Impact of sex and socioeconomic status on the likelihood of surgery, hospitalization, and use of medications in inflammatory bowel disease: a systematic review and meta-analysis.

BACKGROUND: Inflammatory bowel diseases (IBDs) are associated with high healthcare utilization. This systematic review aimed to summarize what is known about the impact of sex, income, and education on the likelihood of bowel surgery, hospitalization, and use of corticosteroids and biologics among patients with IBD. METHODS: We used EMBASE, MEDLINE, CINAHL, and Web of Science to perform a systematic literature search. Pooled hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random effects meta-analysis for the impact of sex on the likelihood of surgery and hospitalization. In addition, we performed subgroup analyses of the effect of IBD type (Crohn's disease or ulcerative colitis) and age. Finally, meta-regression was undertaken for the year of publication. RESULTS: In total, 67 studies were included, of which 23 studies were eligible for meta-analysis. In the main meta-analysis, male sex was associated with an increased likelihood of bowel surgery (HR 1.42 (95% CI 1.13;1.78), which was consistent with the subgroup analysis for UC only (HR 1.78, 95% CI 1.16; 2.72). Sex did not impact the likelihood of hospitalization (OR 1.05 (95% CI 0.86;1.30), although the subgroup analysis revealed an increased likelihood of hospitalization in CD patients (OR 1.42, 95% CI 1.28;1.58). In 9 of 10 studies, no significant sex-based differences in the use of biologics were reported, although in 6 of 6 studies, female patients had lower adherence to biologics. In 11 of 13 studies, no significant sex-based difference in the use of corticosteroids was reported. The evidence of the impact of income and education on healthcare utilization was sparse and pointed in different directions. The substantial heterogeneity between studies was explained, in part, by differences in IBD type and age. CONCLUSIONS: The results of this systematic review indicate that male patients with IBD are significantly more likely to have surgery than female patients with IBD but are not, overall, more likely to be hospitalized, whereas female patients appear to have statistically significantly lower adherence to biologics compared to male patients. Thus, clinicians should not underestimate the impact of sex on healthcare utilization. Evidence for income- and education-based differences remains sparse. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42022315788.

Poly-ϵ-caprolactone scaffold as staple-line reinforcement of rectal anastomosis: an experimental piglet study.

PURPOSE: Rectal anastomoses have a persisting high incidence of anastomotic leakage. This study aimed to assess whether the use of a poly-ϵ-caprolactone (PCL) scaffold as reinforcement of a circular stapled rectal anastomosis could increase tensile strength and improve healing compared to a control in a piglet model. METHOD: Twenty weaned female piglets received a stapled rectal anastomosis and were randomised to either reinforcement with PCL scaffold (intervention) or no reinforcement (control). On postoperative day five the anastomosis was subjected to a tensile strength test followed by a histological examination to evaluate the wound healing according to the Verhofstad scoring. RESULTS: The tensile strength test showed no significant difference between the two groups, but histological evaluation revealed significant impaired wound healing in the intervention group. CONCLUSION: The incorporation of a PCL scaffold into a circular stapled rectal anastomosis did not increase anastomotic tensile strength in piglets and indicated an impaired histologically assessed wound healing.

Proteomic Profiling of Colorectal Adenomas Identifies a Predictive Risk Signature for Development of Metachronous Advanced Colorectal Neoplasia.

BACKGROUND & AIMS: Colonic adenomatous polyps, or adenomas, are frequent precancerous lesions and the origin of most cases of colorectal adenocarcinoma. However, we know from epidemiologic studies that although most colorectal cancers (CRCs) originate from adenomas, only a small fraction of adenomas (3%-5%) ever progress to cancer. At present, there are no molecular markers to guide follow-up surveillance programs. METHODS: We profiled, by mass spectrometry-based proteomics combined with machine learning analysis, a selected cohort of formalin-fixed, paraffin-embedded high-grade (HG) adenomas with long clinical follow-up, collected as part of the Danish national screening program. We grouped subjects in the cohort according to their subsequent history of findings: a nonmetachronous advanced neoplasia group (G0), with no new HG adenomas or CRCs up to 10 years after polypectomy, and a metachronous advanced neoplasia group (G1) where individuals developed a new HG adenoma or CRC within 5 years of diagnosis. RESULTS: We generated a proteome dataset from 98 selected HG adenoma samples, including 20 technical replicates, of which 45 samples belonged to the nonmetachronous advanced neoplasia group and 53 to the metachronous advanced neoplasia group. The clear distinction of these 2 groups seen in a uniform manifold approximation and projection plot indicated that the information contained within the abundance of the ∼5000 proteins was sufficient to predict the future occurrence of HG adenomas or development of CRC. CONCLUSIONS: We performed an in-depth analysis of quantitative proteomic data from 98 resected adenoma samples using various novel algorithms and statistical packages and found that their proteome can predict development of metachronous advanced lesions and progression several years in advance.

