve positive margin rates through demarcating location, size, and invasiveness of tumors. We investigated the technique's diagnostic accuracy in detecting tumors during BCS using intravenous indocyanine green (ICG) and a custom-built fluorescence camera system. METHODS: In this single-center prospective clinical study, 40 recruited BCS patients were sub-categorized into two cohorts. In the first 'enhanced permeability and retention' (EPR) cohort, 0.25 mg/kg ICG was injected ~ 25 min prior to tumor excision, and in the second 'angiography' cohort, ~ 5 min prior to tumor excision. Subsequently, an in-house imaging system was used to image the tumor in situ prior to resection, ex vivo following resection, the resection bed, and during grossing in the histopathology laboratory to compare the technique's diagnostic accuracy between the cohorts. RESULTS: The two cohorts were matched in patient and tumor characteristics. The majority of patients had invasive ductal carcinoma with concomitant ductal carcinoma in situ. Tumor-to-background ratio (TBR) in the angiography cohort was superior to the EPR cohort (TBR = 3.18 ± 1.74 vs 2.10 ± 0.92 respectively, p = 0.023). Tumor detection reached sensitivity and specificity scores of 0.82 and 0.93 for the angiography cohort and 0.66 and 0.90 for the EPR cohort, respectively (p = 0.1051 and p = 0.9099). DISCUSSION: ICG administration timing during the angiography phase compared with the EPR phase improved TBR and diagnostic accuracy. Future work will focus on image pattern analysis and adaptation of the camera system to targeting fluorophores specific to breast cancer.

Perfect Registration Leads to Imperfect Performance: A Randomized Trial of Multimodal Intraoperative Image Guidance.

OBJECTIVE: To compare surgical safety and efficiency of 2 image guidance modalities, perfect augmented reality (AR) and side-by-side unregistered image guidance (IG), against a no guidance control (NG), when performing a simulated laparoscopic cholecystectomy (LC). BACKGROUND: Image guidance using AR offers the potential to improve understanding of subsurface anatomy, with positive ramifications for surgical safety and efficiency. No intra-abdominal study has demonstrated any advantage for the technology. Perfect AR cannot be provided in the operative setting in a patient; however, it can be generated in the simulated setting. METHODS: Thirty-six experienced surgeons performed a baseline LC using the LapMentor simulator before randomization to 1 of 3 study arms: AR, IG, or NG. Each performed 3 further LC. Safety and efficiency-related simulator metrics, and task workload (SURG-TLX) were collected. RESULTS: The IG group had a shorter total instrument path length and fewer movements than NG and AR groups. Both IG and NG took a significantly shorter time than AR to complete dissection of Calot triangle. Use of IG and AR resulted in significantly fewer perforations and serious complications than the NG group. IG had significantly fewer perforations and serious complications than the AR group. Compared with IG, AR guidance was found to be significantly more distracting. CONCLUSION: Side-by-side unregistered image guidance (IG) improved safety and surgical efficiency in a simulated setting when compared with AR or NG. IG provides a more tangible opportunity for integrating image guidance into existing surgical workflow as well as delivering the safety and efficiency benefits desired.

Enhancing Safety Culture Through Improved Incident Reporting: A Case Study In Translational Research.

The Imperial College Healthcare National Health Service Trust, a large health care provider in London, together with an academic research unit, used a learning health systems cycle of interventions. The goals were to improve patient safety incident reporting and learning and shape a more just organizational safety culture. Following a phase of feedback gathering from front-line staff, seven evidence-based interventions were implemented and evaluated from October 2016 to August 2018. Indicators of safety culture, incident reporting rates, and reported rates of harm to patients and "never events" (events that should not happen in medical practice) were continuously monitored. In this article we report on this initiative, including its early results. We observed improvement on some measures of safety culture and incident reporting rates. Staff members' perceptions of six of the seven interventions were positive. The intervention exercise demonstrated the importance of health care policies in supporting local ownership of safety culture and encouraging the application of rigorous research standards.

Cohort analysis of outcomes in 69†490 emergency general surgical admissions across an international benchmarking collaborative.

