Influencing factors in surgical decision-making: a qualitative analysis of colorectal surgeons' experiences of postoperative complications.

AIM: When making anastomotic decisions in rectal cancer surgery, surgeons must consider the risk of anastomotic leakage, which bears implications for the patient's quality of life, cancer recurrence and, potentially, death. The aim of this study was to investigate the views of colorectal surgeons on how their individual attributes (e.g. experience, personality traits) may influence their decision-making and experience of complications. METHOD: This qualitative study used individual interviews for data collection. Purposive sampling was used to invite certified UK-based colorectal surgeons to participate. Participants were recruited until ongoing data review indicated no new codes were generated, suggesting data sufficiency. Data were analysed thematically following Braun and Clarke's six-step framework. RESULTS: Seventeen colorectal surgeons (eight female, nine male) participated. Two key themes with relevant subthemes were identified: (1) personal attributes influencing variation in decision-making (e.g. demographics, personality) and (2) the influence of complications on decision-making. Surgeons described variation in the management of complications based upon their personal attributes, which included factors such as gender, experience and subspeciality interests. Surgeons described the detrimental impact of anastomotic leakage on their mental and physical health. Experience of anastomotic leakage influences future decision-making and is associated with changes in practice even when a technical error is not identified. CONCLUSION: Colorectal surgeons consider anastomotic leaks to be personal 'failures', which has a negative impact on surgeon welfare. Better understanding of how surgeons make difficult decisions, and how surgeons respond to and learn from complications, is necessary to identify 'personalized' methods of supporting surgeons at all career stages, which may improve patient outcomes.

Poor outcomes in patients with sepsis undergoing emergency laparotomy and laparoscopy are attenuated by faster time to care measures.

AIM: Emergency laparotomy and laparoscopy (EmLap) are amongst the commonest surgical procedures, with high prevalence of sepsis and hence poorer outcomes. However, whether time taken to receive care influences outcomes in patients requiring antibiotics for suspected infection remains largely unexplored. The aim of this work was to determine whether (1) time to care contributes to outcome differences between patients with and without suspected infection and (2) its impact on outcomes only amongst those with suspected infection. METHOD: Clinical information was retrospectively obtained from the 2017-2018 Emergency Laparotomy and Laparoscopic Scottish Audit (ELLSA). Time to care referred to six temporal variables describing radiological investigation, anaesthetic triage and surgical management. Outcome measures [mortality, readmission, hospital death, postoperative destination and length of stay (LoS)] were compared using adjusted and unadjusted regression analyses to determine whether the outcome differences could be explained by faster or slower time to care. RESULTS: Amongst 2243 EmLap patients [median age 65 years (interquartile range 51-75 years), 51.1% female], 892 (39.77%) received antibiotics for suspected infection. Although patients with suspected infection had faster time to care (all p ≤ 0.001) and worse outcomes compared with those who did not, outcome differences were not statistically significant when accounted for time (all p > 0.050). Amongst those who received antibiotics, faster time to care was also associated with decreased risk of postoperative intensive care unit (ICU) stay and shorter LoS (all p < 0.050). CONCLUSION: Worse outcomes associated with infection in EmLap patients were attenuated by faster time to care, which additionally reduced the LoS and ICU stay risk amongst those with suspected infection.

Patient-reported impact of emergency laparotomy on employment and health status 1 year after surgery.

