Persistent descending mesocolon as a vital risk factor for anastomotic failure and prolonged operative time for sigmoid colon and rectal cancers.

BACKGROUND: The diagnostic criteria and effect of persistent descending mesocolon (PDM) on sigmoid and rectal cancers (SRCs) remain controversial. This study aims to clarify PDM patients' radiological features and short-term surgical results. METHOD: From January 2020 to December 2021, radiological imaging data from 845 consecutive patients were retrospectively analyzed using multiplanar reconstruction (MRP) and maximum intensity projection (MIP). PDM is defined as the condition wherein the right margin of the descending colon is located medially to the left renal hilum. Propensity score matching (PSM) was used to minimize database bias. The anatomical features and surgical results of PDM patients were compared with those of non-PDM patients. RESULTS: Thirty-two patients with PDM and 813 patients with non-PDM were enrolled into the study who underwent laparoscopic resection. After 1:4 matching, patients were stratified into PDM (n = 27) and non-PDM (n = 105) groups. The lengths from the inferior mesenteric artery (IMA) to the inferior mesenteric vein (1.6 cm vs. 2.5 cm, p = 0.001), IMA to marginal artery arch (2.7 cm vs. 8.4 cm, p = 0.001), and IMA to the colon (3.3 cm vs. 10.2 cm, p = 0.001) were significantly shorter in the PDM group than those in the non-PDM group. The conversion to open surgery (11.1% vs. 0.9%, p = 0.008), operative time (210 min vs. 163 min, p = 0.001), intraoperative blood loss (50 ml vs. 30 ml, p = 0.002), marginal arch injury (14.8% vs. 0.9%, p = 0.006), splenic flexure free (22.2% vs. 3.8%, p = 0.005), Hartmann procedure (18.5% vs. 0.0%, p < 0.001) and anastomosis failure (18.5% vs. 0.9%, p = 0.001) were significantly higher in the PDM group. Moreover, PDM was an independent risk factor for prolonged operative time (OR = 3.205, p = 0.004) and anastomotic failure (OR = 7.601, p = 0.003). CONCLUSION: PDM was an independent risk factor for prolonged operative time and anastomotic failure in SRCs surgery. Preoperative radiological evaluation using MRP and MIP can help surgeons better handle this rare congenital variant.

Arterias sigmoideas: bases para una nueva clasificación / Sigmoid arteries: bases for a new classification

Las arterias sigmoideas son ramas de la arteria mesentérica inferior e irrigan al colon sigmoideo. Se originan del tronco de las arterias sigmoideas. Esta es la descripción más frecuente según los autores consultados. El objetivo fue analizar las variaciones en el origen y distribución de las arterias sigmoideas mediante disección. Se utilizaron 13 preparados cadavéricos formolizados al 10 %. Se disecó la cavidad abdominal para identificar a las arterias sigmoideas. Se evidenció su bifurcación paralela al colon sigmoideo. Se lo delimitó mediante reparos palpables. Patrón I: 4 casos (30,8 %). Variante de la arcada sigmoidea como rama colateral de la arteria mesentérica inferior. Tipo Ia: 1 caso (25 %). Sin asociaciones. Tipo Ib: 1 caso (25 %). Asociada al tronco sigmoideo. Tipo Ic: 2 casos (50 %). Asociada a arterias sigmoideas accesorias. Patrón II: 6 casos (46,2 %). Variante del tronco común entre arteria cólica izquierda y arterias destinadas al colon sigmoideo. Tipo IIa: 3 casos (50 %). Sin asociaciones. Tipo IIb: 2 casos (33,3 %). Asociado al tronco sigmoideo. Tipo IIc: 1 caso (16,7 %). Asociado a arterias sigmoideas accesorias. Patrón III: 3 casos (23 %). Variante clásica. Se definió por la ausencia del tronco común con la arteria cólica izquierda y de la arcada sigmoidea. Tipo IIIa: 2 casos (66,7 %). Un número variable de arterias sigmoideas nacen como ramas colaterales de la arteria mesentérica inferior, sin asociarse al tronco sigmoideo. Tipo IIIb: 1 caso (33,3 %). La arteria cólica izquierda emite como rama colateral la primera arteria sigmoidea y se asocia al tronco sigmoideo. 1. El patrón II es el prevalente en este trabajo (46,2 %). 2. La variante clásica no es la predominante en esta investigación (23 %). 3. La arcada sigmoidea tiene 53,8 % de incidencia.

