Primary gastroduodenal tuberculosis presenting as gastric outlet obstruction:A case report and review of literature

BACKGROUND Mycobacterium tuberculosis(TB)is the causative agent of TB,a chronic granulo-matous illness.This disease is prevalent in low-income countries,posing a significant global health challenge.Gastrointestinal TB is one of the three forms.The disease can mimic other intra-abdominal conditions,leading to delayed diagnosis owing to the absence of specific symptoms.While gastric outlet obs-truction(GOO)remains a frequent complication,its incidence has declined with the advent of proton pump inhibitors and Helicobacter pylori eradication therapy.Gastroduodenal TB can cause upper gastrointestinal hemorrhage,obstruction,and malignancy-like tumors.CASE SUMMARY A 23-year-old male presented with recurrent epigastric pain,distension,nausea,vomiting,and weight loss,prompting a referral to a gastroenterologist clinic.Endoscopic examination revealed distorted gastric mucosa and signs of chronic inflammation.However,treatment was interrupted,possibly owing to vomiting or comorbidities such as human immunodeficiency virus infection or diabetes.Subsequent surgical intervention revealed a dilated stomach and diffuse thickening of the duodenal wall.Resection revealed gastric wall effacement with TB.CONCLUSION Primary gastric TB is rare,frequently leading to GOO.Given its rarity,suspicions should be promptly raised when encountering relevant symptoms,often requiring surgical intervention for diagnosis and treatment.

Endoscopic-ultrasound-guided biliary drainage with placement of electrocautery-enhanced lumen-apposing metal stent for palliation of malignant biliary obstruction:Updated meta-analysis

BACKGROUND Endoscopic ultrasound-guided biliary drainage using electrocautery-enhanced(ECE)delivery of lumen-apposing metal stent(LAMS)is gradually being re-cognized as a viable palliative technique for malignant biliary obstruction after endoscopic retrograde cholangiopancreatography(ERCP)failure.However,most of the studies that have assessed its efficacy and safety were small and hetero-geneous.Prior meta-analyses of six or fewer studies that were published 2 years ago were therefore underpowered to yield convincing evidence.AIM To update the efficacy and safety of ECE-LAMS for treatment of biliary ob-struction after ERCP failure.METHODS We searched PubMed,EMBASE,and Scopus databases from the inception of the ECE technique to May 13,2022.Primary outcome measure was pooled technical success rate,and secondary outcomes were pooled rates of clinical success,re-intervention,and adverse events.Meta-analysis was performed using a random-effects model following Freeman-Tukey double-arcsine transformation in R soft-ware(version 4.1.3).RESULTS Fourteen eligible studies involving 620 participants were ultimately included.The pooled rate of technical success was 96.7%,and clinical success was 91.0%.Adverse events were reported in 17.5%of patients.Overall reinter-vention rate was 7.3%.Subgroup analyses showed results were generally consistent.CONCLUSION ECE-LAMS has favorable success with acceptable adverse events in relieving biliary obstruction when ERCP is impossible.The consistency of results across most subgroups suggested that this is a generalizable approach.

Response letter to “Acute cholangitis: Does malignant biliary obstruction vs choledocholithiasis etiology change the outcomes?” with imaging aspects

Radiological imaging findings may contribute to the differentiation of malignant biliary obstruction from choledocholithiasis in the etiology of acute cholangitis.

Case of abdominal whirl sign with small bowel obstruction and free gas successfully managed by conservative management instead of laparoscopic surgery

The whirl sign refers to the computed tomography(CT)radiological finding of swirl of the small bowel and adjacent mesenteric soft tissue around the twisted mesenteric vessel.The whirl sign is highly specific for small bowel volvulus(SBV)and raises the suspicion of closed loop obstruction.Nearly all patients with whirl signs associated with small bowel obstruction(SBO)require operative intervention,and one study showed that patients with whirl signs are 25 times more likely to need surgery.