BACKGROUND: Whilst there has been significant improvement in mortality outcomes after emergency laparotomy, there is little information on longer term outcomes in the year after discharge. The main aim of the study was to assess the impact that an emergency laparotomy has on patients' and employment and health status 1 year after surgery. METHODS: This study was a questionnaire study conducted in a single centre district general hospital of patients who had undergone an emergency laparotomy between October 2015 and December 2016. Patients were included according to the National Emergency Laparotomy Audit criteria. At screening, patients who were alive at 1 year and had the capacity to consent were approached between January and December 2017. Patients underwent a researcher-led telephone interview using a semi-structured questionnaire to assess the impact of emergency laparotomy on overall, general and physical health (Glasgow Benefit Inventory) as well as employment status. The symptoms that patients experienced and their impact were also recorded. RESULTS: Forty-two patients responded to and completed the questionnaire. Just over one-third of patients experienced a deterioration in their general or physical health and 21% of patients experienced a change in employment. Factors which significantly impacted on health status were stoma issues, postoperative morbidity and a change in employment (p < 0.05). The main symptoms which patients identified as being troublesome were altered bowel habit and stoma issues with a resultant social and psychological impact. CONCLUSIONS: One-third of patients experienced a deterioration in their psychosocial and physical health status as well as a change in employment during the first-year postsurgery. Larger research studies are required to define the impact of emergency laparotomy on patients in the longer term and more research is needed to improve perioperative rehabilitation in the postoperative period to ensure optimal functional gain after technically successful surgery.

Exploring variation in surgical practice: does surgeon personality influence anastomotic decision-making?

BACKGROUND: Decision-making under uncertainty may be influenced by an individual's personality. The primary aim was to explore associations between surgeon personality traits and colorectal anastomotic decision-making. METHODS: Colorectal surgeons worldwide participated in a two-part online survey. Part 1 evaluated surgeon characteristics using the Big Five Inventory to measure personality (five domains: agreeableness; conscientiousness; extraversion; emotional stability; openness) in response to scenarios presented in Part 2 involving anastomotic decisions (i.e. rejoining the bowel with/without temporary stomas, or permanent diversion with end colostomy). Anastomotic decisions were compared using repeated-measure ANOVA. Mean scores of traits domains were compared with normative data using two-tailed t tests. RESULTS: In total, 186 surgeons participated, with 127 surgeons completing both parts of the survey (68.3 per cent). One hundred and thirty-one surgeons were male (70.4 per cent) and 144 were based in Europe (77.4 per cent). Forty-one per cent (77 surgeons) had begun independent practice within the last 5 years. Surgeon personality differed from the general population, with statistically significantly higher levels of emotional stability (3.25 versus 2.97 respectively), lower levels of agreeableness (3.03 versus 3.74), extraversion (2.81 versus 3.38) and openness (3.19 versus 3.67), and similar levels of conscientiousness (3.42 versus 3.40 (all P <0.001)). Female surgeons had significantly lower levels of openness (P <0.001) than males (3.06 versus 3.25). Personality was associated with anastomotic decision-making in specific scenarios. CONCLUSION: Colorectal surgeons have different personality traits from the general population. Certain traits seem to be associated with anastomotic decision-making but only in specific scenarios. Further exploration of the association of personality, risk-taking, and decision-making in surgery is necessary.

Comparison of the clinical frailty score (CFS) to the National Emergency Laparotomy Audit (NELA) risk calculator in all patients undergoing emergency laparotomy.

AIM: There is evolving evidence that preoperative frailty predicts outcomes of older adults undergoing emergency laparotomy (EmLap). We assessed frailty scoring in an emergency surgical population that included patients of all ages and then compared this to an established perioperative prognostic score. METHOD: Data from the prospective Emergency Laparoscopic and Laparotomy Scottish Audit (ELLSA; November 2017-October 2018) was used. All adults over 18 were included. Frailty was measured using 7-point clinical frailty score (CFS). OUTCOME MEASURES: 30-day mortality, hospital length of stay (LOS), 30-day readmission. Areas under the receiver-operating characteristic (ROC) curves were calculated for CFS (1-7) and compared to the National Emergency Laparotomy Audit (NELA) score with Forest plots used to compare 30-day mortality across CFS and NELA categories. RESULTS: A total of 2246 patients (median age 65 years [IQR 51-75]; female 51%) underwent EmLap (60% for colorectal pathology). A total of 10.6% were frail preoperatively (≥CFS 5). As CFS increased so did 30-day mortality (2.1% CFS1 to 25.3% CFS6 and 7; ꭓ2 78.2, p < 0.001) and median LOS (10 days CFS1 to 20 days CFS6 and 7; p < 0.001). Readmission rates did not differ significantly across CFS. ROC (95% CI) for mortality was 0.71 (0.65-0.77) for CFS and 0.84 (0.78-0.89) for NELA. Addition of CFS to NELA did not increase ROC value. CONCLUSION: This study supports the prognostic role of frailty in the emergency surgical setting, finding increasing frailty to be associated with increased mortality and longer LOS in adults of all ages. Although NELA performed better, CFS remained predictive and has the advantage of being calculated preoperatively to aid decision-making and treatment planning.