SUMMARY: The sigmoid arteries are branches of the inferior mesenteric artery and supply the sigmoid colon. They originate from the trunk of the sigmoids. This is the most frequent description according to the consulted authors. The objective is to analyze the variations in the origin and distribution of the sigmoid arteries through dissection. 13 cadaveric preparations formalized at 10 % and instruments were used. The abdominal cavity was dissected to identify the sigmoid arteries. Its bifurcation parallel to the sigmoid colon is evident. It is delimited by palpable repairs. Pattern I: 4 cases (30.8 %). Variant of the sigmoid arcade as a collateral branch of the inferior mesenteric artery. Type Ia: 1 case (25 %). No associations. Type Ib: 1 case (25 %). Associated with the sigmoid trunk. Type Ic: 2 cases (50 %). Associated with accessory sigmoid arteries. Pattern II: 6 cases (46.2 %). Variant of the common trunk between the left colic artery and arteries destined for the sigmoid colon. Type IIa: 3 cases (50 %). No associations. Type IIb: 2 cases (33.3 %). Associated with the sigmoid trunk. Type IIc: 1 case (16.7 %). Associated with accessory sigmoid arteries. Pattern III: 3 cases (23 %). Classic variant. It was defined by the absence of the common trunk with the left colic artery and the sigmoid arcade. Type IIIa: 2 cases (66.7 %). A variable number of sigmoid arteries arise as collateral branches of the inferior mesenteric artery, without being associated with the sigmoid trunk. Type IIIb: 1 case (33.3 %). The left colic artery gives off the first sigmoid artery as a collateral branch and is associated with the sigmoid trunk. 1. Pattern II is the most prevalent in this study (46.2 %). 2. The classic variant is not the predominant one in this research (23 %). 3. The sigmoid arcade has a 53.8 % incidence.

Real-time vascular anatomical image navigation for laparoscopic surgery: experimental study.

BACKGROUND: Recognition of the inferior mesenteric artery (IMA) during colorectal cancer surgery is crucial to avoid intraoperative hemorrhage and define the appropriate lymph node dissection line. This retrospective feasibility study aimed to develop an IMA anatomical recognition model for laparoscopic colorectal resection using deep learning, and to evaluate its recognition accuracy and real-time performance. METHODS: A complete multi-institutional surgical video database, LapSig300 was used for this study. Intraoperative videos of 60 patients who underwent laparoscopic sigmoid colon resection or high anterior resection were randomly extracted from the database and included. Deep learning-based semantic segmentation accuracy and real-time performance of the developed IMA recognition model were evaluated using Dice similarity coefficient (DSC) and frames per second (FPS), respectively. RESULTS: In a fivefold cross-validation conducted using 1200 annotated images for the IMA semantic segmentation task, the mean DSC value was 0.798 (± 0.0161 SD) and the maximum DSC was 0.816. The proposed deep learning model operated at a speed of over 12 FPS. CONCLUSION: To the best of our knowledge, this is the first study to evaluate the feasibility of real-time vascular anatomical navigation during laparoscopic colorectal surgery using a deep learning-based semantic segmentation approach. This experimental study was conducted to confirm the feasibility of our model; therefore, its safety and usefulness were not verified in clinical practice. However, the proposed deep learning model demonstrated a relatively high accuracy in recognizing IMA in intraoperative images. The proposed approach has potential application in image navigation systems for unfixed soft tissues and organs during various laparoscopic surgeries.

How to do: superior rectal artery sparing anterior resection for sigmoid colon cancer - surgical option for vasculopathic patients.

Superior rectal artery sparing oncological anterior resection in vasculopathic patients.

[Reasonable Surgery for Sigmoid Colon Cancer with Asymptomatic Celiac Artery Stenosis and Superior Mesenteric Artery Stenosis-A Case Report].

A 79-year-old woman was diagnosed with cT2N0M0, cStage Ⅰ sigmoid colon cancer. Preoperative staging computed tomography(CT)incidentally revealed severe stenosis of the celiac and superior mesenteric arteries. A collateral blood channel communicating between the inferior mesenteric artery and the celiac artery region was well developed. Therefore, a sigmoidectomy with D1 lymph node dissection was performed to preserve this collateral blood channel as a surgery for sigmoid colon cancer. There are few reports on surgical procedures for patients with simultaneous stenosis of multiple major abdominal arteries. In addition, there are no consensus about the optimal surgical procedure and extent of lymph node dissection for colorectal cancer with well-developed collateral vessels that should be preserved. Preoperative three-dimensional CT angiography(3D-CTA)and intraoperative blood-flow assessment using Indocyanine Green help risk management of multi- organ ischemia due to misidentification and injury of collateral arteries. It is important to keep oncological validity as well as risk management. We report a case of sigmoid colon cancer with asymptomatic stenosis of the celiac and superior mesenteric arteries.