Defining minimal invasive surgical therapy for benign prostatic obstruction surgery: Perspectives from a global knowledge, attitude, and practice survey

Objective:To scrutinize the definitions of minimal invasive surgical therapy(MIST)and to investigate urologists’knowledge,attitudes,and practices for benign prostatic obstruction surgeries.Methods:A 36-item survey was developed with a Delphi method.Questions on definitions of MIST and attitudes and practices of benign prostatic obstruction surgeries were included.Urologists were invited globally to complete the online survey.Consensus was achieved when more than or equal to 70%responses were“agree or strongly agree”and less than or equal to 15%responses were“disagree or strongly disagree”(consensus agree),or when more than or equal to 70%responses were“disagree or strongly disagree”and less than or equal to 15%responses were“agree or strongly agree”(consensus disagree).Results:The top three qualities for defining MIST were minimal blood loss(n=466,80.3%),fast post-operative recovery(n=431,74.3%),and short hospital stay(n=425,73.3%).The top three surgeries that were regarded as MIST were Urolift®(n=361,62.2%),Rezum®(n=351,60.5%),and endoscopic enucleation of the prostate(EEP)(n=332,57.2%).Consensus in the knowledge section was achieved for the superiority of Urolift®,Rezum®,and iTIND®over transurethral resection of the prostate with regard to blood loss,recovery,day surgery feasibility,and post-operative continence.Consensus in the attitudes section was achieved for the superiority of Urolift®,Rezum®,and iTIND®over transurethral resection of the prostate with regard to blood loss,recovery,and day surgery feasibility.Consensus on both sections was achieved for EEP as the option with the better symptoms and flow improvement,lower retreatment rate,and better suitable for prostate more than 80 mL.Conclusion:Minimal blood loss,fast post-operative recovery,and short hospital stay were the most important qualities for defining MIST.Urolift®,Rezum®,and EEP were regarded as MIST by most urologists.

Management of Acute Bowel Obstruction in Adults in Ziguinchor Hospital Establishments: About 163 Cases Followed Up

Acute intestinal obstruction represents a very frequent admission to surgical emergencies. The aim of our study was to make a descriptive analysis of the management of acute intestinal obstructions at the level of hospital establishments in Ziguinchor. Materials and Methods: This was a retrospective, descriptive, multicenter study from the period of January 1, 2017 to December 31, 2021. Patients over 15 years of age admitted for occlusive syndrome in the two surgical departments of the Ziguinchor regional hospitals were included in the study. Epidemiological, diagnostic, therapeutic and evolutionary data were studied. Results: Acute intestinal occlusions accounted for 8.3% of admissions. A total of 163 patients were enrolled, 61.9% were men, sex ratio of 1.6. The mean age was 48.7 years. The average consultation time was 74.8 hours (3.12 days). The total occlusive syndrome was in 48.5% of the cases. Abdominal pain was present in 87.1%, vomiting in 74.2%, cessation of matter and gas in 60.7% and meteorism in 36.2%. Biological lab tests reported hyperleukocytosis in 28.1% of the cases. Abdominal CT scans were performed in 71.2%, confirming the diagnosis in 90.5% and determining the etiology in 93.1%. The zone of the obstruction in the small bowel was 62.7%, and in the colon in 37.3%. Functional occlusions accounted for 22.7% of cases and mechanical for 77.3%, including 120 cases of strangulation occlusion (95.2%) and 6 cases of obstruction. Etiologies were dominated by adhesions and/or fibrous bands (61.2%). Medical treatment resolved the occlusive syndrome in 9.2% of cases, instrumental treatment in 17.1% and surgical treatment in 77.3%. Adhesiolysis/section of fibrous bands (55.7%), detorsion (14.3%) and resection anastomosis (11.9%) were the most common surgical procedures. Overall morbidity was 11.6%, dominated by surgical site infection (7.14%). The mean resumption of intestinal transit was 2.7 days, and the mean hospital stay was 7.9 days. Overall mortality was 6.7%. Conclusion: Acute intestinal obstruction is a frequent, absolute medical-surgical emergency, with multiple etiologies dominated in our series by adhesions and/or fibrous bands, whose morbi-mortality could be reduced by early and appropriate management before the onset of intestinal necrosis.

