Diagnostic value of one-stop CT energy spectrum and perfusion for angiogenesis in colon and rectum cancer.

OBJECTIVE: Evaluation of the predictive value of one-stop energy spectrum and perfusion CT parameters for microvessel density (MVD) in colorectal cancer cancer foci. METHODS: Clinical and CT data of 82 patients with colorectal cancer confirmed by preoperative colonoscopy or surgical pathology in our hospital from September 2019 to November 2022 were collected and analyzed retrospectively. Energy spectrum CT images were measured using the Protocols general module of the GSI Viewer software of the GE AW 4.7 post-processing workstation to measure the CT values of the arterial and venous phase lesions and the neighboring normal intestinal wall in a single energy range of 40 kev∼140 kev, and the slopes of the energy spectrum curves (λ) were calculated between 40 kev-90 kev; Iodine concentration (IC), Water concentration (WC), Effective-Z (Eff-Z) and Normalized iodine concentration (NIC) were measured by placing a region of interest (ROI) on the iodine concentration map and water concentration map at the lesion and adjacent to the normal intestinal wall.Perfusion CT images were scanned continuously and dynamically using GSI Perfusion software and analyzed by applying CT Perfusion 4.0 software.Blood volume (BV), blood flow (BF), surface permeability (PS), time to peak (TTP), and mean transit time (MTT) were measured respectively in the lesion and adjacent normal colorectal wall. Based on the pathological findings, the tumors were divided into a low MVD group (MVD < 35/field of view, n = 52 cases) and a high MVD group (MVD ≥ 35/field of view, n = 30 cases) using a median of 35/field of view as the MVD grouping criterion. The collected data were statistically analyzed, the subjects' operating characteristic curve (ROC) was plotted, and the area under curve (AUC), sensitivity, specificity, and Yoden index were calculated for the predicted efficacy of each parameter of the energy spectrum and perfusion CT and the combined parameters. RESULTS: The CT values, IC, NIC, λ, Eff-Z of 40kev∼140kev single energy in the arterial and venous phase of colorectal cancer in the high MVD group were higher than those in the low MVD group, and the differences were all statistically significant (p < 0.05). The AUC of each single-energy CT value in the arterial phase from 40 kev to 120 kev for determining the high or low MVD of colorectal cancer was greater than 0.8, indicating that arterial stage has a good predictive value for high or low MVD in colorectal cancer; AUC for arterial IC, NIC and IC + NIC were all greater than 0.9, indicating that in arterial colorectal cancer, both single and combined parameters of spectral CT are highly effective in predicting the level of MVD. The AUC of 40 kev to 90 kev single-energy CT values in the intravenous phase was greater than 0.9, and its diagnostic efficacy was more representative; The AUC of IC and NIC in venous stage were greater than 0.8, which indicating that the IC and NIC energy spectrum parameters in venous stage colorectal cancer have a very good predictive value for the difference between high and low MVDs, with the greatest diagnostic efficacy in IC.The values of BV and BF in the high MVD group were higher than those in the low MVD group, and the differences were statistically significant (P < 0.05), and the AUC of BF, BV, and BV + BF were 0.991, 0.733, and 0.997, respectively, with the highest diagnostic efficacy for determining the level of MVD in colorectal cancer by BV + BF. CONCLUSION: One-stop CT energy spectrum and perfusion imaging technology can accurately reflect the MVD in living tumor tissues, which in turn reflects the tumor angiogenesis, and to a certain extent helps to determine the malignancy, invasion and metastasis of living colorectal cancer tumor tissues based on CT energy spectrum and perfusion parameters.

Laparoscopic D3 lymph node dissection with left colic artery and first sigmoid artery preservation in rectal cancer.