Clinical procedures used to diagnose inflammatory bowel disease: real-world evidence from a Danish nationwide population-based study.

OBJECTIVE: Although clinical guidelines exist, the diagnostic work-up for diagnosing inflammatory bowel disease (IBD) is complex and varies in clinical practice. This study used real-life data to characterise the current diagnostic procedures used to establish IBD diagnoses in a Danish nationwide setting. DESIGN: Person-level data on patients diagnosed with IBD between 1 January 2014 and 30 June 2018 were linked between Danish health registers. Information on age, sex, registration of other gastrointestinal diseases, and diagnostic procedures (endoscopies, biopsies, and imaging) performed in relation to the first IBD hospital admission was analysed for the total study population and was stratified by IBD type, sex, and age. RESULTS: The majority of the 12 871 patients with IBD included underwent endoscopy (84%), had a biopsy taken (84%), and/or underwent imaging procedures (44%). In total, 7.5% of the population (6% for Crohn's disease and 8% for ulcerative colitis) were diagnosed with IBD despite not undergoing any of these diagnostic procedures. Patients with Crohn's disease underwent more procedures than patients with ulcerative colitis (94% vs 92%, p<0.001). Children underwent slightly fewer diagnostic procedures than adults (92% vs 93%, p=0.004). Slightly more men underwent at least one procedure than women (92% vs 94%, p<0.001). CONCLUSION: For 7.5% of patients with IBD, this study did not detect any registrations of the recommended diagnostic procedures for establishing an IBD diagnosis. Further research is needed to examine whether these findings are mainly explained by limitations of the register data or also indicate shortcomings of the general approach to IBD.

Segmental reversal of the distal small intestine in a short bowel syndrome model in piglets showed detrimental effect on weight gain.

BACKGROUND: To investigate the effects of a reversed segment of the distal small intestine to improve weight gain in an experimental short bowel syndrome (SBS) model in piglets. METHODS: Twenty-four piglets underwent resection of 70% of the distal small intestine. In half of the animals a conventional anastomosis was performed, and in the other half, the distal 25 cm of the remnant jejunum was reversed before the intestinal continuity was recreated. Weight was measured daily until day 28, where the animals were euthanized. Glucagon-Like Peptide-2 (GLP-2) and Glucose-dependent Insulinotropic Peptide (GIP) was measured pre- and postoperatively at day 28. RESULTS: The group with reversal of small intestine had a significant lower weight gain at 5.26 ± 3.39 kg (mean ± SD) compared to the control group with 11.14 ± 3.83 kg (p < 0.05). In the control group greater villus height and crypt depth was found distally, and greater muscular thickness was found proximally in the intervention group. GLP-2 and GIP levels increased significantly in the control group. CONCLUSIONS: Treatment of short bowel syndrome with a reversed jejunal segment of 25 cm had a detrimental effect on the weight gain.

Pediatric Celiac Disease and Selective IgA Deficiency: Unexpected Sequence of Events.

PURPOSE: Selective IgA deficiency (IgAD) is the most common primary immunodeficiency, frequently leading to only minor clinical complaints. IgAD may be associated with autoimmune diseases such as celiac disease (CeD). Although IgAD is thought to precede CeD and autoimmunity, the association between the two conditions has not been clarified. METHODS: Routine techniques were used to measure serum IgA and celiac diagnostic markers as transglutaminase 2 IgA (TG2-IgA) and deamidated gliadin IgG and for immunohistochemistry for IgG, IgM, and IgA. RESULTS: We report two childhood cases of complete IgA deficiency that evolved after the diagnosis of CeD and the start of a gluten-free diet. Histology showed persistence of IgA in the intestinal mucosa. CONCLUSION: Both children with CeD showed IgA deficiency that unexpectedly developed after the initiation of a gluten-free diet. This supports IgA deficiency as a process that develops gradually and occurs due to specific defects in immunoregulation.