OBJECTIVE: This study aims to use the Dr Foster Global Comparators Network (GC) database to examine differences in outcomes following high-risk emergency general surgery (EGS) admissions in participating centres across 3 countries and to determine whether hospital infrastructure factors can be linked to the delivery of high-quality care. DESIGN: A retrospective cohort analysis of high-risk EGS admissions using GC's international administrative data set. SETTING: 23 large hospitals in Australia, England and the USA. METHODS: Discharge data for a cohort of high-risk EGS patients were collated. Multilevel hierarchical logistic regression analysis was performed to examine geographical and structural differences between GC hospitals. RESULTS: 69 490 patients, admitted to 23 centres across Australia, England and the USA from 2007 to 2012, were identified. For all patients within this cohort, outcomes defined as: 7-day and 30-day inhospital mortality, readmission and length of stay appeared to be superior in US centres. A subgroup of 19 082 patients (27%) underwent emergency abdominal surgery. No geographical differences in mortality were seen at 7 days in this subgroup. 30-day mortality (OR=1.47, p<0.01) readmission (OR=1.42, p<0.01) and length of stay (OR=1.98, p<0.01) were worse in English units. Patient factors (age, pathology, comorbidity) were significantly associated with worse outcome as were structural factors, including low intensive care unit bed ratios, high volume and interhospital transfers. Having dedicated EGS teams cleared of elective commitments with formalised handovers was associated with shorter length of stay. CONCLUSIONS: Key factors that influence outcomes were identified. For patients who underwent surgery, outcomes were similar at 7 days but not at 30 days. This may be attributable to better infrastructure and resource allocation towards EGS in the US and Australian centres.

The role of technology in minimally invasive surgery: state of the art, recent developments and future directions.

The diffusion of minimally invasive surgery has thrived in recent years, providing substantial benefits over traditional techniques for a number of surgical interventions. This rapid growth has been possible due to significant advancements in medical technology, which partly solved some of the technical and clinical challenges associated with minimally invasive techniques. The issues that still limit its widespread adoption for some applications include the limited field of view; reduced manoeuvrability of the tools; lack of haptic feedback; loss of depth perception; extended learning curve; prolonged operative times and higher financial costs. The present review discusses some of the main recent technological advancements that fuelled the uptake of minimally invasive surgery, focussing especially on the areas of imaging, instrumentation, cameras and robotics. The current limitations of state-of-the-art technology are identified and addressed, proposing future research directions necessary to overcome them.

A Systematic Review of the Impact of Dedicated Emergency Surgical Services on Patient Outcomes.

OBJECTIVE: This review aims to assess the impact of implementing dedicated emergency surgical services, in particular acute care surgery, on clinical outcomes. BACKGROUND: The optimal model for delivering high-quality emergency surgical care remains unknown. Acute Care Surgery (ACS) is a health care model combining emergency general surgery, trauma, and critical care. It has been adopted across the United States in the management of surgical emergencies. METHOD: A systematic review was performed after PRISMA recommendations using the MEDLINE, Embase, and Psych-Info databases. Studies assessing different care models and institutional factors affecting the delivery of emergency general surgery were included. RESULTS: Twenty-seven studies comprising 744,238 patients were included in this review. In studies comparing ACS with traditional practice, mortality and morbidity were improved. Moreover, time to senior review, delays to operating theater, and financial expenditure were often reduced. The elements of ACS models varied but included senior clinicians present onsite during office hours and dedicated to emergency care while on-call. Referrals were made to specialist centers with primary surgical assessments taking place on surgical admissions units rather than in the emergency department. Twenty-four-hour access to dedicated emergency operating rooms was also described. CONCLUSIONS: ACS models as well as centralized units and hospitals with dedicated emergency operating rooms, access to radiology and intensive care facilities (ITU) are all factors associated with improved clinical and financial outcomes in the delivery of emergency general surgery. There is, however, no consensus on the elements that constitute an ideal ACS model and how it can be implemented into current surgical practice.

Evaluating a Novel 3D Stereoscopic Visual Display for Transanal Endoscopic Surgery: A Randomized Controlled Crossover Study.