BACKGROUND: D3 lymph node dissection with left colic artery (LCA) preservation in rectal cancer surgery seems to have little effect on reducing postoperative anastomotic leakage. So we first propose D3 lymph node dissection with LCA and first sigmoid artery (SA) preservation. This novel procedure deserves further study. METHODS: Rectal cancer patients who underwent laparoscopic D3 lymph node dissection with LCA preservation or with LCA and first SA preservation between January 2017 and January 2020 were retrospectively assessed. The patients were categorized into two groups: the preservation of the LCA group and the preservation of the LCA and first SA group. A 1:1 propensity score-matched analysis was performed to decrease confounding. RESULTS: Propensity score matching yielded 56 patients in each group from the eligible patients. The rate of postoperative anastomotic leakage in the preservation of the LCA and first SA group was significantly lower than that in the LCA preservation group (7.1% vs. 0%, P=0.040). No significant differences were observed in operation time, length of hospital stay, estimated blood loss, length of distal margin, lymph node retrieval, apical lymph node retrieval, and complications. A survival analysis showed patients' 3-year disease-free survival (DFS) rates of group 1 and group 2 were 81.8% and 83.5% (P=0.595), respectively. CONCLUSION: D3 lymph node dissection with LCA and first SA preservation for rectal cancer may help reduce the incidence of anastomotic leakage without compromising oncological outcomes compare with D3 lymph node dissection with LCA preservation alone.

MRI-detected extramural vascular invasion potentiates the risk for pathological metastasis to the lateral lymph nodes in rectal cancer.

PURPOSE: Multidisciplinary treatment for locally advanced rectal cancer requires an accurate assessment of the risk of metastasis to the lateral lymph nodes (LNs). We herein aimed to stratify the risk of pathological metastasis to lateral LNs based on the preoperatively detected malignant features. METHODS: All patients with rectal cancer who underwent surgery from January 2016 to July 2020 were identified. We recorded the TNM factors; perirectal and lateral LN sizes; and MRI findings, including mesorectal fascia involvement, extramural vascular invasion (EMVI), tumor site, and tumor distance from the anal verge. RESULTS: 101 patients underwent rectal resection with lateral lymph node dissection, of whom 16 (15.8%) exhibited pathological metastases to the lateral LNs. Univariate analyses demonstrated that lateral LN metastasis was significantly correlated with mrEMVI positivity (p = 0.0023) and a baseline lateral LN short-axis length of ≥ 5 mm (p < 0.0001). These significant associations were confirmed by a multivariate analysis (p = 0.0254 and 0.0027, respectively). The lateral LN metastasis rate was as high as 44% in cases bearing both risk factors, compared to 0% in cases lacking both risk factors. CONCLUSION: The results elucidated in this study may contribute to risk stratification, which can be used when determining the indications for lateral lymph node dissection.

[Controversy and consideration of high and low ligation of inferior mesenteric artery in radical resection of rectal cancer].

Radical resection is one of the most important treatment for rectal cancer, which requires not only removal of adequate bowel and mesorectum around the tumor, but also thorough lymphadenectomy. Besides, postoperative complications are surgeons' concerns as well. According to different ways to manage inferior mesenteric artery, procedures could be divided into two groups: inferior mesenteric artery (IMA) high ligation and low ligation, which lead to various outcomes of the extent of lymph nodes dissection, survival, preservation of intestinal blood supply, incidence of anastomotic leakage, and postoperative functions including defecation function, urinary function and sexual function. Author believes that for those patients with clinical stage T1, low ligation and D2 lymph nodes dissection could be considered. However, for patients with locally advanced carcinomas (clinical stage T2+or N+), especially suspicious metastasis of lymph nodes around IMA root, high ligation and D3 lymph node dissection is suggested to ensure en bloc resection. As for those patients with high risks for compromised intestinal blood supply, preservation of left colic artery plus D3 lymph nodes dissection might be a feasible way. Intraoperative indocyanine green fluorescent imaging might play a role in quality control of lymphadenectomy.