Small intestine necrosis in catastrophic antiphospholipid syndrome: A rare and severe case.

Catastrophic antiphospholipid syndrome (CAPS) is a multisystem autoimmune disease with widespread thrombotic events. In this case report, we present a young man with primary antiphospholipid syndrome (PAPS) admitted to the hospital with abdominal pain and vomiting. Abdominal computed tomography showed pneumoperitoneum and acute explorative laparotomy revealed small intestinal necrosis indicating small vessel thrombosis without involvement of large intestine. "Triple therapy" was initiated after surgery and the patient was treated in an intensive care unit for 72 days before being discharged to a rehabilitation clinic. A review of the literature regarding CAPS affecting small intestine shows it is extremely rare and may be associated with higher mortality.

Remote ischemic postconditioning has a detrimental effect and remote ischemic preconditioning seems to have no effect on small intestinal anastomotic strength.

BACKGROUND: The effect of remote pre- and postconditioning on anastomotic healing has been sparsely studied. The aim of our study was to investigate whether remote ischemic conditioning (RIC) applied before and after the creation of a small bowel anastomosis had an effect on anastomotic healing on postoperative day five evaluated by a tensile strength test and histological analysis. MATERIALS AND METHODS: Twenty-two female piglets were randomized into two groups. The intervention group (n = 12) received RIC on the forelimbs consisting of 15 min of ischemia followed by 30 min of reperfusion before the first end-to-end ileal anastomosis was created. The RIC procedure was repeated and the second and more distal anastomosis was performed. The control group (n = 10) had two similar anastomoses with similar time intervals but without RIC. On postoperative day five, the anastomoses were subjected to macroscopic evaluation, tensile strength test and histological examination. RESULTS: Mean tensile strength when the first transmural rupture appeared (MATS-2) was significantly lower in the first anastomosis in the intervention group compared to the control group (11.4 N vs 14.7 N, p < .05). Similar result was found by the maximal strength (MATS-3) as defined by a drop in the load curve (12.3 N vs 15.9 N, p < .05). Histologically, a significantly higher necrosis score was found in the anastomosis in the intervention group (1.4 vs 0.8, p < .05). No other significant differences were found. CONCLUSIONS: In conclusion, post-anastomotic remote ischemic conditioning had a detrimental effect and pre-anastomotic conditioning seems to have no effect on small intestinal anastomotic strength.

A Serological Biomarker of Laminin Gamma 1 Chain Degradation Reflects Altered Basement Membrane Remodeling in Crohn's Disease and DSS Colitis.

BACKGROUND: The laminin gamma 1 chain (LMγ1) is abundant along the crypt-villus axis in the intestinal basement membrane. AIMS: We investigated whether a serological biomarker of laminin degradation was associated with disease activity in patients with Crohn's disease (CD) and in rats with dextran sulfate sodium (DSS)-induced colitis. METHODS: Serum samples from CD patients (n = 43), healthy subjects (n = 19), and Sprague Dawley rats receiving 5-6% DSS water for five days and regular drinking water for 11 days were included in this study. The LG1M biomarker, a neo-epitope degradation fragment of the LMγ1 chain generated by matrix metalloproteinases-9 (MMP-9), was measured in serum to estimate the level of laminin degradation. RESULTS: Serum LG1M was elevated in CD patients with active and inactive disease compared to healthy subjects (p < 0.0001). LG1M distinguished CD patients from healthy subjects, with an area under the curve (AUC) of 0.81 (p < 0.0001). Serum LG1M was decreased in DSS rats compared to controls 2 days after DSS withdrawal, and increased upon reversal of the disease. CONCLUSIONS: Increased serum LG1M in active and inactive CD patients supports the evidence of altered LM expression in both inflamed and non-inflamed tissue. Moreover, lower LG1M levels in the early healing phase of DSS-induced colitis may reflect ongoing mucosal repair.

Peptidoglycan Recognition Peptide 2 Aggravates Weight Loss in a Murine Model of Chemotherapy-Induced Gastrointestinal Toxicity.