[A Resected Case of the Sigmoid Colon Cancer after the Endovascular Aneurysm Repair in Which Intraoperative Indocyanine Green Fluorescence Method Was Useful for Evaluating the Blood Flow in the Colon].

A man in his 70s underwent an endovascular aneurysm repair(EVAR)for abdominal aortic aneurysm. Blood test revealed an anemia and an increased tumor marker. Enhanced computed tomography revealed the wall thickening in the sigmoid colon and the Type Ⅱ endoleak after EVAR. Colonoscopy showed the wall thickening in the sigmoid colon, and biopsy indicated a diagnosis of adenocarcinoma. We performed open sigmoid colectomy with D3 lymph node dissection and ileostomy. We performed intraoperative indocyanine green (ICG) fluorescence method for evaluating the blood flow in the colon before the high ligation of the inferior mesenteric artery and the creation of the anastomosis, and perfusion of the colon was visualized. He was discharged postoperative day 14, and was performed closure of ileostomy 5 months later. Intraoperative ICG fluorescence method was safety and useful for evaluating the blood flow in the colon.

Preservation of the Arterial Arc Formed by Left Colic Artery, Proximal Inferior Mesenteric Artery, and the First Branch of Sigmoid Arteries in Anus Saving Treatment of Low Rectal Cancer.

BACKGROUND: Low anterior, ultralow anterior, and intersphincteric resection are conventional, elective anus-sparing techniques for low rectal cancer, and good prognosis depends on a good blood supply and tension-free anastomosis. AIM: The goal is to assess the effect of preserving the arc formed by the left colic and proximal inferior mesenteric arteries (IMAs), and first branch of the sigmoid arteries on the anastomotic blood supply, tension, and leakage rate in anus-sparing surgery for low rectal cancer. METHOD: From 2011 to 2020, a patient with low rectal cancer resection was distributed into the ligation group (42 cases with inferior mesenteric artery ligation) and the preservation group (61 cases with preservation of the left colic and proximal IMAs and first branch of the sigmoid artery). RESULTS: We evaluated patient characteristics, operative results, morbidity, and postoperative follow-up results. There were comparable outcomes between ligation and preservation groups in relations to the number of patients in each operative procedure, duration of surgery, operative blood loss, postoperative hospital stay, and the number of patients with protective stoma (P >.05). In postoperative morbidity, there were similar outcomes between ligation and preservation groups in terms of anastomotic subclinical dehiscence, bleeding and stricture, and urinary retention (P >.05). There were significant differences in anastomotic leakage and intra-abdominal abscess (P < .05). CONCLUSION: Preservation of the arterial arc formed by left colic artery, proximal IMA, and the first branch of sigmoid arteries with apical lymph node dissection could increase anastomotic blood supply, reduce anastomotic tension, and leakage rate in anus-saving treatment of low rectal cancer.

Near-infrared fluorescence angiography for colorectal surgery is associated with a reduction of anastomotic leak rate.

Decreased blood perfusion at the anastomotic site increases the risk of anastomotic leakage (AL) following colorectal surgery. Indocyanine green near-infrared fluoroangiography (NIRF/ICG) is a technique that allows for the assessment of intestinal perfusion before and after the formation of an anastomosis. We aimed to compare the rate of AL after colorectal surgery conducted with NIRF/ICG assessing vascular anastomotic perfusion and without this support. The data of patients who underwent colorectal surgery from November 2014 to February 2019 were reviewed retrospectively. Left-sided hemicolectomy, sigmoid resection, and anterior rectal resection were included. Emergency resections were excluded. Procedures conducted with NIRF/ICG and without NIRF/ICG (no-NIRF/ICG) support were compared using Fisher's and Mann-Whitney U test. Overall, 196 procedures were included, 98 were carried out with no-NIRF/ICG and 98 with NIRF/ICG. Patients' clinical and intraoperative characteristics were similar in the two groups. In the NIRF/ICG, fluorescence was detected in 100% of the cases; following NIRF/ICG the planned site of transection was changed in eight cases, whereas in one case the anastomosis was re-performed. Overall, six patients (3%) developed an AL, 0% in the NIRF/ICG and 6% (n = 6) in the no-NIRF/ICG group (p = 0.029). Median hospital length of stay was shorter in the NIRF/ICG group [6 days (IQR 6-7) vs. 7 days (IQR 6-9), p < 0.001]. The results of this study suggest that the use of the NIRF/ICG was safe for colorectal surgery and decreases the risk of anastomotic leak. A randomized trial is required to confirm these preliminary data.

