A synthetic diagnostics platform for microwave imaging diagnostics in tokamaks

Interpreting experimental diagnostics data in tokamaks,while considering non-ideal effects,is challenging due to the complexity of plasmas.To address this challenge,a general synthetic diagnostics(GSD)platform has been established that facilitates microwave imaging reflectometry and electron cyclotron emission imaging.This platform utilizes plasma profiles as input and incorporates the finite-difference time domain,ray tracing and the radiative transfer equation to calculate the propagation of plasma spontaneous radiation and the external electromagnetic field in plasmas.Benchmark tests for classical cases have been conducted to verify the accuracy of every core module in the GSD platform.Finally,2D imaging of a typical electron temperature distribution is reproduced by this platform and the results are consistent with the given real experimental data.This platform also has the potential to be extended to 3D electromagnetic field simulations and other microwave diagnostics such as cross-polarization scattering.

Portal hypertension: Imaging of portosystemic collateral pathways and associated image-guided therapy

Portal hypertension is a common clinical syndrome, defined by a pathologic increase in the portal venous pressure. Increased resistance to portal blood flow, the primary factor in the pathophysiology of portal hypertension, is in part due to morphological changes occurring in chronic liver diseases. This results in rerouting of blood flow away from the liver through collateral pathways to low-pressure systemic veins. Through a variety of computed tomographic, sonographic, magnetic resonance imaging and angiographic examples, this article discusses the appearances and prevalence of both common and less common portosystemic collateral channels in the thorax and abdomen. A brief overview of established interventional radiologic techniques for treatment of portal hypertension will also be provided. Awareness of the various imaging manifestations of portal hypertension can be helpful for assessing overall prognosis and planning proper management.

Explainable Conformer Network for Detection of COVID-19 Pneumonia from Chest CT Scan: From Concepts toward Clinical Explainability

The early implementation of treatment therapies necessitates the swift and precise identification of COVID-19 pneumonia by the analysis of chest CT scans.This study aims to investigate the indispensable need for precise and interpretable diagnostic tools for improving clinical decision-making for COVID-19 diagnosis.This paper proposes a novel deep learning approach,called Conformer Network,for explainable discrimination of viral pneumonia depending on the lung Region of Infections(ROI)within a single modality radiographic CT scan.Firstly,an efficient U-shaped transformer network is integrated for lung image segmentation.Then,a robust transfer learning technique is introduced to design a robust feature extractor based on pre-trained lightweight Big Transfer(BiT-L)and finetuned on medical data to effectively learn the patterns of infection in the input image.Secondly,this work presents a visual explanation method to guarantee clinical explainability for decisions made by Conformer Network.Experimental evaluation of real-world CT data demonstrated that the diagnostic accuracy of ourmodel outperforms cutting-edge studies with statistical significance.The Conformer Network achieves 97.40% of detection accuracy under cross-validation settings.Our model not only achieves high sensitivity and specificity but also affords visualizations of salient features contributing to each classification decision,enhancing the overall transparency and trustworthiness of our model.The findings provide obvious implications for the ability of our model to empower clinical staff by generating transparent intuitions about the features driving diagnostic decisions.

Mediastinal emphysema in the context of perforated gastric ulcer

In the context of mediastinal emphysema/pneumomediastinum,the main aetiologies are associated with oesophageal perforation,lung pathology or post head and neck surgery related.The main way to differentiate the pathologies would be through Computed Tomographic Imaging of the Thorax and abdomen with oral and intravenous contrast in the context of triple phase imaging.The causes of pneumomediastinum should be differentiated between traumatic and non-traumatic.Oesophageal perforation(Boerhaave syndrome)is associated with Mackler’s triad in upto 50%of patients(severe retrosternal chest pain,pneumomediastinum,mediastinitis).Whereas in cases of lung pathology this can be associated with pneumothorax and pleural effusion.