Introduction: Chemotherapy-induced gastrointestinal toxicity (CIGT) is a frequent, severe and dose-limiting side effect. Few treatments have proven effective for CIGT. CIGT is characterized by activation of the nuclear factor kappa B pathway which, leads to upregulation of proinflammatory cytokines. The innate immune protein peptidoglycan recognition peptide 2 (PGLYRP2) binds to and hydrolyzes microbial peptidoglycan. Expression of PGLYRP2 is upregulated in the intestine of chemotherapy-treated piglets. In this experimental study, we investigated the role of Pglyrp2 in the development and severity of murine CIGT. Methods: Pglyrp2 wildtype and Pglyrp2 knockout mice received intraperitoneal injections of chemotherapy (Doxorubicin 20 mg/kg) to induce CIGT. Weight was monitored daily, and animals were euthanized after 2 or 7 days. Expression of proinflammatory cytokines in the jejunum was measured by quantitative real-time polymerase-chain reaction and enzyme-linked immunosorbent assay. Villus height, crypt depth, and histologic inflammation were evaluated on haematoxylin and eosin stained tissue specimens. Results: Chemotherapeutic treatment induced weight loss (p < 0.05), shortening of the small intestine (p < 0.05), elongation of villus height (p < 0.05), increased crypt depth (p < 0.05), and led to elevated mRNA levels of II1ß (p < 0.05), II6 (p < 0.05), and Tnf (p < 0.001) at day 2. Protein levels of IL1ß, IL6, and TNFα did not change after exposure to chemotherapy. Doxorubicin treated wildtype mice had a more pronounced weight loss compared to knockout mice from day 3 to day 7 (D3-D6: p < 0.05 and D7: p < 0.01). No other phenotypic differences were detected. Conclusion: Pglyrp2 aggravates chemotherapy-induced weight loss but does not induce a specific pattern of inflammation and morphological changes in the small intestine.

Incorporation of a Poly-ε-Caprolactone Scaffold in a ;Circular Stapled End-To-End Small Intestine Anastomosis Does Not Have Any Adverse Effects Within 30 days: A Study in Piglets.

Background. Incorporation of a poly-ε-caprolactone (PCL) scaffold in circular stapled anastomoses has been shown to increase the anastomotic tensile strength on postoperative day (POD) 5 in a pig model. The aim of this study was to investigate the effects of incorporation of a PCL scaffold in a circular stapled end-to-end small intestine anastomosis, with stricture formation and anastomotic histology as primary outcomes in a 30-day observation period. Methods. A total of 15 piglets were included. In each piglet, three circular stapled end-to-end anastomoses were made in the small intestines. Two were interventional and one was a control. On POD 10, 20, or 30, the anastomoses were subjected to in vivo intraluminal contrast study, and the index for anastomotic lumen was calculated. The anastomotic segment was resected and subjected to a tensile strength test and histological examination. Results. At POD 10, the mean ± SD value for anastomotic index was .749 ± .065 in control anastomoses and .637 ± .051 in interventional anastomosis (P = .0046), at POD 20, .541 ± .150 and .724 ± .07 (P = .051), and at POD 30, .645 ± .103 and .686 ± .057 (P = .341), respectively. No significant difference was observed in maximum tensile strength and histology at POD 30. Conclusions. The incorporation of a PCL scaffold in a circular stapled end-to-end small intestine anastomosis does not increase the risk of stricture or impair wound healing after 30 days.

FIBCD1 ameliorates weight loss in chemotherapy-induced murine mucositis.

PURPOSE: Chemotherapy-induced gastrointestinal toxicity is a common adverse event during chemotherapeutic treatment. No uniformly applicable strategies exist to predict, prevent, or treat gastrointestinal toxicity. Thus, a goal of mucositis research is to identify targets for therapeutic interventions and individualized risk prediction. Fibrinogen C domain containing 1 (FIBCD1) is a transmembrane protein expressed in human intestinal epithelial cells with functions in the innate immune system. Previous observations have shown that FIBCD1 ameliorates dextran sulfate sodium (DSS)-induced intestinal inflammation in vivo. We evaluated the effect of FIBCD1 in a murine model of chemotherapy-induced gastrointestinal toxicity and inflammation. METHODS: Transgenic (Tg) mice overexpressing FIBCD1 in the intestinal epithelium (Fibcd1Tg) and wild-type (WT) littermates (C57BL/6N) were randomized to receive an intraperitoneal injection of doxorubicin 20 mg/kg or saline and were terminated 2 or 7 days after the injection. Gastrointestinal toxicity was evaluated by weight change, intestinal length, villus height/crypt depth, and histological mucositis score. Expression of inflammatory markers (IL-6, IL-1ß, and Tnfα) was measured by quantitative real-time PCR in intestinal tissue samples. RESULTS: Following doxorubicin treatment, WT mice exhibited an increased weight loss compared with Tg littermates (p < 0.001). No differences between genotypes were seen in mucositis score, intestinal length, villus height/crypt depth, or IL-6, IL-1ß, and Tnfα expression. CONCLUSION: Our findings suggest that FIBCD1 could ameliorate chemotherapy-induced gastrointestinal toxicity by reducing weight loss; however, the mechanism of this possible protective effect remains to be defined warranting additional investigations.