Prehabilitation services for people diagnosed with cancer in Scotland - Current practice, barriers and challenges to implementation.

BACKGROUND: Prehabilitation is the practice of enhancing a patient's functional and psychological capacity before treatment commences. It is of interest in the cancer context because of the impact of treatments on quality of life and cancer survivorship. This work aims to document current practice, barriers and challenges to implementing prehabilitation to inform the development of a national framework. METHODS: A mixed-methods approach was applied: an on-line survey was sent to stakeholders in cancer care across Scotland, supplemented by in-depth interviews. Key domains explored were the perceived importance of prehabilitation, availability, delivery and content of services, outcome measures, referral processes and funding. FINDINGS: A total of 295 survey responses were obtained and 11 interviews completed. Perceived importance of prehabilitation was rated highly. There was uncertainty over the definition of prehabilitation and most respondents did not know if local services were available. Where services were described, a range of health professionals were involved, different outcome measures were utilised and frequency of referrals varied. Respondents highlighted short time frames between referral and treatment, concerns about patient engagement, the evidence base for action and funding priorities. Respondents also commented on which context a referral should be made and to whom, and the need for equity of service across the country. CONCLUSIONS: The current work found clear evidence of the perceived importance of prehabilitation in cancer patients. However, issues and key gaps were identified within current services (including issues arising from COVID-19) which must be addressed to enable wide-spread development and implementation of equitable programmes.

Frailty in Older Patients Undergoing Emergency Laparotomy: Results From the UK Observational Emergency Laparotomy and Frailty (ELF) Study.

OBJECTIVE: This study aimed to document the prevalence of frailty in older adults undergoing emergency laparotomy and to explore relationships between frailty and postoperative morbidity and mortality. SUMMARY BACKGROUND DATA: The majority of adults undergoing emergency laparotomy are older adults (≥65 y) that carry the highest mortality. Improved understanding is urgently needed to allow development of targeted interventions. METHODS: An observational multicenter (n=49) UK study was performed (March-June 2017). All older adults undergoing emergency laparotomy were included. Preoperative frailty score was calculated using the progressive Clinical Frailty Score (CFS): 1 (very fit) to 7 (severely frail). Primary outcome measures were the prevalence of frailty (CFS 5-7) and its association to mortality at 90 days postoperative. Secondary outcomes included 30-day mortality and morbidity, length of critical care, and overall hospital stay. RESULTS: A total of 937 older adults underwent emergency laparotomy: frailty was present in 20%. Ninety-day mortality was 19.5%. After age and sex adjustment, the risk of 90-day mortality was directly associated with frailty: CFS 5 adjusted odds ratio (aOR) 3.18 [95% confidence interval (CI), 1.24-8.14] and CFS 6/7 aOR 6·10 (95% CI, 2.26-16.45) compared with CFS 1. Similar associations were found for 30-day mortality. Increasing frailty was also associated with increased risk of complications, length of Intensive Care Unit, and overall hospital stay. CONCLUSIONS: A fifth of older adults undergoing emergency laparotomy are frail. The presence of frailty is associated with greater risks of postoperative mortality and morbidity and is independent of age. Frailty scoring should be integrated into acute surgical assessment practice to aid decision-making and development of novel postoperative strategies.