Nasal flap preservation in endoscopic dacryocystorhinostomy for nasolacrimal duct obstruction

AIM:To compare surgical outcomes between the conventional endoscopic dacryocystorhinostomy(DCR)and a modified endoscopic DCR for the treatment of nasolacrimal duct obstruction(NLDO),and evaluate factors associated with the surgical success rate.METHODS:Medical records of patients who underwent primary DCR surgery between January 2016 and July 2020 at the Otorhinolaryngology Department of Eye and Ear International Hospital,Lebanon were reviewed.RESULTS:The study group consisted of 50 consecutive modified endoscopic DCR and the control group consisted of 138 consecutive conventional endoscopic DCR.The success rates at 1y were 98.0%(49 out of 50)for modified DCR,significantly higher compared to 84.8%(117/138)for the conventional DCR;there was no significant difference in the success rate throughout the years in terms of both surgical techniques.The modified surgery vs traditional[adjusted odds ratio(aOR)=14.96]and having an adjunctive septoplasty surgery vs not(aOR=3.99)were significantly associated with higher odds of success.CONCLUSION:Mucosal flap preservation and apposition shows significant improvement in the surgical success rate.Moreover,there is no statistically significant difference found in terms of complication rate and mean operative time between the conventional and the modified techniques.

Results of Surgical Management of Malignant Obstruction of the Common Bile Duct in Yaoundé

Introduction: In Cameroon, surgery remains the only approach in malignant obstructions of the common bile duct (MOCBD) even in palliative situations. The aim of this work was to describe the modalities of surgical treatment of MOCBD, evaluate the results and detect the factors associated with postoperative morbidity and mortality. Patients and Methods: We conducted an analytical observational study, with retrospective data collection from the files of patients operated upon for MOCBD. This was done in four referral hospitals in the city of Yaoundé for a 42-month period spanning from January 1, 2020 to June 30, 2023. Demographic data, clinical presentation, surgical data, and 30-day postoperative outcomes were collected. Results: We collected 71 files. The sex ratio was 1.4 and the mean age was 56 ± 11 years. Fifty-three (53) patients (74.6%) were overweight or obese and 10 patients (14.1%) were hypertensive. A clinical cholestasis syndrome was present in 69 patients (97.2%). Fifty-five (55) patients (77.5%) had a cancer of the head of the pancreas, 8 patients (11.3%) had an extra-hepatic cholangiocarcinoma and 8 patients (11.3%) had an ampullary adenocarcinoma. Eight (8) resections (11.3%) with curative intent had been carried out and in 63 cases (88.7%), surgery was palliative. Postoperative morbidity was 55.7%, influenced by advanced WHO stage (p = 0.02). Postoperative mortality was 25.7%, associated with a high ASA score (p = 0.01). Conclusion: Pancreatic head cancer is the main etiology of malignant obstructions of the common bile duct in Cameroon. Surgical treatment is most often palliative. Postoperative morbidity and mortality are high, influenced by high WHO and ASA scores.

Postoperative abdominal herpes zoster complicated by intestinal obstruction:A case report

BACKGROUND Intestinal obstruction is a common occurrence in clinical practice.However,the occurrence of herpes zoster complicated by intestinal obstruction after abdominal surgery is exceedingly rare.In the diagnostic and treatment process,clinicians consider it crucial to identify the primary causes of its occurrence to ensure effective treatment and avoiding misdiagnosis.CASE SUMMARY Herein,we present the case of a 40-year-old female patient with intestinal obstruction who underwent laparoscopic appendectomy and developed herpes zoster after surgery.Combining the patient's clinical manifestations and relevant laboratory tests,it was suggested that the varicella zoster virus reactivated during the latent period after abdominal surgery,causing herpes zoster.Subsequently,the herpes virus invaded the visceral nerve fibers,causing gastrointestinal dysfunction and loss of intestinal peristalsis,which eventually led to intestinal obstruction.The patient was successfully treated through conservative treatment and antiviral therapy and subsequently discharged from the hospital.CONCLUSION Pseudo-intestinal obstruction secondary to herpes zoster infection is difficult to distinguish from mechanical intestinal obstruction owing to various causes.In cases of inexplicable intestinal obstructions,considering the possibility of a viral infection is essential to minimize misdiagnosis and missed diagnoses。

Role of endoscopic-ultrasound-guided biliary drainage with electrocautery-enhanced lumen-apposing metal stent for palliation of malignant biliary obstruction