Radiographic Equipment and Accessories as a Potential Source of Nosocomial Infection

Background: Nosocomial infections have become a major challenge in healthcare facilities as they affect the quality of medical care. Radiological imaging plays a crucial role in medical diagnosis. However, the equipment and accessories used increase the risk of transmission of nosocomial bacteria. Objective: This study aims to reveal the extent and nature of microbiological contamination in four hospital diagnostic imaging departments to determine their potential role in the spread of nosocomial bacteria and to evaluate the effectiveness of routine daily disinfection practices in controlling microorganisms in diagnostic imaging departments. Methods & Results: In each department, swabs were taken from the surfaces of selected parts of the equipment and accessories three times a day (early morning, noon, and evening) for five consecutive days. Bacteria were isolated from 65 swabs (36.1% of all samples). The bacteria were isolated 3 times (4.6%) in the morning, 16 times (24.6%) at midday, and 46 times (70.7%) in the evening. The bacteria isolated were Escherichia coli (isolated 34 times;52.3%), Staphylococcus aureus (20 times;30.8%), Staphylococcus epidermidis (6 times;9.3%), and Klebsiella species (5 times;7.7%). Discussion & Conclusion: Findings demonstrated that radiology equipment and accessories are not free of bacteria and further improvements in the sterilization and disinfection of radiology equipment and accessories are needed to protect staff and patients from nosocomial infections.

Radiomics for the detection of microvascular invasion in hepatocellular carcinoma

Hepatocellular carcinoma(HCC)is the most common primary liver cancer,accounting for about 90%of liver cancer cases.It is currently the fifth most common cancer in the world and the third leading cause of cancer-related mortality.Moreover,recurrence of HCC is common.Microvascular invasion(MVI)is a major factor associated with recurrence in postoperative HCC.It is difficult to evaluate MVI using traditional imaging modalities.Currently,MVI is assessed primarily through pathological and immunohistochemical analyses of postoperative tissue samples.Needle biopsy is the primary method used to confirm MVI diagnosis before surgery.As the puncture specimens represent just a small part of the tumor,and given the heterogeneity of HCC,biopsy samples may yield false-negative results.Radiomics,an emerging,powerful,and non-invasive tool based on various imaging modalities,such as computed tomography,magnetic resonance imaging,ultrasound,and positron emission tomography,can predict the HCC-MVI status preoperatively by delineating the tumor and/or the regions at a certain distance from the surface of the tumor to extract the image features.Although positive results have been reported for radiomics,its drawbacks have limited its clinical translation.This article reviews the application of radiomics,based on various imaging modalities,in preoperative evaluation of HCC-MVI and explores future research directions that facilitate its clinical translation.

Radiomics approach for preoperative identification of stages Ⅰ-Ⅱand Ⅲ-Ⅳ of esophageal cancer

Objective： To predict preoperative staging using a radiomics approach based on computed tomography （CT）images of patients with esophageal squamous cell carcinoma （ESCC）.Methods： This retrospective study included 154 patients （primary cohort： n： t 14; validation cohort： n：40） withpathologically confirmed ESCC. All patients underwent a preoperative CT scan from the neck to abdomen. Highthroughput and quantitative radiomics features were extracted from the CT images for each patient. A radiomicssignature was constructed using the least absolute shrinkage and selection operator （Lasso）. Associations betweenradiomics signature, tumor volume and ESCC staging were explored. Diagnostic performance of radiomicsapproach and tumor volume for discriminating between stages Ⅰ-Ⅱand Ⅲ-Ⅳ was evaluated and compared usingthe receiver operating characteristics （ROC） curves and net reclassification improvement （NRI）.Results= A total of 9,790 radiomics features were extracted. Ten features were selected to build a radiomicssignature after feature dimension reduction. The radiomics signature was significantly associated with ESCCstaging （P〈0.001）, and yielded a better performance for discrimination of early and advanced stage ESCC comparedto tumor volume in both the primary [area under the receiver operating characteristic curve （AUC）： 0.795 vs. 0.694,P=0.003; NRI=0.424）] and validation cohorts （AUC： 0.762 vs. 0.624, P=0.035; NRI=0.834）.Conclusions： The quantitative approach has the potential to identify stage Ⅰ-Ⅱand Ⅲ-Ⅳ ESCC beforetreatment.

Confocal laser endomicroscopy in the “in vivo” histological diagnosis of the gastrointestinal tract

Recent technological advances in miniaturization have allowed for a confocal scanning microscope to be integrated into a conventional flexible endoscope,or into trans-endoscopic probes,a technique now known as confocal endomicroscopy or confocal laser endomicroscopy.This newly-developed technology has enabled endoscopists to collect real-time in vivo histological images or "virtual biopsies" of the gastrointestinal mucosa during endoscopy,and has stimulated significant interest in the application of this technique in clinical gastroenterology.This review aims to evaluate the current data on the technical aspects and the utility of this new technology in clinical gastroenterology and its potential impact in the future,particularly in the screening or surveillance of gastrointestinal neoplasia.