Intestinal ultrasound for monitoring therapeutic response in patients with ulcerative colitis: results from the TRUST&UC study.

OBJECTIVE: Prospective evaluation of intestinal ultrasound (IUS) for disease monitoring of patients with ulcerative colitis (UC) in routine medical practice. DESIGN: TRansabdominal Ultrasonography of the bowel in Subjects with IBD To monitor disease activity with UC (TRUST&UC) was a prospective, observational study at 42 German inflammatory bowel disease-specialised centres representing different care levels. Patients with a diagnosis of a proctosigmoiditis, left-sided colitis or pancolitis currently in clinical relapse (defined as Short Clinical Colitis Activity Index ≥5) were enrolled consecutively. Disease activity and vascularisation within the affected bowel wall areas were assessed by duplex/Colour Doppler ultrasonography. RESULTS: At baseline, 88.5% (n=224) of the patients had an increased bowel wall thickness (BWT) in the descending or sigmoid colon. Even within the first 2 weeks of the study, the percentage of patients with an increased BWT in the sigmoid or descending colon decreased significantly (sigmoid colon 89.3%-38.6%; descending colon 83.0%-42.9%; p<0.001 each) and remained low at week 6 and 12 (sigmoid colon 35.4% and 32.0%; descending colon 43.4% and 37.6%; p<0.001 each). Normalisation of BWT and clinical response after 12 weeks of treatment showed a high correlation (90.5% of patients with normalised BWT had symptomatic response vs 9.5% without symptomatic response; p<0.001). CONCLUSIONS: IUS may be preferred in general practice in a point-of-care setting for monitoring the disease course and for assessing short-term treatment response. Our findings give rise to the assumption that monitoring BWT alone has the potential to predict the therapeutic response, which has to be verified in future studies.

The sigmoidea ima artery: A player in colonic ischemia?

INTRODUCTION: The sigmoidea ima artery is defined as the lowest sigmoid artery, which forms the distal end of the marginal artery by linking with the superior rectal artery. It supplies the rectosigmoid junction, which is a critical area for ischemia. The aim of the present study was to delineate the area supplied by the inferior mesenteric artery with special consideration of the sigmoidea ima artery. MATERIALS AND METHODS: The inferior mesenteric artery was dissected from its origin to the bifurcation of the superior rectal artery in 30 cadavers (15 male, 15 female). Vessel length and distance to the promontory were measured for each branch. RESULTS: There were two manifestations of the sigmoidea ima artery, irrespective of the branching pattern of the inferior mesenteric artery. It originated below the promontory in 25 cases (83.3%) and above it in three (10%). It did not derive from the superior rectal artery in two cases (6.7%). In these 16.7%, the marginal artery was absent near the rectosigmoid junction. CONCLUSIONS: We suggest the terms "arteria sigmoidea ima pelvina" and "arteria sigmoidea ima abdominalis" for the two variants. The terms "arteria marginalis pelvina" and "arteria marginalis abdominalis" could be applied in clinical practice. An abdominal marginal artery could be considered a risk factor for colonic ischemia in colorectal resections and abdominal aortic aneurysm repair. Both variants should be considered when pre- and intra-operative perfusion measurements are interpreted.

Cold Renal Perfusion During Simulation of Juxtarenal Aortic Aneurysm Repair Reduces Systemic Oxidative Stress and Sigmoid Damage in Rats.