In this editorial,we discuss the article by Peng et al in the recent issue of the World Journal of Gastrointestinal Surgery,focusing on the evolving role of endoscopicultrasound-guided biliary drainage(EUS-BD)with electrocautery lumen apposing metal stent(LAMS)for distal malignant biliary obstruction.Therapeutic endoscopy has rapidly advanced in decompression techniques,with growing evidence of its safety and efficacy surpassing percutaneous and surgical approaches.While endoscopic retrograde cholangiopancreatography(ERCP)has been the gold standard for biliary decompression,its failure rate approaches 10.0%,prompting the exploration of alternatives like EUS-BD.This random-effects meta-analysis demonstrated high technical and clinical success of over 90.0% and an adverse event rate of 17.5%,mainly in the form of stent dysfunction.Outcomes based on stent size were not reported but the majority used 6 mm and 8 mm stents.As the body of literature continues to demonstrate the effectiveness of this technique,the challenges of stent dysfunction need to be addressed in future studies.One strategy that has shown promise is placement of double-pigtail stents,only 18% received the prophylactic intervention in this study.We expect this to improve with time as the technique continues to be refined and standardized.The results above establish EUS-BD with LAMS as a reliable alternative after failed ERCP and considering EUS to ERCP upfront in the same session is an effective strategy.Given the promising results,studies must explore the role of EUS-BD as first-line therapy for biliary decompression.

New application of intestinal obstruction catheter in enterocutaneous fistula:A case report

BACKGROUND Enterocutaneous fistula(ECF)is an abnormal connection between the gastrointestinal tract and the skin.ECF can lead to massive body fluid loss,hypercatabolism,and malnutrition.Therefore,nutritional support plays a crucial role in managing ECFs and promoting the healing of fistulas.For nutritional support,enteral nutrition(EN)is the preferred method when gastrointestinal function is recovering.Currently,various EN approaches have been applied for different anatomical positions of the ECF.However,the effectiveness of administering EN support for treating lower ECFs still needs further exploration and improvement.CASE SUMMARY We present the case of a 46-year-old male who underwent gastrointestinal stromal tumour resection.Six days after the surgery,the patient presented with fever,fatigue,severe upper abdominal pain,and septic shock.Subsequently,lower ECFs were diagnosed through laboratory and imaging examinations.In addition to symptomatic treatment for homeostasis,total parenteral nutrition support was administered in the first 72 h due to dysfunction of the intestine.After that,we gradually provided EN support through the intestinal obstruction catheter in consideration of the specific anatomic position of the fistula instead of using the nasal jejunal tube.Ultimately,the patient could receive optimal EN support via the catheter,and no complications were found during the treatment.CONCLUSION Nutritional support is a crucial element in ECF management,and intestinal obstruction catheters could be used for early EN administration.

Imaging features of malignant vs stone-induced biliary obstruction:Aspects to consider

Radiological studies play a crucial role in the evaluation of patients with biliary duct obstruction,allowing for the guidance of clinical diagnosis towards a malignant or stone-induced etiology through the recognition of relevant imaging features,which must be continuously revisited given their prognostic significance.This article aims to emphasize the importance of recognizing crucial imaging aspects of malignant and stone-induced biliary obstruction.

Magnetic compression anastomosis to restore biliary tract continuity after obstruction following major abdominal trauma:A case report

BACKGROUND The combination of magnetic compression anastomosis(MCA)and endoscopy has been used to treat biliary stricture after liver transplantation.However,its use for the treatment of complex biliary obstruction after major abdominal trauma has not been reported.This case report describes the successful use of MCA for the treatment of biliary obstruction resulting from major abdominal trauma.A 23-year-old man underwent major abdominal surgery(repair of liver rupture,right half colon resection,and ileostomy)following a car accident one year ago.The abdominal drainage tube,positioned at the Winslow foramen,was draining approximately 600-800 mL of bile per day.During the two endoscopic retrograde cholangiopancreatography procedures,the guide wire was unable to enter the common bile duct,which prevented placement of a biliary stent.MCA combined with endoscopy was used to successfully achieve magnetic anastomosis of the peritoneal sinus tract and duodenum,and then a choledochoduodenal stent was placed.Finally,the external biliary drainage tube was removed.The patient achieved internal biliary drainage leading to the removal of the external biliary drainage tube,which improved the quality of life.CONCLUSION Magnetic compression technique can be used for the treatment of complex biliary obstruction with minimal operative trauma.