OBJECTIVE: To compare surgical performance with transanal endoscopic surgery (TES) using a novel 3-dimensional (3D) stereoscopic viewer against the current modalities of a 3D stereoendoscope, 3D, and 2-dimensional (2D) high-definition monitors. BACKGROUND: TES is accepted as the primary treatment for selected rectal tumors. Current TES systems offer a 2D monitor, or 3D image, viewed directly via a stereoendoscope, necessitating an uncomfortable operating position. To address this and provide a platform for future image augmentation, a 3D stereoscopic display was created. METHODS: Forty participants, of mixed experience level, completed a simulated TES task using 4 visual displays (novel stereoscopic viewer and currently utilized stereoendoscope, 3D, and 2D high-definition monitors) in a randomly allocated order. Primary outcome measures were: time taken, path length, and accuracy. Secondary outcomes were: task workload and participant questionnaire results. RESULTS: Median time taken and path length were significantly shorter for the novel viewer versus 2D and 3D, and not significantly different to the traditional stereoendoscope. Significant differences were found in accuracy, task workload, and questionnaire assessment in favor of the novel viewer, as compared to all 3 modalities. CONCLUSIONS: This novel 3D stereoscopic viewer allows surgical performance in TES equivalent to that achieved using the current stereoendoscope and superior to standard 2D and 3D displays, but with lower physical and mental demands for the surgeon. Participants expressed a preference for this system, ranking it more highly on a questionnaire. Clinical translation of this work has begun with the novel viewer being used in 5 TES patients.

Development and implementation of the Structured Training Trainer Assessment Report (STTAR) in the English National Training Programme for laparoscopic colorectal surgery.

BACKGROUND: There is a lack of educational tools available for surgical teaching critique, particularly for advanced laparoscopic surgery. The aim was to develop and implement a tool that assesses training quality and structures feedback for trainers in the English National Training Programme for laparoscopic colorectal surgery. METHODS: Semi-structured interviews were performed and analysed, and items were extracted. Through the Delphi process, essential items pertaining to desirable trainer characteristics, training structure and feedback were determined. An assessment tool (Structured Training Trainer Assessment Report-STTAR) was developed and tested for feasibility, acceptability and educational impact. RESULTS: Interview transcripts (29 surgical trainers, 10 trainees, four educationalists) were analysed, and item lists created and distributed for consensus opinion (11 trainers and seven trainees). The STTAR consisted of 64 factors, and its web-based version, the mini-STTAR, included 21 factors that were categorised into four groups (training structure, training behaviour, trainer attributes and role modelling) and structured around a training session timeline (beginning, middle and end). The STTAR (six trainers, 48 different assessments) demonstrated good internal consistency (α = 0.88) and inter-rater reliability (ICC = 0.75). The mini-STTAR demonstrated good inter-item reliability (α = 0.79) and intra-observer reliability on comparison of 85 different trainer/trainee combinations (r = 0.701, p = <0.001). Both were found to be feasible and acceptable. The educational report for trainers was found to be useful (4.4 out of 5). CONCLUSIONS: An assessment tool that evaluates training quality was developed and shown to be reliable, acceptable and of educational value. It has been successfully implemented into the English National Training Programme for laparoscopic colorectal surgery.

The impact of expert visual guidance on trainee visual search strategy, visual attention and motor skills.

Minimally invasive and robotic surgery changes the capacity for surgical mentors to guide their trainees with the control customary to open surgery. This neuroergonomic study aims to assess a "Collaborative Gaze Channel" (CGC); which detects trainer gaze-behavior and displays the point of regard to the trainee. A randomized crossover study was conducted in which twenty subjects performed a simulated robotic surgical task necessitating collaboration either with verbal (control condition) or visual guidance with CGC (study condition). Trainee occipito-parietal (O-P) cortical function was assessed with optical topography (OT) and gaze-behavior was evaluated using video-oculography. Performance during gaze-assistance was significantly superior [biopsy number: (mean ± SD): control = 5.6 ± 1.8 vs. CGC = 6.6 ± 2.0; p < 0.05] and was associated with significantly lower O-P cortical activity [ΔHbO2 mMol × cm [median (IQR)] control = 2.5 (12.0) vs. CGC 0.63 (11.2), p < 0.001]. A random effect model (REM) confirmed the association between guidance mode and O-P excitation. Network cost and global efficiency were not significantly influenced by guidance mode. A gaze channel enhances performance, modulates visual search, and alleviates the burden in brain centers subserving visual attention and does not induce changes in the trainee's O-P functional network observable with the current OT technique. The results imply that through visual guidance, attentional resources may be liberated, potentially improving the capability of trainees to attend to other safety critical events during the procedure.