Novel nomogram with microvascular density in the surgical margins can accurately predict the risk for anastomotic leakage after anterior resection for rectal cancer.

BACKGROUND: Anastomotic leakage (AL) is a serious complication after anterior resection. The purpose of this study was to determine the role of microvascular density (MVD) in AL and to develop a nomogram to accurately predict AL. METHODS: This study retrospectively enrolled 477 consecutive patients who underwent anterior resection for rectal cancer from January 2011 to January 2019. Tissue samples of the resection margins were assessed for MVD. Univariate and multivariate regression analyses were used to identify the risk factors for AL. RESULTS: The incidence of clinical AL was 6.7%. MVD in the distal margin was associated with AL (P < .001). Univariate and multivariate regression analysis identified the following variables as independent risk factors for AL: preoperative albumin ≤35 g/L (odds ratio [OR] = 2.511), neoadjuvant treatment (OR = 3.560), location of tumor ≤7 cm (OR = 3.381), blood loss ≥100 mL (OR = 2.717), and MVD in the distal margin ≤20 (OR = 4.265). Then, a nomogram including these predictors was developed. The nomogram showed good discrimination (AUC = 0.816) and calibration (concordance index = 0.816). The decision curve analysis demonstrated that the nomogram was clinically useful. CONCLUSIONS: MVD in the distal margin is closely associated with AL. The nomogram can be used for individualized prediction of AL after anterior resection for patients with rectal cancer.

The impact of indocyanine-green fluorescence angiogram on colorectal resection.

BACKGROUND: Perfusion plays an important role in anastomotic healing. Indocyanine-green fluorescence angiogram allows objective bowel perfusion assessment. This study aimed to investigate the impact of perfusion assessment on intraoperative decision during left-sided colorectal resections. METHOD: This was a prospective, single-centre, observational study recruiting patients with left-sided colorectal resections. Perfusion of bowel segment was assessed with ICG fluorescence angiogram prior to resection and anastomosis intra-operatively. The planned transection site and the actual transection site after perfusion assessment were compared. The decision for diversion stoma was also evaluated. RESULTS: 110 patients with cancer of the sigmoid colon (29.1%) and rectum (70.9%) were recruited. Total mesorectal excision was performed in 51.8% of patients. The transection site was revised in 34.5% of cases: 30.9% more proximally and 3.6% more distally. The median distance between the intended and actual transection sites was 2 cm (range 1-17 cm). A proximal revision in the transection site was more likely seen in rectal cancers (p = 0.036, OR 3.58, 95% CI 1.09-11.78) and relatively under-perfused left colon (p = 0.036, OR 1.01, 95% CI 1.01-1.02). Three (2.7%) patients were spared from a diversion stoma. The overall anastomotic leakage rate was 5.5%. CONCLUSION: ICG fluorescence angiogram altered operative decisions in a significant proportion of cases. The impact on transection site was more pronounced in patients with rectal cancers and those with relatively under-perfused colon.

Rectal perfusion parameters normalised to tumour-free rectal wall can predict response to neoadjuvant chemoradiotherapy.

AIMS: To evaluate absolute changes in quantitative and semi-quantitative perfusion parameters using a newer approach of comparing these parameters with tumour-free normal rectal wall (i.e., relative/normalised change) in predicting complete pathological response to chemoradiotherapy. MATERIALS AND METHODS: Perfusion parameters measured before and after treatment of 10 patients with histopathologically proven rectal cancer that showed complete treatment response (Group 1) were compared with 10 patients with residual tumour on histopathology following treatment (Group 2). Quantitative perfusion MRI parameters (Ktrans: volume transfer coefficient reflecting vascular permeability, Kep: flux rate constant, Ve: extracellular volume ratio reflecting vascular permeability, integral of area under the curve (IAUC); Toft model) were quantified by manually delineating a region of interest in the upper, mid and lower third of the tumour (1 cm2), in addition similar parameters were obtained from the normal rectal wall at least 1 cm away from the potential resection margin, absolute as well as relative perfusion values normalised to that of the normal rectal wall were evaluated. The differences in absolute and normalised qualitative parameters were compared within each group using paired t-tests and between each group using analysis of variance (ANOVA). RESULTS: Wash-in, wash-out, positive enhancement integral (PEI), Ktrans, IAUC in the complete pathological responders when compared to the adjacent normal rectal wall showed ratios approaching 1, suggesting that rectal perfusion is similar to the adjacent normal rectal wall in complete pathological responders. The difference in the normalised values in the responders and non-responders was statistically significant. CONCLUSION: Perfusion parameters can be used in predicting response to treatment, when normalised to the adjacent normal rectal wall.