Healthcare professional preferences in the health and fitness assessment and optimization of older patients facing colorectal cancer surgery.

AIM: There are few age- and fitness-specific, evidence-based guidelines for colorectal cancer surgery. The uptake of different assessment and optimization strategies is variable. The aim of this study was to explore healthcare professional opinion about these issues using a mixed methods design. METHODS: Semi-structured qualitative interviews were undertaken with healthcare professionals from a single UK region involved in the treatment, assessment and optimization of colorectal surgery patients. Interviews were analysed using the framework approach. An online questionnaire survey was subsequently designed and disseminated to UK surgeons to quantitatively assess the importance of interview themes. Descriptive statistics were used to analyse questionnaire data. RESULTS: Thirty-seven healthcare professionals out of 42 approached (response rate 88%) were interviewed across five hospitals in the south Yorkshire region. Three broad themes were developed: attitudes towards treatment of the older patient, methods of assessment of suitability and optimization strategies. The questionnaire was completed by 103 out of an estimated 256 surgeons (estimated response rate 40.2%). There was a difference in opinion regarding the role of major surgery in older patients, particularly when there is coexisting dementia. Assessment was not standardized. Access to optimization strategies was limited, particularly in the emergency setting. CONCLUSION: There is wide variation in the process of assessment and provision of optimization strategies in UK practice. Lack of evidence-based guidelines, cost and time constraints restrict the development of services and pathways. Differences in opinion between surgeons towards patients with frailty or dementia may account for some of the variation in colorectal cancer outcomes.

Barriers and facilitators to deliberate practice using take-home laparoscopic simulators.

BACKGROUND: Several regions in the UK and Ireland have delivered home-based laparoscopic simulation programmes in an attempt to progress surgical trainees' skills through deliberate practice. However, engagement with these programmes has been poor. This study aims to uncover the barriers to engagement with home-based simulation, with a view to developing an improved programme. METHODS: This was a qualitative study using focus groups with key stakeholders including junior surgical trainees, consultants/attendings and simulation faculty. Data were collected across four regions in three countries. Data were audio-recorded, transcribed and a thematic analysis was performed using NVivo software. RESULTS: Sixty-three individuals were interviewed in 12 focus groups (43 trainees, 20 trainers). Trainees cited competing commitments as a barrier to engaging with home-based simulation. They tended to focus on scoring 'points' towards career progression rather than viewing tasks as interesting, or associated with personal development. Their view was that this approach is perpetuated by the training system, which rewards trainees for publications and exams, but not for operative skill. Trainees were unsatisfied with metric feedback and wanted individual feedback from consultants (attendings). Trainees perceived consultants as lacking interest in the programmes and training in general. However, some consultants were unaware of the programmes being delivered and others felt lacking in confidence to deliver the necessary training. CONCLUSIONS: Scheduled simulation sessions which provide trainees with the opportunity for consultant feedback may improve engagement. Tackling the 'point-scoring' culture is more challenging. This could be addressed by modified assessment structures, greater recognition and accountability for trainers, and recognition and funding of simulation strategies including in-house skills sessions.

Lifestyle interventions are feasible in patients with colorectal cancer with potential short-term health benefits: a systematic review.