Inattention blindness in surgery.

BACKGROUND: Inattention blindness (IB) can be defined as the failure to perceive an unexpected object when attention is focussed on another object or task. The principal aim of this study was to determine the effect of cognitive load and surgical image guidance on operative IB. METHODS: Using a randomised control study design, participants were allocated to a high or low cognitive load group and subsequently to one of three augmented reality (AR) image guidance groups (no guidance, wireframe overlay and solid overlay). Randomised participants watched a segment of video from a robotic partial nephrectomy. Those in the high cognitive load groups were asked to keep a count of instrument movements, while those in the low cognitive load groups were only asked to watch the video. Two foreign bodies were visible within the operative scene: a swab, within the periphery of vision; and a suture, in the centre of the operative scene. Once the participants had finished watching the video, they were asked to report whether they had observed a swab or suture. RESULTS: The overall level of prompted inattention blindness was 74 and 10 % for the swab and suture, respectively. Significantly higher levels of IB for the swab were seen in the high versus the low cognitive load groups, but not for the suture (8 vs. 47 %, p < 0.001 and 90 vs. 91 %, p = 1.000, for swab and suture, respectively). No significant difference was seen between image guidance groups for attention of the swab or suture (29 vs. 20 %, p = 0.520 and 22 vs. 22 %, p = 1.000, respectively). CONCLUSIONS: The overall effect of IB on operative practice appeared to be significant, within the context of this study. When examining for the effects of AR image guidance and cognitive load on IB, only the latter was found to have significance.

A randomized controlled study to establish the effect of articulating instruments on performance in single-incision laparoscopic surgery.

OBJECTIVE: In single-incision laparoscopic surgery (SILS), operating through 1 incision presents ergonomic challenges. No consensus exists on whether articulating instruments (ARTs) may help. This study evaluated their effect on simulated SILS, hypothesizing that they would affect performance and workload. DESIGN: Surgeons were randomized to 2 straight instruments (STRs), 1 ART and 1 STR, or 2 ARTs. After baseline testing, 25 repetitions of the Fundamentals of Laparoscopic Surgery (FLS) peg-transfer (PEG) task and 5 repetitions of the short-hand for the FLS pattern-cutting task (CIRCLE) were performed. Primary outcomes were maximum FLS PEG scores, CIRCLE times and errors, and Imperial College Surgical Assessment Device hand motion analysis. National Aeronautics and Space Administration (NASA) Raw Task Load Index (RTLX) questionnaires evaluated a secondary outcome--workload. SETTING: The trial took place in a simulated operating theater within the Academic Surgical Unit at St Mary's Hospital, London, UK. PARTICIPANTS: Eligible surgeons had completed at least 5 laparoscopic cases as a primary operator. Surgeons were stratified by laparoscopic experience into intermediate (less than 25 previous procedures as primary operator) or advanced (25 procedures or more). A total of 21 surgeons were recruited and randomized; 7 of them to each instrument combination group. All surgeons completed PEG, and 5 from each group completed CIRCLE. RESULTS: Groups' baseline PEG scores were similar (p = 0.625). STR-ART achieved higher maximum PEG scores than STR or ART did (median = 236 vs 198 vs 193, respectively, p = 0.002). Fastest CIRCLE times were similar (median = 190s vs 130s vs 186s, p = 0.129) as were minimum errors (median = 1 vs 2 vs 3, p = 0.101). For PEG, Imperial College Surgical Assessment Device demonstrated similar total path lengths (median = 12.3m vs 12.3m vs 16.0m, p = 0.545) and total numbers of movements (median = 89.6 vs 86.4 vs 171, p = 0.080). Groups' NASA Raw Task Load Index scores were similar (p = 0.708). CONCLUSIONS: Combining 1 STR and 1 ART improved SILS performance in the PEG task. Therefore, this may be the optimum instrument configuration for use within some clinical SILS applications.

Is It Time to Centralize High-risk Cancer Care in the United States? Comparison of Outcomes of Esophagectomy Between England and the United States.