High ligation of the inferior mesenteric artery during sigmoid colon and rectal cancer surgery increases the risk of anastomotic leakage: a meta-analysis.

BACKGROUND: The ideal level of ligation of the inferior mesenteric artery (IMA) during curative resection of sigmoid colon and rectal cancer is still controversial. The aim of this meta-analysis was to examine the impact of high ligation and low ligation of the IMA on anastomotic leakage, overall morbidity, postoperative mortality, and oncological outcomes in patients undergoing surgery for sigmoid colon and rectal cancer. METHODS: PubMed, EMBASE, Web of Science, and BioMed Central databases were searched to identify relevant articles published from May 1953 to March 2018. A total of 18 articles (14 non-randomized studies and 4 randomized clinical trials) were identified. Review Manager 5.3 software was used for analysis of data. The pooled odds ratio (OR) and weighted mean difference (WMD), with 95% CI, were calculated using either the fixed effects model or random effects model. RESULTS: Of the 5917 patients included in this meta-analysis, 3652 patients underwent low ligation of the IMA and 2265 patients underwent high ligation of the IMA. Anastomotic leakage rate was 9.8% in high ligation patients vs. 7.0% in low ligation patients; the risk of anastomotic leakage was significantly higher in high ligation patients (OR = 1.33; 95% CI 1.10-1.62; P = 0.004). What is more, overall morbidity was also significantly higher in high ligation patients (OR = 1.39; 95% CI, 1.05-1.68; P = 0.05). Postoperative mortality, number of harvested lymph nodes, overall recurrence rate, and 5-year survival rate did not differ significantly between the two groups. CONCLUSION: Low ligation of the IMA during curative resection of sigmoid colon and rectal cancer appears to be associated with lower risk of anastomotic leakage and overall morbidity. However, there was no significant advantage of low ligation over high ligation of IMA in terms of postoperative mortality, the number of harvested lymph nodes, overall recurrence rate, or 5-year survival rate.

[Guidelines for the management of malignant colo-rectal polyps (pTis and pT1) treated by endoscopic resection]. / Protocole d'examen d'un polype colorectal pTis/pT1 traité par exérèse endoscopique.

The therapeutic management of malignant colorectal polyp with endoscopic resection is mainly based on specific histopathological criteria. The quality of these criteria is strongly linked to the management of the endoscopic specimen. The French Pathology Society drafted a standardized pathological report with guidelines for the macroscopic management of the endoscopic specimen and explanatory notes for each histopathological criteria. These guidelines are based on the TNM AJCC/UICC classification, 8th edition and the WHO 2010 classification of colorectal tumors, the recommendations of the French Society of Digestive Endoscopy, the synthesis of the literature and on international consensus for prognostic criteria. The pathological report of a malignant colorectal polyp must clearly mention: the histological type and the size of the polyp, the pT stage and the following five prognostic criteria: the value of the resection margins, the level of tumor invasion into the submucosa, the grade of the tumor, the absence or presence of vascular emboli and of tumor budding.

[A Case of Ischemic Colitis Four Months after Laparoscopic Left Hemicolectomy Preserving Superior Rectal Artery].