PURPOSE: Lifestyle interventions have been proposed to improve cancer survivorship in patients with colorectal cancer (CRC), but with treatment pathways becoming increasingly multi-modal and prolonged, opportunities for interventions may be limited. This systematic review assessed the evidence for the feasibility of performing lifestyle interventions in CRC patients and evaluated any short- and long-term health benefits. METHODS: Using PRISMA Guidelines, selected keywords identified randomised controlled studies (RCTs) of lifestyle interventions [smoking, alcohol, physical activity (PA) and diet/excess body weight] in CRC patients. These electronic databases were searched in June 2015: Dynamed, Cochrane Database, OVID MEDLINE, OVID EMBASE, and PEDro. RESULTS: Fourteen RCTs were identified: PA RCTs (n = 10) consisted mainly of telephone-prompted walking or cycling interventions of varied durations, predominately in adjuvant setting; dietary/excess weight interventions RCTs (n = 4) focused on low-fat and/or high-fibre diets within a multi-modal lifestyle intervention. There were no reported RCTs in smoking or alcohol cessation/reduction. PA and/or dietary/excess weight interventions reported variable recruitment rates, but good adherence and retention/follow-up rates, leading to short-term improvements in dietary quality, physical, psychological and quality-of-life parameters. Only one study assessed long-term follow-up, finding significantly improved cancer-specific survival after dietary intervention. CONCLUSIONS: This is the first systematic review on lifestyle interventions in patients with CRC finding these interventions to be feasible with improvements in short-term health. Future work should focus on defining the optimal type of intervention (type, duration, timing and intensity) that not only leads to improved short-term outcomes but also assesses long-term survival.

Heuristics and bias in rectal surgery.

PURPOSE: Deciding to defunction after anterior resection can be difficult, requiring cognitive tools or heuristics. From our previous work, increasing age and risk-taking propensity were identified as heuristic biases for surgeons in Australia and New Zealand (CSSANZ), and inversely proportional to the likelihood of creating defunctioning stomas. We aimed to assess these factors for colorectal surgeons in the British Isles, and identify other potential biases. METHODS: The Association of Coloproctology of Great Britain and Ireland (ACPGBI) was invited to complete an online survey. Questions included demographics, risk-taking propensity, sensitivity to professional criticism, self-perception of anastomotic leak rate and propensity for creating defunctioning stomas. Chi-squared testing was used to assess differences between ACPGBI and CSSANZ respondents. Multiple regression analysis identified independent surgeon predictors of stoma formation. RESULTS: One hundred fifty (19.2%) eligible members of the ACPGBI replied. Demographics between ACPGBI and CSSANZ groups were well-matched. Significantly more ACPGBI surgeons admitted to anastomotic leak in the last year (p < 0.001). ACPGBI surgeon age over 50 (p = 0.02), higher risk-taking propensity across several domains (p = 0.044), self-belief in a lower-than-average anastomotic leak rate (p = 0.02) and belief that the average risk of leak after anterior resection is 8% or lower (p = 0.007) were all independent predictors of less frequent stoma formation. Sensitivity to criticism from colleagues was not a predictor of stoma formation. CONCLUSIONS: Unrecognised surgeon factors including age, everyday risk-taking, self-belief in surgical ability and lower probability bias of anastomotic leak appear to exert an effect on decision-making in rectal surgery.

Analysis of lesion localisation at colonoscopy: outcomes from a multi-centre U.K. study.

BACKGROUND: Colonoscopy is currently the gold standard for detection of colorectal lesions, but may be limited in anatomically localising lesions. This audit aimed to determine the accuracy of colonoscopy lesion localisation, any subsequent changes in surgical management and any potentially influencing factors. METHODS: Patients undergoing colonoscopy prior to elective curative surgery for colorectal lesion/s were included from 8 registered U.K. sites (2012-2014). Three sets of data were recorded: patient factors (age, sex, BMI, screener vs. symptomatic, previous abdominal surgery); colonoscopy factors (caecal intubation, scope guide used, colonoscopist accreditation) and imaging modality. Lesion localisation was standardised with intra-operative location taken as the gold standard. Changes to surgical management were recorded. RESULTS: 364 cases were included; majority of lesions were colonic, solitary, malignant and in symptomatic referrals. 82% patients had their lesion/s correctly located at colonoscopy. Pre-operative CT visualised lesion/s in only 73% of cases with a reduction in screening patients (64 vs. 77%; p = 0.008). 5.2% incorrectly located cases at colonoscopy underwent altered surgical management, including conversion to open. Univariate analysis found colonoscopy accreditation, scope guide use, incomplete colonoscopy and previous abdominal surgery significantly influenced lesion localisation. On multi-variate analysis, caecal intubation and scope guide use remained significant (HR 0.35, 0.20-0.60 95% CI and 0.47; 0.25-0.88, respectively). CONCLUSION: Lesion localisation at colonoscopy is incorrect in 18% of cases leading to potentially significant surgical management alterations. As part of accreditation, colonoscopists need lesion localisation training and awareness of when inaccuracies can occur.