Pharmacodynamic Experiment of Dachengqi Decoction and Separated Decoction on Incomplete Intestinal Obstruction in Rats

[Objectives]To investigate the effect and mechanism of Dachengqi Decoction and separated decoction on incomplete intestinal obstruction in rats.[Methods]80 healthy SD rats were selected to establish incomplete intestinal obstruction model by silk ligation.The dosage was 20 mL/kg for 3 d,and the damage index of ileocecal mucosa was analyzed;the morphology of ileocecal mucosa was observed by HE staining;the serum levels of IL-1α,IL-1β,IL-6,IL-18,Ach,NO,ET,IL-1,TNF-αand ultra-micro Na+-K+-ATPase were detected by ELISA.[Results]Compared with the model group,the mucosal damage index of Dachengqi Decoction and each separated decoction group decreased significantly(P<0.05);compared with the normal group and sham operation group,the serum level of IL-1,IL-6,TNF-αand other factors in the model group increased significantly(P<0.05);compared with the model group,the serum IL-1,IL-6 and TNF-αsecretion levels of rats in Dachengqi Decoction group and separated decoction group decreased(P<0.01).[Conclusions]Dachengqi Decoction and each separated decoction can effectively improve intestinal tissue pathological damage in the incomplete intestinal obstruction model rats,and reduce the inflammatory reaction in the rat body.

Revisiting tuberculosis as a cause of gastric outlet obstruction:Insights from a case report

Gastroduodenal tuberculosis(GD-TB)is exceptionally rare.The clinical manifestations of gastrointestinal TB are diverse and non-specific,which makes diagnosis difficult,leading to delayed diagnosis and high mortality.As a peer-reviewer of World Journal of Clinical Cases,I would like to share my opinion on the article published by this journal.The patient had no family history of TB or contact with people with TB.Primary GD-TB presenting as gastric outlet obstruction and normal findings of thoracic computed tomography increased the difficulty of diagnosis and treatment in this patient.The diagnosis and treatment scheme of this typical case have reference value for the clinical treatment of GD-TB.

Migration of varicocele coil leading to ureteral obstruction and hydronephrosis:A case report

BACKGROUND Varicocele embolization,a minimally invasive treatment for symptomatic varicoceles,carries a rare risk of complications like ureteral obstruction and hydronephrosis.This case report documents such a case to raise awareness of these potential complications and showcase minimally invasive surgical management as a successful solution.CASE SUMMARY A 35-year-old male presented with flank pain and hematuria following varicocele embolization.Imaging confirmed left ureteral obstruction and hydronephrosis.Laparoscopic ureterolysis successfully removed the embolization coil and repaired the ureter,resolving the patient's symptoms.Follow-up at six months and two years showed sustained improvement.CONCLUSION Minimally invasive surgery offers an effective treatment option for rare complications like ureteral obstruction arising from varicocele embolization.

Appendicitis combined with Meckel’s diverticulum obstruction, perforation, and inflammation in children: Three case reports

BACKGROUND Meckel’s diverticulum is a common congenital malformation of the small intestine,with the three most common complications being obstruction,per-foration,and inflammation.To date,only a few cases have been reported world-wide.In children,the clinical symptoms are similar to appendicitis.As most of the imaging features are nonspecific,the preoperative diagnosis is not precise.In addition,the clinical characteristics are highly similar to pediatric acute appendicitis,thus special attention is necessary to distinguish Meckel’s diver-ticulum from pediatric appendicitis.Patients with poor disease control should undergo laparoscopic exploration to avoid serious complications,including intestinal necrosis,intestinal perforation and gastrointestinal bleeding.CASE SUMMARY This report presents three cases of appendicitis in children combined with intestinal obstruction,which was caused by fibrous bands(ligaments)arising from the top part of Meckel's diverticulum,diverticular perforation,and diver-ticular inflammation.All three patients,aged 11-12 years,had acute appendicitis as their initial clinical presentation.All were treated by laparoscopic surgery with a favorable outcome.A complete dataset including clinical presentation,dia-gnostic imaging,surgical information,and histopathologic findings was also provided.CONCLUSION Preoperative diagnosis of Meckel’s diverticulum and its complications is challenging because its clinical signs and complications are similar to those of appendicitis in children.Laparoscopy combined with laparotomy is useful for diagnosis and treatment.