Autoimmune pancreatitis:report of two cases and literature review

BACKGROUND: Autoimmune pancreatitis (All?) is a unique chronic inflammation of the pancreas in which autoimmune mechanisms are involved in the pathogenesis. It is characterized by clinical, histopathological, radiographic, serologic and therapeutic features. Since it was first described in 1995, increasing numbers of AIP patients have been diagnosed. METHODS: In this study, the data from 2 patients with AIP who had elevation of serum immunoglobulin G, positive autoantibody, swelling of the pancreas and narrowing of the main pancreatic duct on imaging were analyzed retrospectively. RESULTS: With the initial diagnosis of AIP, both patients underwent regular prednisone therapy, which was initiated at a dose of 40 mg per day with a tapering schedule of 5 mg every 2 weeks. The patients responded very well to treatment with prednisone. CONCLUSIONS: AIP is a relatively new disease entity. Although it is diagnosed by distinct characteristics of the clinical, radiologic, histopathologic, and serologic findings, many questions require further clarification, including its relationship to other autoimmune diseases and misdiagnosis as pancreaticobiliary malignancies.

Current update on molecular cytogenetics, diagnosis and management of gastrointestinal stromal tumors

Gastrointestinal stromal tumors(GISTs)are the most common mesenchymal tumors of the gastrointestinal(GI)tract and are thought to arise from precursors of the interstitial cells of Cajal.GISTs can arise anywhere in the GI tract,but most commonly originate from the stomach and small intestine.The majority of GISTs occur as a result of activating mutations in two receptor protein tyrosine kinases:KIT and/or platelet-derived growth factor receptor-α.Mutational analyses allow for predicting patient prognosis and treatment response.Clinical presentations can vary from no symptoms,typical in the case of small incidentally found tumors,to GI bleeding,abdominal discomfort,and ulcer-related symptoms when the tumor is enlarged.Imaging plays a critical role in the diagnosis and management of these tumors with multiphasic computed tomography serving as the imaging modality of choice.Magnetic resonance imaging and positron emission tomography-computed tomography can serve as imaging adjuncts in lesion characterization,especially with liver metastases,and subsequent staging and assessment for treatment response or recurrence.Surgical resection is the preferred management for small GISTs,while tyrosine kinase inhibitors−imatinib mesylate and sunitinib malate−serve as crucial molecular-targeted therapies for locally advanced and metastatic GISTs.This review article highlights the clinical presentation,pathology and molecular cytogenetics,imaging features,and current management of GISTs.

Imaging features of intraductal papillary mucinous neoplasms of the pancreas in multi-detector row computed tomography

AIM:To retrospectively evaluate the imaging features of pancreatic intraductal papillary mucinous neoplasms (IPMNs) in multi-detector row computed tomography (MDCT).METHODS: A total of 20 patients with pathologically-confirmed intraductal papillary mucinous neoplasms (IPMNs) were included in this study. Axial MDCT images combined with CT angiography (CTA) and multiplanar volume reformations (MPVR) or curved reformations (CR) were preoperatively acquired. Two radiologists (Tan L and Wang DB) reviewed all the images in consensus using an interactive picture archiving and communication system. The disputes in readings were resolved through consultation with a third experienced radiologist (Chen KM). Finally, the findings and diagnoses were compared with the pathologic results.RESULTS: The pathological study revealed 12 malignant IPMNs and eight benign IPMNs. The diameters of the cystic lesions and main pancreatic ducts (MPDs) were significantly larger in malignant IPMNs compared with those of the benign IPMNs (P<0.05). The combined-type IPMNs had a higher rate of malignancy than the other two types of IPMNs (P<0.05). Tumors with mural nodules and thick septa had a significantly higher incidence of malignancy than tumors without these features (P<0.05). Communication of side-branch IPMNs with the MPD was present in nine cases at pathologic examination. Seven of them were identified from CTA and MPVR or CR images. From comparison with the pathological diagnosis, the sensitivity, specificity, and accuracy of MDCT in characterizing the malignancy of IPMN of the pancreas were determined to be 100%, 87.5% and 95%, respectively.CONCLUSION: MDCT with CTA and MPVR or CR techniques can elucidate the imaging features of IPMNs and help predict the malignancy of these tumors.