Remote ischemic conditioning in active ulcerative colitis: An explorative randomized clinical trial.

Remote ischemic conditioning (RIC) by repetitive brief periods of limb ischemia and reperfusion renders organs more resistant to ischemic injury. The protection is partly through down-regulation of the inflammatory response. Our aim was to investigate the clinical and anti-inflammatory effects of RIC in patients with active ulcerative colitis (UC). We included 22 patients with active UC in this explorative, randomized, sham-controlled clinical trial. The patients were randomly assigned 1:1 to RIC (induced in the arm through four cycles of 5-min inflation and 5-min deflation of a blood-pressure cuff) or sham (incomplete inflation of the blood-pressure cuff) once daily for 10 days. Outcome variables were measured at baseline and on day 11. When compared with sham, RIC did not affect inflammation in the UC patients measured by fecal calprotectin, plasma C-reactive protein, Mayo Score, Mayo Endoscopic Subscore, Nancy Histological Index or inflammatory cytokines involved in UC and RIC. The mRNA and miRNA expression profiles in the UC patients were measured by RNA sequencing and multiplexed hybridization, respectively, but were not significantly affected by RIC. We used the Langendorff heart model to assess activation of the organ protective mechanism induced by RIC, but could not confirm activation of the organ protective mechanism in the UC patients.

A streamlined mass spectrometry-based proteomics workflow for large-scale FFPE tissue analysis.

Formalin fixation and paraffin-embedding (FFPE) is the most common method to preserve human tissue for clinical diagnosis, and FFPE archives represent an invaluable resource for biomedical research. Proteins in FFPE material are stable over decades but their efficient extraction and streamlined analysis by mass spectrometry (MS)-based proteomics has so far proven challenging. Herein we describe a MS-based proteomic workflow for quantitative profiling of large FFPE tissue cohorts directly from histopathology glass slides. We demonstrate broad applicability of the workflow to clinical pathology specimens and variable sample amounts, including low-input cancer tissue isolated by laser microdissection. Using state-of-the-art data dependent acquisition (DDA) and data independent acquisition (DIA) MS workflows, we consistently quantify a large part of the proteome in 100 min single-run analyses. In an adenoma cohort comprising more than 100 samples, total workup took less than a day. We observed a moderate trend towards lower protein identification in long-term stored samples (>15 years), but clustering into distinct proteomic subtypes was independent of archival time. Our results underscore the great promise of FFPE tissues for patient phenotyping using unbiased proteomics and they prove the feasibility of analyzing large tissue cohorts in a robust, timely, and streamlined manner. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Extracellular Matrix Fragments of the Basement Membrane and the Interstitial Matrix Are Serological Markers of Intestinal Tissue Remodeling and Disease Activity in Dextran Sulfate Sodium Colitis.

BACKGROUND: Chronic intestinal inflammation results in tissue damage partly caused by an increase in matrix metalloproteinases (MMP) activity causing degradation of extracellular matrix (ECM) proteins. We studied intestinal tissue remodeling by quantifying ECM protein fragments in serum in dextran sulfate sodium (DSS)-induced colitis, to investigate ECM protein fragments as serological biomarkers of intestinal tissue remodeling and disease activity. METHODS: Male Sprague-Dawley rats received 5% DSS in drinking water for 5 days followed by 11 days with regular water. Disease activity index (DAI) was scored daily. Serum was collected on day 0, 6, 7, and 16. ELISAs were used to quantify MMP-derived remodeling fragments of basement membrane type IV collagen (C4M and PRO-C4) and interstitial matrix type III collagen (C3M and rPRO-C3). RESULTS: In DSS rats, serum levels relative to baseline of C4M, PRO-C4, and C3M were elevated (P < 0.01; P < 0.001; P < 0.001) at day 7, which declined at day 16. Levels of rPRO-C3 were lower in DSS rats at day 7 and increased to normal levels at day 16. The ratio between C3M and rPRO-C3 showed an overall degradation (P < 0.0001) of collagen type III in DSS rats at day 7, which correlated to the DAI (r2 = 0.5588, P < 0.0001). CONCLUSION: Our data suggest that remodeling of the basement membrane (C4M and PRO-C4) and the interstitial matrix (C3M and rPRO-C3) increased during DSS-induced colitis and declined with reversal of the disease. Thus, serological biochemical biomarkers of the ECM reflect tissue remodeling and could be studied as markers of disease activity in IBD.