OBJECTIVE: To determine the difference in in-hospital mortality and length of hospital stay (LOS) after esophagectomy between the United States and England. BACKGROUND: Since 2001, complex procedures such as esophagectomy have been centralized in England, but in the United States no formal plan for centralization exists. METHODS: Patients who underwent esophagectomy for cancer between 2005 and 2010 were identified from the Nationwide Inpatient Sample (United States) and the Hospital Episodes Statistics (England). In-hospital mortality and LOS were compared. RESULTS: There were 7433 esophagectomies performed in 66 English hospitals and 5858 resections in 775 US hospitals; median number of resections per center per year was 17.5 in England and 2 in the United States. In-hospital mortality was greater in US hospitals (5.50% vs 4.20%, P = 0.001). In multiple regression analysis, predictors of mortality included patient age, comorbidities, hospital volume, and surgery performed in the United States [odds ratio (OR) = 1.20 (1.02-1.41), P = 0.03]. Median LOS was greater in the English hospitals (15 vs 12 days, P < 0.001). However, when subset analysis was done on high-volume centers in both health systems, mortality was significantly better in US hospitals (2.10% vs 3.50%, P = 0.02). LOS was also seen to decrease in the US high-volume centers but not in England. CONCLUSIONS: The findings from this international comparison suggest that centralization of high-risk cancer surgery to centers of excellence with a high procedural volume translates into an improved clinical outcome. These findings should be factored into discussions regarding future service configuration of major cancer surgery in the United States.

Quantifying innovation in surgery.

OBJECTIVES: The objectives of this study were to assess the applicability of patents and publications as metrics of surgical technology and innovation; evaluate the historical relationship between patents and publications; develop a methodology that can be used to determine the rate of innovation growth in any given health care technology. BACKGROUND: The study of health care innovation represents an emerging academic field, yet it is limited by a lack of valid scientific methods for quantitative analysis. This article explores and cross-validates 2 innovation metrics using surgical technology as an exemplar. METHODS: Electronic patenting databases and the MEDLINE database were searched between 1980 and 2010 for "surgeon" OR "surgical" OR "surgery." Resulting patent codes were grouped into technology clusters. Growth curves were plotted for these technology clusters to establish the rate and characteristics of growth. RESULTS: The initial search retrieved 52,046 patents and 1,801,075 publications. The top performing technology cluster of the last 30 years was minimally invasive surgery. Robotic surgery, surgical staplers, and image guidance were the most emergent technology clusters. When examining the growth curves for these clusters they were found to follow an S-shaped pattern of growth, with the emergent technologies lying on the exponential phases of their respective growth curves. In addition, publication and patent counts were closely correlated in areas of technology expansion. CONCLUSIONS: This article demonstrates the utility of publically available patent and publication data to quantify innovations within surgical technology and proposes a novel methodology for assessing and forecasting areas of technological innovation.

Meta analysis of robot-assisted versus conventional laparoscopic fundoplication in children.

BACKGROUND: Minimally invasive fundoplication may be performed using either a robot-assisted (RF) or conventional laparoscopic (LF) technique. Evidence comparing RF and LF in children remains unclear. This study aims to elucidate the comparative safety and efficacy of RF versus LF by systematic review and meta-analysis. METHODS: Comparative studies investigating RF versus LF in children were identified from multiple electronic literature databases. Meta-analysis was performed using random effects modeling. Safety parameters investigated were post-operative morbidity and intra-operative conversions. Efficacy outcomes of interest were operative success, re-operation, post-operative complications, length of hospital stay (LOS), total operating time (OT), analgesia requirement, and cost. RESULTS: Six observational studies met inclusion criteria, reporting outcomes of 297 children. No randomized controlled trials were identified. Pooled analysis determined no statistically significant differences between RF and LF for conversions, OT, LOS, and post-operative complications. There was no standardized follow up beyond the early post-operative period to enable data synthesis for remaining outcomes of interest. Limited evidence indicates higher costs with RF. CONCLUSIONS: Safety and short-term efficacy seem comparable between RF and LF in children. There is insufficient evidence to assess comparative effectiveness for many important procedure specific outcome measures. Higher quality and longer follow-up studies are required.

Augmented reality partial nephrectomy: examining the current status and future perspectives.

A minimal access approach to partial nephrectomy has historically been under-utilized, but is now becoming more popular with the growth of robot-assisted laparoscopy. One of the criticisms of minimal access partial nephrectomy is the loss of haptic feedback. Augmented reality operating environments are forecast to play a major enabling role in the future of minimal access partial nephrectomy by integrating enhanced visual information to supplement this loss of haptic sensation. In this article, we systematically examine the current status of augmented reality in partial nephrectomy by identifying existing research challenges and exploring future agendas for this technology to achieve wider clinical translation.