OBJECTIVES: Juxtarenal aortic surgery induces renal ischaemia reperfusion, which contributes to systemic inflammatory tissue injury and remote organ damage. Renal cooling during suprarenal cross clamping has been shown to reduce renal damage. It is hypothesised that renal cooling during suprarenal cross clamping also has systemic effects and could decrease damage to other organs, like the sigmoid colon. METHODS: Open juxtarenal aortic aneurysm repair was simulated in 28 male Wistar rats with suprarenal cross clamping for 45 min, followed by 20 min of infrarenal aortic clamping. Four groups were created: sham, no, warm (37 °C saline), and cold (4 °C saline) renal perfusion during suprarenal cross clamping. Primary outcomes were renal damage and sigmoid damage. To assess renal damage, procedure completion serum creatinine rises were measured. Peri-operative microcirculatory flow ratios were determined in the sigmoid using laser Doppler flux. Semi-quantitative immunofluorescence microscopy was used to measure alterations in systemic inflammation parameters, including reactive oxygen species (ROS) production in circulating leukocytes and leukocyte infiltration in the sigmoid. Sigmoid damage was assessed using digestive enzyme (intestinal fatty acid binding protein - I-FABP) leakage, a marker of intestinal integrity. RESULTS: Suprarenal cross clamping caused deterioration of all systemic parameters. Only cold renal perfusion protected against serum creatinine rise: 0.45 mg/dL without renal perfusion, 0.33 mg/dL, and 0.14 mg/dL (p = .009) with warm and cold perfusion, respectively. Microcirculation in the sigmoid was attenuated with warm (p = .002) and cold renal perfusion (p = .002). A smaller increase of ROS production (p = .034) was seen only after cold perfusion, while leukocyte infiltration in the sigmoid colon decreased after warm (p = .006) and cold perfusion (p = .018). Finally, digestive enzyme leakage increased more without (1.5AU) than with warm (1.3AU; p = .007) and cold renal perfusion (1.2AU; p = .002). CONCLUSIONS: Renal ischaemia/reperfusion injury after suprarenal cross clamping decreased microcirculatory flow, increased systemic ROS production, leukocyte infiltration, and I-FABP leakage in the sigmoid colon. Cold renal perfusion was superior to warm perfusion and reduced renal damage and had beneficial systemic effects, reducing sigmoid damage in this experimental study.

Assessment of a Staging System for Sigmoid Colon Cancer Based on Tumor Deposits and Extramural Venous Invasion on Computed Tomography.

Importance: Preoperative TNM stratification of colon cancer on computed tomography (CT) does not identify patients who are at high risk of recurrence that could be selected for preoperative treatment. Objective: To evaluate the utility of CT findings for prognosis of sigmoid colon cancer. Design, Setting, and Participants: This prognostic study used retrospective data from patients who underwent bowel resection for sigmoid colon cancer between January 1, 2006, and January 1, 2015, at a tertiary care center receiving international and national referrals for colorectal cancer. Statistical analysis was performed in April 2019. Main Outcomes and Measures: Cox proportional hazards regression analysis was performed to investigate CT findings associated with disease recurrence. Kaplan-Meier survival plots were calculated for disease-free survival using CT staging systems. Results: Of the 414 patients who had sigmoid colon cancer (248 [60.0%] men; mean [SD] age, 66.1 [12.7] years), with median follow-up of 61 months (interquartile range, 40-87 months), 122 patients (29.5%) developed disease recurrence. On multivariate analysis, nodal disease was not associated with disease recurrence; only tumor deposits (hazard ratio [HR], 1.90; 95% CI, 1.21-2.98; P = .006) and extramural venous invasion (HR, 1.97; 95% CI, 1.26-3.06; P = .003) on CT were associated with disease recurrence. Significant differences in disease-free survival were found using CT-T3 substage classification (HR, 1.88; 95% CI, 1.32-2.68) but not CT-TNM (HR, 1.55; 95% CI, 0.94-2.55). The presence of tumor deposits or extramural venous invasion on CT (HR, 2.45; 95% CI, 1.68-3.56) had the strongest association with poor outcome. Conclusions and Relevance: In this study, T3 substaging and detection of tumor deposits or extramural venous invasion on preoperative CT scans of sigmoid colon cancer were prognostic factors for disease-free survival, whereas TNM and nodal staging on CT had no prognostic value. T3 substaging and detection of tumor deposits or extramural venous invasion of sigmoid colon cancer was superior to TNM on CT and could be used to preoperatively identify patients at high risk of recurrence.

Laparoscopic surgery for colorectal cancer with persistent descending mesocolon.