Abdominal cocoon syndrome-a rare culprit behind small bowel ischemia and obstruction:Three case reports

BACKGROUND Abdominal cocoon syndrome(ACS)represents a category within sclerosing encapsulating peritonitis,characterized by the encapsulation of internal organs with a fibrous,cocoon-like membrane of unknown origin,resulting in bowel obstruction and ischemia.Diagnosing this condition before surgery poses a cha-llenge,often requiring confirmation during laparotomy.In this context,we depict three instances of ACS:One linked to intestinal obstruction,the second exclu-sively manifesting as intestinal ischemia without any obstruction,and the final case involving a discrepancy between the radiologist and the surgeon.CASE SUMMARY Three male patients,aged 53,58,and 61 originating from Northern Thailand,arrived at our medical facility complaining of abdominal pain without any prior surgeries.Their vital signs remained stable during the assessment.The diagnosis of abdominal cocoon was confirmed through abdominal computed tomography(CT)before surgery.In the first case,the CT scan revealed capsules around the small bowel loops,showing no enhancement,along with mesenteric congestion affecting both small and large bowel loops,without a clear obstruction.The second case showed intestinal obstruction due to an encapsulated capsule on the CT scan.In the final case,a patient presented with recurring abdominal pain.Initially,the radiologist suspected enteritis as the cause after the CT scan.However,a detailed review led the surgeon to suspect encapsulating peritoneal sclerosis(ACS)and subsequently perform surgery.The surgical procedure involved complete removal of the encapsulating structure,resection of a portion of the small bowel,and end-to-end anastomosis.No complications occurred during surgery,and the patients had a smooth recovery after surgery,eventually discharged in good health.The histopathological examination of the fibrous membrane(cocoon)across all cases consistently revealed the presence of fibro-collagenous tissue,without any indications of malignancy.CONCLUSION Individuals diagnosed with abdominal cocoons commonly manifest vague symptoms of abdominal discomfort.An elevated degree of clinical suspicion,combined with the application of appropriate radiological evaluations,markedly improves the probability of identifying the abdominal cocoon before surgical intervention.In cases of complete bowel obstruction or ischemia,the established norm is the comprehensive removal of the peritoneal sac as part of standard care.Resection with intestinal anastomosis is advised solely when ischemia and gangrene have been confirmed.

Relevance of Medical Imaging in the Pre-Therapeutic Evaluation of Acute Intestinal Obstruction at CIMED

Objective: We initiated this work with the aim of studying the contribution of imaging in the diagnosis of acute intestinal obstruction at CIMED. Patients and methods: This was a prospective, descriptive and analytical study involving 96 patients collected at the radiology and medical imaging department of CIMED, from January 2022 to January 2023. Result: The age of our patients varied between 11 and 86 years with an average age of 36 years. There was a male predominance of 64.6% compared to 35.4% for women, i.e. a sex ratio of 1.82. The notion of previous surgery was found in 61.5% of our patients. Pain was present in all patients. Radiography of the ASP was performed in 89.6% of patients. It showed hydro-aerial levels in 96.5% of patients. Abdominopelvic CT was performed in 12 patients and made it possible to make the diagnosis of occlusion in all patients. The results of the positive diagnosis were concordant with those intraoperatively in 92% of cases. 8% of our patients, compared to the treatment, spontaneously resumed their transit, 91% benefited from surgical treatment and 1% died before surgery. The outcome was favorable in 80 patients or 83.3%, poor with death in 16 patients or 16.7% of cases. Conclusion: Acute intestinal obstruction remains a serious pathology for which ASP radiography often remains the only radiological examination performed urgently. However, abdominopelvic CT seems widely indicated thanks to its contribution both for the positive diagnosis and for the serious and etiological diagnoses. However, this imaging technique is largely underused in our practice due to its high cost and lack of availability.

Gadoxetic acid-enhanced magnetic resonance imaging in the assessment of hepatic sinusoidal obstruction syndrome in a mouse model