The prevalence of hyperglycaemia and its relationship with mortality, readmissions and length of stay in an older acute surgical population: a multicentre study.

BACKGROUND: The purpose of the study is to examine the prevalence of hyperglycaemia in an older acute surgical population and its effect on clinically relevant outcomes in this setting. METHODS: Using Older Persons Surgical Outcomes Collaboration (OPSOC) multicentre audit data 2014, we examined the prevalence of admission hyperglycaemia, and its effect on 30-day and 90-day mortality, readmission within 30 days and length of acute hospital stay using logistic regression models in consecutive patients, ≥65 years, admitted to five acute surgical units in the UK hospitals in England, Scotland and Wales. Patients were categorised in three groups based on their admission random blood glucose: <7.1, between 7.1 and 11.1 and ≥11.1 mmol/L. RESULTS: A total of 411 patients (77.25±8.14 years) admitted during May and June 2014 were studied. Only 293 patients (71.3%) had glucose levels recorded on admission. The number (%) of patients with a blood glucose <7.1, 7.1-11.1 and ≥11.1 mmol/L were 171 (58.4), 99 (33.8) and 23 (7.8), respectively. On univariate analysis, admission hyperglycaemia was not predictive of any of the outcomes investigated. Although the characteristics of those with no glucose level were not different from the included sample, 30-day mortality was significantly higher in those who had not had their admission glucose level checked (10.2% vs 2.7%), suggesting a potential type II error. CONCLUSION: Despite current guidelines, nearly a third of older people with surgical diagnoses did not have their glucose checked on admission highlighting the challenges in prognostication and evaluation research to improve care of older frail surgical patients.

The lymph node ratio optimises staging in patients with node positive colon cancer with implications for adjuvant chemotherapy.

PURPOSE: The ratio of positive lymph nodes to total retrieved lymph nodes (lymph node ratio, LNR) has been proposed to be the superior prognostic score in colon cancer. This study aimed to validate LNR in a large, multi-centred population, focusing on patients that have undergone adjuvant chemotherapy. METHODS: Analysis of a prospectively collected database (The West of Scotland Colorectal Cancer Managed Clinical Network) with 1,514 patients with colonic cancer identified that had undergone elective curative surgical resection in the 12 hospitals in the West of Scotland from 2000-2004. Variables recorded were as follows: demographics, adjuvant chemotherapy, number of lymph nodes retrieved, lymph node retrieval ≥12, number of positive lymph nodes and LNR. Follow up continued until June 2009. Univariate and multivariate analyses were performed to determine the influence of LNR on overall survival. RESULTS: In 673 patients (44.5%), ≥12 lymph nodes were retrieved. Patients had a poorer long-term prognosis with increasing age, T stage and N stage. Retrieval of <12 lymph nodes and increasing LNR were both found to be significantly associated with poorer long-term survival, but on multivariable analysis, LNR was the only independently significant variable. In patients that had received adjuvant chemotherapy, only patients staged in the second lowest LNR group (0.05-0.19) had a significant improvement in long-term survival. CONCLUSION: Lymph node ratio is the optimal method of assessing lymph node status and highlights the heterogeneity of patients with node positive disease, altering patient stratification with implications for adjuvant chemotherapy.

Collaboration is key: the role of social media in advancing surgical research.