BACKGROUND: Persistent descending mesocolon (PDM) is caused by the absence of fusion of the descending colon to the retroperitoneum. We herein report two colorectal cancer cases with PDM that were treated with laparoscopic surgery. CASE PRESENTATION: Case 1: a 50-year-old man with sigmoid colon cancer and synchronous liver metastasis. After neoadjuvant chemotherapy, he underwent laparoscopic sigmoidectomy with lymph node dissection cutting the root of the inferior mesenteric artery (IMA) and synchronous liver resection. He experienced postoperative stenosis of the reconstructed colon possibly due to an impaired arterial blood flow in the reconstructed colon. Case 2: a 77-year-old man with rectal cancer. Laparoscopic low anterior resection preserving the left colic artery (LCA) was performed. Intraoperative infrared ray (IR) imaging using indocyanine green (ICG) showed good blood flow of the reconstructed colon. He had no postoperative complications. In cases of PDM, the mesentery of the descending and sigmoid colon containing the LCA is often shortened, and the marginal artery of the reconstructed colon is located close to the root of the LCA. Lymph node dissection accompanied by cutting the LCA carries a risk of marginal artery injury. Therefore, we recommend lymph node dissection preserving the LCA in colorectal cancer patients with PDM in order to maintain the blood flow of the reconstructed colon. If the IMA and LCA absolutely need to be cut for complete lymph node dissection, the marginal artery should be clearly identified and preserved. In addition, intraoperative IR imaging is extremely useful for evaluating colonic perfusion and reducing the risk of anastomotic complications. CONCLUSION: In colorectal cancer surgery in patients with PDM, surgeons should be aware of these tips for maintaining the blood flow of the reconstructed colon and thereby avoid postoperative complications caused by an impaired blood flow.

Hypovolemic shock after pelvic radiotherapy. A rare combination leading to a devastating complication.

BACKGROUND: Radiotherapy currently plays a key role in pelvic malignancies' management. Excellent outcomes have been reported on its association with chemotherapy for the treatment of the anal carcinoma. Despite that, the combined use of chemo- and radiotherapy and the high doses administered seem to be strongly associated with early and late onset side effects. METHODS: We reported a case of a 72 years old woman, affected by anal squamous cell carcinoma. She underwent chemotherapy, and then radiotherapy, with good results. RESULTS: During a regular MR control, the patient developed anaphylactic reaction to Gadolinium, and after that a rectosigmoid ischemia with total necrosis of the posterior rectal wall was diagnosed and surgically treated with Hartmann procedure. CONCLUSION: In our case we faced with the rapid and severe degeneration of pelvic anatomy determined by the sum of vascular alterations following hypovolemic shock and pelvic tissues alteration after radiotherapy. It seems essential not to underestimate the exponential outcome of a similar unusual combination of events. KEY WORDS: Anal carcinoma, Hypovolemic shock, Pelvic radiotherapy, Rectal necrosis.

Imbalanced mucosal microcirculation in the remission stage of ulcerative colitis using probe-based confocal laser endomicroscopy.

BACKGROUND: Microcirculatory disturbance is an important factor in the pathogenesis of Inflammatory Bowel Disease (IBD) but there have been few studies in this field. Confocal Laser Endomicroscopy (CLE) has been used over the last 10 years and has made it possible to explore the changes in microcirculation of the colonic mucosa. METHODS: We retrospectively selected patients who underwent probe-based Confocal Laser Endomicroscopy (pCLE) between 2014 and 2016. There were 7 patients with ulcerative colitis (UC) in clinical remission and 7 healthy subjects included in this study; all the UC patients' medical data were reviewed. For each patient, three segments of the colon were examined using pCLE including the ascending, transverse/descending and sigmoid colon. In each segment, the representative pCLE images of the three sites were selected for analysis. Four indicators, including Mean Vessel Diameter (MVD), Diameter Standard Deviation (DSD), Functional Capillary Density-long (FCDL) and Functional Capillary Density-area (FCDA), were measured with a specially designed detection software algorithm. The four indicators were compared between UC patients and healthy subjects. According to the different blood flow patterns, three types of distribution were established: the Around (A), Cobweb (C) and Deficiency (D) type. The relationships between the recurrence and blood flow patterns of UC patients were analyzed. RESULTS: MVD, DSD, FCDL and FCDA were 10.62 ± 0.56 µm, 2.23 ± 0.26, 0.030 ± 0.019 µm and 0.289 ± 0.030 for the healthy subjects and 11.06 ± 1.10 µm, 2.68 ± 0.29, 0.026 ± 0.005 µm and 0.272 ± 0.034 for the UC patients, respectively. Compared with healthy subjects, DSD was significantly increased and FCDA was significantly decreased (P < 0.01 for both). There was no difference in MVD and FCDL between UC patients and healthy subjects. The type A and type C blood flows were observed in healthy subjects (66.67 and 33.33%, respectively) while type C appears more in UC patients (71.3%) and type D blood flow could only be found in UC patients (14.29%) P < 0.01. UC patients who showed Type D blood flow had a shorter recurrence interval. CONCLUSIONS: Some local mucosal capillary density in UC patients was decreased, particularly in the inflammation-affected segment. The three mucosal blood flow patterns can be used as an indicator of mucosal healing.