BACKGROUND Neoadjuvant chemotherapy can cause hepatic sinusoidal obstruction syndrome(SOS)in patients with colorectal cancer liver metastases and increases posto-perative morbidity and mortality.AIM To evaluate T1 mapping based on gadoxetic acid-enhanced magnetic resonance imaging(MRI)for diagnosis of hepatic SOS induced by monocrotaline.METHODS Twenty-four mice were divided into control(n=10)and experimental(n=14)groups.The experimental groups were injected with monocrotaline 2 or 6 days before MRI.MRI parameters were:T1 relaxation time before enhancement;T1 relaxation time 20 minutes after enhancement(T_(1post));a reduction in T1 relaxation time(△T_(1)%);and first enhancement slope percentage of the liver parenchyma(ESP).Albumin and bilirubin score was determined.Histological results served as a reference.Liver parenchyma samples from the control and experimental groups were analyzed by western blotting,and organic anion transporter polypeptide 1(OATP1)was measured.RESULTS T_(1post),△T_(1)%,and ESP of the liver parenchyma were significantly different between two groups(all P<0.001)and significantly correlated with the total histological score of hepatic SOS(r=-0.70,0.68 and 0.79;P<0.001).△T_(1)%and ESP were positively correlated with OATP1 levels(r=0.82,0.85;P<0.001),whereas T_(1post) had a negative correlation with OATP1 levels(r=-0.83;P<0.001).INTRODUCTION Hepatic sinusoidal obstruction syndrome(SOS)is also known as hepatic veno-occlusive disease of the liver[1].The main pathological feature of hepatic SOS is damage to liver terminal vessels,and the clinical symptoms of it include ascites and abdominal pain[2].It was first proposed in 1979 as an early complication of hematopoietic stem cell transplantation[3].The prevalence ranges from 5%to 60%,and hepatic SOS is a potentially severe complication and can even lead to death in severe cases[4].Recently,systemic neoadjuvant chemotherapy became widely regarded as one of the causes hepatic SOS in the patients with advanced metastatic colorectal cancer[5,6],especially those were treated with oxaliplatin[7,8].Oxaliplatin-based preoperative chemotherapy is used for patients with colorectal liver metastases as the standard regimen[8,9],because it could improve tumor resection outcome by shrinking the metastatic sites and reducing recurrence rate[10].Nevertheless,chemotherapy-induced hepatic SOS has been associated with a higher risk of postresection morbidity[11],such as intraoperative bleeding,intraoperative transfusions,and postoperative liver failure[12].Therefore,it is important to detect and diagnose of hepatic SOS timely.Currently,the gold standard is still based on liver biopsy[13],but it is an invasive procedure and has several limitations and complications,such as hemorrhage[14].A noninvasive diagnostic modality is needed for the assessment of hepatic SOS.Some noninvasive tools have been used for diagnosis of hepatic SOS.Researchers have utilized a preoperative platelet count and aspartate aminotransferase to platelet ratio index[15].In addition,some imaging methods such as shear wave ultrasonography,computed tomography,and gadoxetic acid-enhanced magnetic resonance imaging(MRI)have been promoted as useful methods for evaluation of hepatic SOS[16-18].Recent studies with monocrotaline(MCT)-treated rats were conducted to investigate diagnosis and prediction of severity of SOS.For example,intravoxel incoherent motion diffusion-weighted imaging,non-Gaussian diffusion models,and T1 rho quantification[19,20].The MCT-induced hepatic SOS animal model was reproducible,with a detailed pathological scoring criteria[21].Gadoxetic acid is a hepatocyte-specific contrast substance,which can provide parenchymal contrast in the hepato-biliary phase.It is reported that gadoxetic acid is absorbed into the liver parenchyma via organic anion transporter polypeptide 1(OATP1)on the hepatocyte membranes[22-24].Recently,several authors have described the feasibility of gadoxetic acid-enhanced MRI for the diagnosis of oxaliplatin-induced hepatic SOS[25].They mainly diagnosed hepatic SOS based on the signal intensity of the hepatobiliary specific phase.However,there were several limitations due to the inconsistency between signal intensity of the liver parenchyma and the concentration of contrast agent for evaluation of the degree of hepatic SOS[26].Therefore,we measured T1 relaxation time on parametric mapping because it is linearly related to the concentration of the contrast agent and is not affected by other factors[27].Yang et al[28]demonstrated T1 mapping on gadoxetic acid-enhanced MRI for the assessment of oxaliplatin-induced liver injury in a C57BL/6 mouse model.However,the main pathological changes in their model were hepatocyte degeneration and fibrosis.Therefore,we aimed to explore the effectiveness of T1 mapping based on gadoxetic acid-enhanced MRI for the diagnosis of hepatic SOS in a C57BL/6 mouse model,as well as a possible relation between OATP1 Levels and MRI parameters.