Social media has revolutionized how we design, deliver, and disseminate surgical research for the better. The rise of collaborative research groups has been a major contributor to and beneficiary of social media, leading to increased involvement from clinicians, medical students, healthcare professionals, patients, and industry. Everyone benefits from collaborative research by widening access and participation and delivering more impactful research with increasing validity of results applicable to global populations. Now more than ever, the international surgical community is engaged in the process of surgical research, including the role of interdisciplinary collaboration. Patient groups are also central to the process of collaboration. By delivering increasingly relevant research, and by asking pertinent research questions that patients value, higher-impact research is more likely to directly lead to clinical change. From an academic perspective, hierarchies have flattened, facilitating the inclusion of anyone who is interested in contributing to surgical research to be able to do so. Social media has led to a paradigm shift in how surgical research may be conducted. Diversity of thought in research is improving, and engagement in surgical research is at an all-time high. Collaboration of all stakeholders is key to #SoMe4Surgery success and is the new 'gold standard' of surgical research.

The false dichotomy of surgical futility in the emergency laparotomy setting: scoping review.

BACKGROUND: Futile is defined as 'the fact of having no effect or of achieving nothing'. Futility in medicine has been defined through seven guiding principles, which in the context of emergency surgery, have been relatively unexplored. This scoping review aimed to identify key concepts around surgical futility as it relates to emergency laparotomy. METHODS: Using the Arksey and O'Malley framework, a scoping review was conducted. A search of the Cochrane Library, Google Scholar, MEDLINE, and Embase was performed up until 1 November 2021 to identify literature relevant to the topic of futility in emergency laparotomy. RESULTS: Three cohort studies were included in the analysis. A total of 105 157 patients were included, with 1114 patients reported as futile. All studies were recent (2019 to 2020) and focused on the principle of quantitative futility (assessment of the probability of death after surgery) within a timeline after surgery: two defining futility as death within 48 hours of surgery and one as death within 72 hours. In all cases this was derived from a survival histogram. Predictors of defined futile procedures included age, level of independence prior to admission, surgical pathology, serum creatinine, arterial lactate, and pH. CONCLUSION: There remains a paucity of research defining, exploring, and analysing futile surgery in patients undergoing emergency laparotomy. With limited published work focusing on quantitative futility and the binary outcome of death, research is urgently needed to explore all principles of futility, including the wishes of patients and their families.

Modelling of magnetic microbubbles to evaluate contrast enhanced magnetomotive ultrasound in lymph nodes - a pre-clinical study.

OBJECTIVES: Despite advances in MRI the detection and characterisation of lymph nodes in rectal cancer remains complex, especially when assessing the response to neoadjuvant treatment. An alternative approach is functional imaging, previously shown to aid characterisation of cancer tissues. We report proof of concept of the novel technique Contrast-Enhanced Magneto-Motive Ultrasound (CE-MMUS) to recover information relating to local perfusion and lymphatic drainage, and interrogate tissue mechanical properties through magnetically induced deformations. METHODS: The feasibility of the proposed application was explored using a combination of experimental animal and phantom ultrasound imaging, along with finite element analysis. First, contrast-enhanced ultrasound imaging on one wild type mouse recorded lymphatic drainage of magnetic microbubbles after bolus injection. Second, tissue phantoms were imaged using MMUS to illustrate the force- and elasticity dependence of the magnetomotion. Third, the magnetomechanical interactions of a magnetic microbubble with an elastic solid were simulated using finite element software. RESULTS: Accumulation of magnetic microbubbles in the inguinal lymph node was verified using contrast enhanced ultrasound, with peak enhancement occurring 3.7 s post-injection. The magnetic microbubble gave rise to displacements depending on force, elasticity, and bubble radius, indicating an inverse relation between displacement and the latter two. CONCLUSION: Combining magnetic microbubbles with MMUS could harness the advantages of both techniques, to provide perfusion information, robust lymph node delineation and characterisation based on mechanical properties. ADVANCES IN KNOWLEDGE: (a) Lymphatic drainage of magnetic microbubbles visualised using contrast-enhanced ultrasound imaging and (b) magnetomechanical interactions between such bubbles and surrounding tissue could both contribute to (c) robust detection and characterisation of lymph nodes.