Surgical technology and operating-room safety failures: a systematic review of quantitative studies.

BACKGROUND: Surgical technology has led to significant improvements in patient outcomes. However, failures in equipment and technology are implicated in surgical errors and adverse events. We aim to determine the proportion and characteristics of equipment-related error in the operating room (OR) to further improve quality of care. METHODS: A systematic review of the published literature yielded 19 362 search results relating to errors and adverse events occurring in the OR, from which 124 quantitative error studies were selected for full-text review and 28 were finally selected. RESULTS: Median total errors per procedure in independently-observed prospective studies were 15.5, interquartile range (IQR) 2.0-17.8. Failures of equipment/technology accounted for a median 23.5% (IQR 15.0%-34.1%) of total error. The median number of equipment problems per procedure was 0.9 (IQR 0.3-3.6). From eight studies, subdivision of equipment failures was possible into: equipment availability (37.3%), configuration and settings (43.4%) and direct malfunctioning (33.5%). Observed error rates varied widely with study design and with type of operation: those with a greater burden of technology/equipment tended to show higher equipment-related error rates. Checklists (or similar interventions) reduced equipment error by mean 48.6% (and 60.7% in three studies using specific equipment checklists). CONCLUSIONS: Equipment-related failures form a substantial proportion of all error occurring in the OR. Those procedures that rely more heavily on technology may bear a higher proportion of equipment-related error. There is clear benefit in the use of preoperative checklist-based systems. We propose the adoption of an equipment check, which may be incorporated into the current WHO checklist.

Image-guided robotic interventions for prostate cancer.

Robotic prostatectomy is a common surgical treatment for men with prostate cancer, with some studies estimating that 80% of prostatectomies now performed in the USA are done so robotically. Despite the technical advantages offered by robotic systems, functional and oncological outcomes of prostatectomy can still be improved further. Alternative minimally invasive treatments that have also adopted robotic platforms include brachytherapy and high-intensity focused ultrasonography (HIFU). These techniques require real-time image guidance--such as ultrasonography or MRI--to be truly effective; issues with software compatibility as well as image registration and tracking currently limit such technologies. However, image-guided robotics is a fast-growing area of research that combines the improved ergonomics of robotic systems with the improved visualization of modern imaging modalities. Although the benefits of a real-time image-guided robotic system to improve the precision of surgical interventions are being realized, the clinical usefulness of many of these systems remains to be seen.

Diagnostic accuracy and value of magnetic resonance imaging (MRI) in planning exenterative pelvic surgery for advanced colorectal cancer.

PURPOSE: To assess the diagnostic accuracy of magnetic resonance imaging (MRI) in detecting colorectal tumour invasion according to seven intrapelvic compartments for planning exenterative pelvic surgery. METHOD: Sixty-three consecutive patients underwent preoperative MRI planning for exenterative surgery, defined as operative excision beyond conventional mesenteric planes for locally advanced (n=23) and recurrent (n=41) pelvic colorectal cancer. The institutional research committee approved of the study and waived the need for a consent form as the images were retrospectively assessed. Two radiologists reported tumour invasion for each of seven anatomic surgical resection compartments, blinded to histopathology and the intraoperative findings. Sensitivity, specificity and predictive values were calculated for the seven intrapelvic compartments. Cox regression analysis was used to calculate the risk of death and recurrence. Overall interobserver agreement was assessed using Cohen's Kappa coefficient (k). RESULTS: The sensitivity of MRI was ≥93.3% in all but the lateral compartment where it was 89.3%. Specificity for the posterior (82.2%) and anterior compartments below the peritoneal reflection (86.4%) was lower compared to the other compartments. Agreement between the two radiologists was found to be good or very good for all compartments (k>0.72). An MRI diagnosis of tumour invasion in the anterior compartment above the peritoneal reflection was associated with a poorer survival (p=0.012). CONCLUSION: MRI is accurate in predicting the extent of colorectal tumour within the pelvis and therefore can be used to determine the type of surgery required for curative resection. It should always be used to stage patients with advanced colorectal pelvic cancer.