Segmental reversal of distal small intestine in short bowel syndrome: a study on the influence on postoperative weight and intestinal topography in piglets.

PURPOSE: The objective of the present study was to investigate the effect of segmental reversal of the distal 20 cm of the small intestine in piglets with induced SBS compared to controls with SBS alone. Primary endpoint was postoperative weight change over a period of 1 month. Secondary endpoints were the influence on cell proliferation and mucosal architecture shown by histological analysis. METHODS: Sixteen piglets underwent a 60% resection of the distal small intestine and were randomized into two groups. Group 1 short bowel syndrome alone (SBS) (n = 8) and group 2 with reversal of a distal small intestinal segment (SBS-RS) (n = 8). Body weight was measured daily and the pigs were euthanized after 1 month. Crypt depths, villus heights and muscle layers thicknesses were measured. For the evaluation of microvilli of the brush border of the epithelium and cell proliferation, immunohistochemical staining with Villin and Ki-67 was performed. RESULTS: No statistically significant differences were observed concerning weight gain. Mean ± SD weight gain was 2.31 ± 2.85 kg for SBS-RS and 2.03 ± 1.27 kg for SBS (p = 0.8). In the proximal jejunal segment a significant increase in villus heights was found in the SBS group and increase in the thickness of the circular and longitudinal muscle layers in the SBS-RS group. In the distal ileal segment the longitudinal muscle layer thicknesses were increased in the SBS group. Otherwise, no significant changes were found. CONCLUSION: Reversal of a 20-cm distal segment showed no effect on weight gain, but there were some significant histological changes of unknown clinical significance.

Dual-Energy CT of Rectal Cancer Specimens: A CT-based Method for Mesorectal Lymph Node Characterization.

BACKGROUND: An accurate method to assess malignant lymph nodes in the mesorectum is needed. Dual-energy CT scans simultaneously with 2 levels of energy and thereby provides information about tissue composition based on the known effective Z value of different tissues. Each point investigated is represented by a certain effective Z value, which allows for information on its composition. OBJECTIVE: We wanted to standardize a method for dual-energy scanning of rectal specimens to evaluate the sensitivity and specificity of benign versus malignant lymph node differentiation. Histopathological evaluation of the nodes was our reference. DESIGN: This was a descriptive and prospective study. SETTINGS: Seventeen rectal specimens were examined in 2 series. The first series was conducted with 3 specimens from patients who were not given perioperative contrast; 3 had iodine-based contrast and 3 had gadolinium-based contrast. We concluded that iodine was the contrast agent of choice and therefore included 8 more patients in a second series, given iodine-based contrast, for further analysis. PATIENTS: Quantitative imaging data were collected from 197 individual lymph nodes from 17 specimens, from patients with rectal cancer. MAIN OUTCOME MEASURES: We measured accuracy of differentiating benign from malignant lymph nodes by investigating the following: 1) gadolinium, iodine, and water concentrations in lymph nodes; 2) dual-energy ratio; 3) dual-energy index; and 4) effective Z value. RESULTS: Optimal discriminations between benign and malignant lymph nodes were obtained using the following cutoff values: 1) effective Z at 7.58 (sensitivity, 100%; specificity, 90%; and accuracy, 93%), 2) dual-energy ratio at 1.0 × 10 (sensitivity, 96%; specificity, 87%; and accuracy, 90%), 3) dual-energy index at 0.03 (sensitivity, 97%; specificity, 88%; and accuracy, 91%), and 4) iodine concentration at 2.58 µg/mL (sensitivity, 86%; specificity, 92%; and accuracy, 89%). LIMITATIONS: The investigation is conducted on isolated surgical specimens from rectal cancer operations. CONCLUSIONS: Dual-energy CT can be performed on rectal specimens. The discrimination between benign and malignant nodes seems promising when using iodine as contrast.