Comparison of imaging-based and pathological dimensions in pancreatic neuroendocrine tumors

AIM To establish the ability of magnetic resonance(MR) and computer tomography(CT) to predict pathologic dimensions of pancreatic neuroendocrine tumors(Pan NET) in a caseload of a tertiary referral center.METHODS Patients submitted to surgery for Pan NET at the Surgical Unit of the Pancreas Institute with at least 1 preoperative imaging examination(MR or CT scan) from January 2005 to December 2015 were included and data retrospectively collected. Exclusion criteria were: multifocal lesions, genetic syndromes, microadenomas or mixed tumors, metastatic disease and neoadjuvant therapy. Bland-Altman(BA) and Mountain-Plot(MP) statistics were used to compare size measured by each modality with the pathology size. Passing-Bablok(PB) regression analysis was used to check the agreement between MR and CT.RESULTS Our study population consisted of 292 patients. Seventy-nine(27.1%) were functioning Pan NET. The mean biases were 0.17 ± 7.99 mm, 1 ± 8.51 mm and 0.23 ± 9 mm, 1.2 ± 9.8 mm for MR and CT, considering the overall population and the subgroup of non-functioning-Pan NET, respectively. Limits of agreement(LOA) included the vast majority of observations, indicating a good agreement between imaging and pathology. The MP further confirmed this finding and showed that the two methods are unbiased with respect to each other. Considering ≤ 2 cm non-functioning-Pan NET, no statistical significance was found in the size estimation rate of MR and CT(P = 0.433). PBR analysis did not reveal significant differences between MR, CT and pathology.CONCLUSION MR and CT scan are accurate and interchangeable imaging techniques in predicting pathologic dimensions of Pan NET.

Potential role of imaging in assessing harmful effects on spermatogenesis in adult testes with varicocele

Varicocele is characterized by an abnormal dilatation and retrograde blood flow in the spermatic veins. Varicocele is the leading correctable cause of male infertility. Although it is highly prevalent in infertile men, it is also observed in individuals with normal fertility. Determining which men are negatively affected by varicocele would enable clinicians to better select those men who will benefit from treatment. To assess the functional status of the testes in men with varicocele, color Doppler sonographic parameters were evaluated. Testicular arterial blood flow was significantly reduced in men with varicocele, reflecting an impairment of spermatogenesis. An improvement in the testicular blood supply was found after varicocelectomy on spectral Doppler analysis. Testicular contrast harmonic imaging and elastography might improve our knowledge about the influence of varicocele on intratesticular microcirculation and tissue stiffness, respectively, providing possible information on the early damage of testicular structure by varicocele. Magnetic resonance imaging(MRI), with measurement of apparent diffusion coefficient has been used to assess the degree of testicular dysfunction and to evaluate the effectiveness of varicocele repair. Large prospective studies are needed to validate the possible role of functional sonography and MRI in the assessment of early defects of spermatogenesis in testes with varicocele.

Enhancement parameters of contrast-enhanced computed tomography for pancreatic ductal adenocarcinoma: Correlation with pathologic grading