The case was for a male at the age of 80. We performed laparoscopic left hemicolectomy and D3 lymph node dissection for descending colon cancer. He had a good postoperative prognosis and was discharged on the 14th day after the operation. Later, he was receiving the treatment on an outpatient basis without postoperative adjuvant chemotherapy during the followup period. He visited the hospital for sudden abdominal pain and melena as chief complaint approximately 4 months after the operation. We found prominent edematous wall thickening and increased surrounding fat concentration in the anal side of colon from the anastomosis site with plain abdominal CT scan. We also found that the anal side of colon from the anastomosis site an edematous change broadly in the lower gastrointestinal endoscopy. We conducted conservative treatment with the diagnosis of ischemic colitis at the anal side of colon from the anastomosis site. He was discharged on the 11th day after the hospitalization. Later, we conducted a follow-up examination for him on an outpatient basis. We recognized the symptom improvement approximately 2 months after the onset of the ischemic colitis.

Anatomy of the middle rectal artery: a review of the historical literature.

The middle rectal artery is a very important anatomical structure in rectal cancer surgery. It is the only vessel that penetrates through the proper rectal fascia into the pelvic cavity, and therefore threatens the integrity of total mesorectal excision. Moreover, it is very closely related to the lateral lymphatic drainage root. The definition of the middle rectal artery is ambiguous, and different frequencies, origins, and trajectories have been reported in various papers. The frequency of the middle rectal artery is reported to range from 12 to 97 %. Traditionally, the middle rectal artery is described as an artery that penetrates the pelvic plexus from the lateral side along with the lateral ligament; the frequency of this lateral type of middle rectal artery ranges from 20 to 30 %. However, the reports that describe higher frequency values also consider another type of middle rectal artery, which penetrates the neuro-vascular bundle from the antero-lateral direction; this antero-lateral type of middle rectal artery tends to be a small vessel, and frequently forms a common trunk with the prostatic artery. With advancements in endoscopic surgery, the knowledge of the precise anatomy of this structure is becoming more crucial for optimal rectal cancer surgery.

[A Case of Laparoscopic Low Anterior Dissection for Rectal Carcinoma with Left-Sided Inferior Vena Cava].

A 43-year old-male was admitted to the hospital for the treatment of rectal carcinoma. Preoperative abdominal computed tomography(CT)revealed a left inferior vena cava. There is no report of the patient with left inferior vena cava which focused on an anatomical feature of autonomic nerves. We report a case of rectal cancer patient with left inferior vena cava who underwent autonomic nerve-sparing laparoscopic low anterior resection, and review the relevant literature here.

Non-invasive MR assessment of macroscopic and microscopic vascular abnormalities in the rectal tumour-surrounding mesorectum.

OBJECTIVES: To evaluate the MRI macroscopic and microscopic parameters of mesorectal vasculature in rectal cancer patients. METHODS: Thirteen patients with rectal adenocarcinoma underwent a dynamic contrast-enhanced MRI at 1.5 T using a blood pool agent at the primary staging. Mesorectal macrovascular features, i.e., the number of vascular branches, average diameter and length, were assessed from baseline-subtracted post-contrast images by two independent readers. Mesorectal microvascular function was investigated by means of area under the enhancement-time curve (AUC). Histopathology served as reference standard of the tumour response to CRT. RESULTS: The average vessel branching in the mesorectum around the tumour and normal rectal wall was 8.2 ± 3.8 and 1.7 ± 1.3, respectively (reader1: p = 0.001, reader2: p = 0.002). Similarly, the tumour-surrounding mesorectum displayed circa tenfold elevated AUC (p = 0.01). Interestingly, patients with primary node involvement had a twofold higher number of macrovascular branches compared to those with healthy nodes (reader1: p = 0.005 and reader2: p = 0.03). A similar difference was observed between good and poor responders to CRT, whose tumour-surrounding mesorectum displayed 10.7 ± 3.4 and 5.6 ± 1.5 vessels, respectively (reader1/reader2: p = 0.02). CONCLUSIONS: We showed at baseline MRI of rectal tumours a significantly enhanced macrovascular structure and microvascular function in rectal tumour-surrounding mesorectum, and the association of primary mesorectal macrovascular parameters with node involvement and therapy response. KEY POINTS: • Vascular MRI reveals macrovascular and microvascular abnormalities in the rectal tumour-surrounding mesorectum. • Formation of highly vascular stroma precedes the actual tumour invasion. • High macrovascular parameters are associated with node involvement. • Mesorectal vascular network differs for good and poor responders.