BACKGROUND Pancreatic ductal adenocarcinoma(PDA)is a malignancy with a high mortality rate and short survival time.The conventional computed tomography(CT)has been worldwide used as a modality for diagnosis of PDA,as CT enhancement pattern has been thought to be related to tumor angiogenesis and pathologic grade of PDA.AIM To evaluate the relationship between the pathologic grade of pancreatic ductal adenocarcinoma and the enhancement parameters of contrast-enhanced CT.METHODS In this retrospective study,42 patients(Age,mean±SD:62.43±11.42 years)with PDA who underwent surgery after preoperative CT were selected.Two radiologists evaluated the CT images and calculated the value of attenuation at the aorta in the arterial phase and the pancreatic phase(VAarterial and VApancreatic)and of the tumor(VTarterial and VTpancreatic)by finding out four regions of interest.Ratio between the tumor and the aorta enhancement on the arterial phase and the pancreatic phase(TARarterial and TARpancreatic)was figured out through dividing VT arterial by VAarterial and VTpancreatic by VApancreatic.Tumor-to-aortic enhancement fraction(TAF)was expressed as the ratio of the difference between attenuation of the tumor on arterial and parenchymal images to that between attenuation of the aorta on arterial and pancreatic images.The Kruskal-Wallis analysis of variance and Mann-Whitney U test for statistical analysis were used.RESULTS Forty-two PDAs(23 men and 19 women)were divided into three groups:Welldifferentiated(n=13),moderately differentiated(n=21),and poorly differentiated(n=8).TAF differed significantly between the three groups(P=0.034)but TARarterial(P=0.164)and TARpancreatic(P=0.339)did not.The median value of TAF for poorly differentiated PDAs(0.1011;95%CI:0.01100-0.1796)was significantly higher than that for well-differentiated PDAs(0.1941;95%CI:0.1463-0.3194).CONCLUSION Calculation of TAF might be useful in predicting the pathologic grade of PDA.

Pancreatitis in pregnancy: etiology, diagnosis, treatment, and outcomes

BACKGROUND：Acute pancreatitis in pregnancy is a rare and dangerous disease.This study aimed to examine the etiology,treatment,and outcomes of pancreatitis in pregnancy.METHOD：A total of 25 pregnant patients diagnosed with pancreatitis during the period of 1994 and 2014 was analyzed retrospectively.RESULTS：The pregnant patients were diagnosed with pancreatitis during a period of 21 years.Most（60%）of the patients were diagnosed with pancreatitis in the third trimester.The mean age of the patients at presentation was 25.7 years,with a mean gestational age of 24.4 weeks.Abdominal pain occurred in most patients and vomiting in one patient was associated hyperemesis gravidarum.The common cause of the disease was gallstone-related（56%）,followed by alcohol-related（16%）,post-ERCP（4%）,hereditary（4%）and undetermined conditions（20%）.The level of triglycerides was minimally high in three patients.ERCP and wire-guided sphincterotomy were performed in 6（43%）of 14 patients with gallstone-related pancreatitis and elevated liver enzymes with no complications.Most（84%）of the patients underwent a full-term,vaginal delivery.There was no difference in either maternal or fetal outcomes after ERCP.CONCLUSIONS：Acute pancreatitis is rare in pregnancy,occurring most commonly in the third trimester,and gallstones are the most common cause.When laparoscopic cholecystectomy is not feasible and a common bile duct stone is highly suspected on imaging,endoscopic sphincterotomy or stenting may help to prevent recurrence and postpone cholecystectomy until after delivery.

Meckel's diverticulum masked by a long period of intermittent recurrent subocclusive episodes

Meckel's diverticulum(MD) is the most frequent congenital abnormality of the small bowel and it is often diff icult to diagnose.It is usually asymptomatic but approximately 4% are symptomatic with complications such as bleeding,intestinal obstruction,and inflammation.The authors report a case of a 7-year-old boy with a one-year history of recurrent periumbilical colicky pain with associated alimentary vomiting,symptoms erroneously related to a cyclic vomiting syndrome but not to MD.The clinical features and the differential diagnostic methods employed for diagnosis of MD are discussed.

Clinical value of contrast-enhanced ultrasound in early diagnosis of small hepatocellular carcinoma (≤ 2 cm)