High arterial ligation and risk of anastomotic leakage in anterior resection for rectal cancer in patients with increased cardiovascular risk.

AIM: Controversy still exists as to whether division of the inferior mesenteric artery close to the aorta influences the risk of anastomotic leakage after anterior resection for rectal cancer. This population-based study was carried out to evaluate the independent association between high arterial ligation and anastomotic leakage in patients with increased cardiovascular risk. METHOD: All 2673 cases of registered anterior resection for rectal cancer from 2007 to 2010 were identified from the Swedish Colorectal Cancer Registry and cross-referenced with the Prescribed Drugs Registry, rendering a cohort of all patients with increased cardiovascular risk. Operative charts and registered data were reviewed for 722 patients. The association between high tie and anastomotic leakage, as quantified by ORs and 95% CIs, was evaluated in a logistic regression model, with adjustment for confounding, including assessment of interaction. RESULTS: Symptomatic anastomotic leakage occurred in 12.3% (41/334) of patients in the high tie group and in 10.6% (41/388) in the low tie group. The use of high tie was not independently associated with a higher risk of anastomotic leakage (OR = 1.05; 95% CI: 0.61-1.84). In a post-hoc analysis, patients with a history of manifest cardiovascular disease and American Society of Anesthesiologists (ASA) score III-IV seemed to be at greater risk (OR = 3.66; 95% CI: 1.04-12.85). CONCLUSION: In the present population-based, observational setting, high tie was not independently associated with an increased risk of symptomatic anastomotic leakage after anterior resection for rectal cancer. However, this conclusion may not hold for patients with severe cardiovascular disease.

Extramural venous invasion is a potential imaging predictive biomarker of neoadjuvant treatment in rectal cancer.

BACKGROUND: Extramural venous invasion (EMVI) is a poor prognostic factor in rectal cancer and identified on magnetic resonance imaging (MRI) (mrEMVI). The clinical relevance of improvement in mrEMVI following neoadjuvant therapy is unknown. This study aimed to demonstrate that regression of mrEMVI following neoadjuvant chemoradiotherapy (CRT) results in improved outcomes and mrEMVI can be used as an imaging biomarker. METHODS: Retrospective analysis of prospectively collected data was conducted examining the staging and post-treatment MRIs of patients who had presented with EMVI-positive rectal cancer. All patients had undergone neoadjuvant CRT and curative surgery. Changes in mrEMVI were graded with a new MRI-based TRG scale-mr-vTRG; and related to disease-free survival (DFS). The study fulfilled Reporting Recommendations for Tumour Marker Prognostic Studies criteria for biomarkers. RESULTS: Sixty-two patients were included. Thirty-five patients showed more than 50% fibrosis of mrEMVI (mr-vTRG 1-3); 3-year DFS 87.8% and 9% recurrence. Twenty-seven patients showed less than 50% fibrosis (mr-vTRG 4-5); 3-year DFS 45.8% with 44% recurrence - P<0.0001. On multivariate Cox-regression, only mr-vTRG 4-5 increased risk of disease recurrence - HR=5.748. CONCLUSION: Patients in whom there has been a significant response of EMVI to CRT show improved DFS. Those patients with poor response should be considered for intensive treatment. As an imaging biomarker in rectal cancer, mrEMVI can be used.

Rectal cancer: dynamic contrast-enhanced MRI correlates with lymph node status and epidermal growth factor receptor expression.

PURPOSE: To evaluate correlations between dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and clinicopathologic data as well as immunostaining of the markers of angiogenesis epidermal growth factor receptor (EGFR) and CXC-motif chemokine receptor 4 (CXCR4) in patients with rectal cancer. MATERIALS AND METHODS: Presurgical DCE-MRI was performed in 41 patients according to a standardized protocol. Two quantitative parameters (k21 , A) were derived from a pharmacokinetic two-compartment model, and one semiquantitative parameter (TTP) was assessed. Standardized surgery and histopathologic examinations were performed in all patients. Immunostaining for EGFR and CXCR4 was performed and evaluated with a standardized scoring system. RESULTS: DCE-MRI parameter A correlated significantly with the N category (P = 0.048) and k21 with the occurrence of synchronous and metachronous distant metastases (P = 0.029). A trend was shown toward a correlation between k21 and EGFR expression (P = 0.107). A significant correlation was found between DCE-MRI parameter TTP and the expression of EGFR (P = 0.044). DCE-MRI data did not correlate with CXCR4 expression. CONCLUSION: DCE-MRI is a noninvasive method which can characterize microcirculation in rectal cancer and correlates with EGFR expression. Given the relationship between the dynamic parameters and the clinicopathologic data, DCE-MRI data may constitute a prognostic indicator for lymph node and distant metastases in patients with rectal cancer.

Prediction of lymphovascular invasion in rectal cancer by preoperative CT.

OBJECTIVE: The purpose of this study was to investigate whether the diameter of superior hemorrhoidal vein on preoperative CT can predict the presence of lymphovascular invasion (LVI). SUBJECTS AND METHODS: This study recruited 102 patients with treatment-naive rectal cancers. The diameters of superior hemorrhoidal vein and inferior mesenteric vein (IMV) on pretreatment CT and postoperative pathologic reports were reviewed. Univariate analysis and receiver operating characteristic curve analysis were applied to determine the correlation between clinical factors and pathologic features and the diameters of superior hemorrhoidal vein and IMV. RESULTS: The diameter of superior hemorrhoidal vein was significantly higher in patients with LVI than in those without (mean diameter, 44 vs 30 mm, respectively; p < 0.001) and was significantly higher in patients with distant metastases than in those without (p = 0.044). There was no significant difference between IMV diameter in LVI and that in distant metastasis (p = 0.521). CONCLUSION: Patients having rectal cancers with LVI showed a significantly increased mean superior hemorrhoidal vein diameter at presentation, which could be identified with pretreatment CT and help to direct the application of neoadjuvant treatment strategies.

Antitumor effect of FP3 on a patient-derived tumor tissue xenograft model of rectal carcinoma.

BACKGROUND/AIMS: FP3 is an engineered protein which contains the extracellular domain 2 of VEGF receptor 1 (Flt-1) and extracellular domain 3 and 4 of VEGF receptor 2 (Flk-1, KDR) fused to the Fc portion of human immunoglobulin G1. Previous studies demonstrated its antiangiogenic and antitumor effects in vitro and in vivo. METHODOLOGY: In this study, a PDTT xenograft model of rectal carcinoma was established for assessment of the antitumor activity of FP3. Xenografts were treated with FP3 or bevacizumab (Avastin). After tumor growth was confirmed, volume and microvessel density in tumors were evaluated. Levels of VEGF and PCNA in the tumor were examined by immunohistonchemical staining and western blotting. RESULTS: FP3 showed significant antitumor activity in the PDTT xenograft model of rectal carcinoma. The microvessel density in tumor tissues treated with FP3 was lower than that of the control. Antitumor activity of FP3 was similar to that of bevacizumab in the PDTT xenograft model of rectal carcinoma. CONCLUSIONS: This study indicated that FP3 could be used as an effective antiangiogenic and antitumor agent in treatment of colorectal carcinoma.

Verification of blood flow path reconstruction mechanism in distal sigmoid colon and rectal cancer after high IMA ligation through preoperative and postoperative comparison by manual subtraction CTA.

INTRODUCTION: We aimed to investigate manual subtraction computed tomography angiography (MS-CTA) to further confirm the distribution and classification of LCA (left colic artery) ascending/descending branches, then observe the postoperative blood flow path to illustrate how the above branches evolved to postoperative blood path. MATERIAL AND METHODS: 89 patients with distal sigmoid and rectal cancer were referred in our observation and underwent MS-CTA between June 2020 and March 2022. We classified the distribution of LCA and confirmed whether there exists AMCA (accessory middle colic artery). Then we planned blood flow path based on the classification of LCA branches before operation. High ligation was applied in regular radical surgery. During operation, we carefully protect the bifurcation of ascending and descending LCA. Then we compared the planned blood flow path with the actual postoperative blood flow path to verify the mechanism we proposed previously. RESULTS: Of 89 patients, 82 cases met our criteria, we summarized 6 distribution pattens of LCA ascending and descending branches. These preoperative pattens are consistent with the inspection during operation. The postoperative blood flow path of 6 pattens is evolved from the above adjacent anastomotic branches and is consistent with the planned blood flow path. We also found 2 cases with IMA stenosis and 1 case with SMA stenosis under pathological condition, and their compensatory blood flow path is in accordance with our theory. The rate of the anastomotic leakage in our study group is relatively low (7.3%). CONCLUSION: MS-CTA could confirm the distribution of LCA and AMCA, display accurate postoperative blood reconstruction path after IMA high ligation, and it further verified the mechanism we proposed previously, which is the proximal anastomotic branches forming new blood flow path from high-pressure area to the low-pressure area. This mechanism might be helpful for performing accurate laparoscopic sigmoid and rectal cancer surgery.

Reproducibility of 2D and 3D fractal analysis techniques for the assessment of spatial heterogeneity of regional blood flow in rectal cancer.

PURPOSE: To characterize the two-dimensional (2D) and three-dimensional (3D) fractal properties of rectal cancer regional blood flow assessed by using volumetric helical perfusion computed tomography (CT) and to determine its reproducibility. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. Ten prospective patients (eight men, two women; mean age, 72.3 years) with rectal adenocarcinoma underwent two repeated volumetric helical perfusion CT studies (four-dimensional adaptive spiral mode, 11.4-cm z-axis coverage) without intervening treatment within 24 hours, with regional blood flow derived by using deconvolution analysis. Two-dimensional and 3D fractal analyses of the rectal tumor were performed, after segmentation from surrounding structures by using thresholding, to derive fractal dimension and fractal abundance. Reproducibility was quantitatively assessed by using Bland-Altman statistics. Two-dimensional and 3D lacunarity plots were also generated, allowing qualitative assessment of reproducibility. Statistical significance was at 5%. RESULTS: Mean blood flow was 63.50 mL/min/100 mL ± 8.95 (standard deviation). Good agreement was noted between the repeated studies for fractal dimension; mean difference was -0.024 (95% limits of agreement: -0.212, 0.372) for 2D fractal analysis and -0.024 (95% limits of agreement: -0.307, 0.355) for 3D fractal analysis. Mean difference for fractal abundance was -0.355 (95% limits of agreement: -0.869, 1.579) for 2D fractal analysis and -0.043 (95% limits of agreement: -1.154, 1.239) for 3D fractal analysis. The 95% limits of agreement were narrower for 3D than 2D analysis. Lacunarity plots also visually confirmed close agreement between repeat studies. CONCLUSION: Regional blood flow in rectal cancer exhibits fractal properties. Good reproducibility was achieved between repeated studies with 2D and 3D fractal analysis.