BACKGROUND Hepatocellular carcinoma(HCC)is the most common type of primary liver malignancy.Contrast-enhanced ultrasound(CEUS)uses contrast microbubbles during ultrasound,allowing the detection and characterization of malignant focal liver lesions with much higher diagnostic accuracy than conventional ultrasound;however,there are few reports focusing on the pattern of enhancement of CEUS for the diagnosis of HCC smaller than 2 cm.AIM To investigate the clinical value of CEUS in the early detection of small HCC with high risk factors.METHODS A total of 395 patients with 632 nodules at high risk of HCC,who underwent regular follow-up at Xuhui Dahua Hospital from January 2007 to December 2021,were retrospectively examined.Conventional ultrasonography combined with CEUS was adopted to analyze the echo,size,location,and enhancement characteristics of benign and malignant nodules,as well as the enhancement methods for HCC with different diameters.RESULTS The follow-up rate and duration were 92.15%(364/395)and 51.28±45.09 mo,respectively.Conventional ultrasonography combined with CEUS revealed 65(11.80%)nodules with a follow-up diagnosis of HCC,19(3.45%)dysplastic nodules,and 467(84.75%)benign cirrhotic hyperplastic nodules.Among 65 cases of confirmed HCC,40(61.54%)were transformed from hypoechoic nodules,9(13.85%)from hyperechoic nodules,and the remaining 16(24.62%)from isoechoic nodules.Significant differences in CEUS characteristics were found among cirrhotic nodules,dysplastic nodules,and HCC nodules at each phase.Significant differences in the enhancement mode were observed between nodules≤1 cm and those 1–2 cm.The smaller the HCC nodule,the later the contrast agent began to flush and the longer the duration of contrast enhancement.CONCLUSION Conventional ultrasonography combined with CEUS could identify small HCC and help monitor patients with an early diagnosis of HCC.Significant differences in the enhancement mode are noted between nodules≤1 cm and those 1–2 cm.

Radiological prognosticators of hepatocellular carcinoma treated by hepatectomy

BACKGROUND: Hepatectomy is the main curative treatment for hepatocellular carcinoma (HCC), but postoperative long- term survival is poor. Preoperative radiological features of HCC displayed by computed tomography or magnetic resonance imaging could serve as additional prognostic factors. This study aimed to identify preoperative radiological features of HCC that may be of prognostic significance in hepatectomy. METHODS: Ninety-two patients who underwent hepatectomy for HCC were included in this study. Preoperative radiological features including tumor number, size, location (peripheral, middle, central), portal vein invasion, hepatic vein invasion, and presence of pseudo-capsule were analyzed in relation to survival. RESULTS: With a median follow-up period of 41.7 months, the 1-, 3- and 5-year overall survival rates were 85%, 65% and 58%, respectively. Univariate analysis showed that portal vein invasion and absence of pseudo-capsule were significant prognostic factors for overall survival, while all the examined radiological features were prognostic factors for disease-free survival. Multivariate analysis for overall survival found no significant factor. On multivariate analysis for disease-free survival, patients who had tumors with portal vein invasion had poorer survival with a hazard ratio of 2.26 (95% CI, 1.05-4.91; P=0.038) and patients with single nodular HCC or pseudo-capsulated HCC had better survival with a hazard ratio of 0.50 (95% CI, 0.27-0.94; P=0.032) and 0.38 (95% CI, 0.14-0.99; P=0.048), respectively. CONCLUSIONS: Demonstrable pseudo-capsule of HCC and solitary HCC on imaging and absence of portal vein invasionare features associated with better disease-free survival after hepatectomy. These features may guide treatment planning for HCC.

Reversible lesions in the brain parenchyma in Wilson's disease confirmed by magnetic resonance imaging:earlier administration of chelating therapy can reduce the damage to the brain

The aim of this study was to evaluate the resolution of brain lesions in patients with Wilson’s disease during the long-term chelating therapy using magnetic resonance imaging and a possible signiifcance of the time latency between the initial symptoms of the disease and the introduction of this therapy. Initial magnetic resonance examination was performed in 37 patients with proven neurological form of Wilson’s disease with cerebellar, parkinsonian and dystonic presentation. Magnetic resonance reexamination was done 5.7 ± 1.3 years later in 14 patients. Patients were divided into： group A, where chelating therapy was initiated 〈 24 months from the ifrst symp-toms and group B, where the therapy started≥ 24 months after the initial symptoms. Symmetry of the lesions was seen in 100% of patients. There was a signiifcant difference between groups A and B regarding complete resolution of brain stem and putaminal lesions （P= 0.005 andP=0.024, respectively）. If the correct diagnosis and adequate treatment are not established less than 24 months after onset of the symptoms, irreversible lesions in the brain parenchyma could be ex-pected. Signal abnormalities on magnetic resonance imaging might therefore, at least in the early stages, represent reversible myelinolisis or cytotoxic edema associated with copper toxicity.

Prognostic value of preoperative enhanced computed tomography as a quantitative imaging biomarker in pancreatic cancer

BACKGROUND Pancreatic ductal adenocarcinoma(PDAC)is one of the most lethal malignancies with high mortality and short survival time.Computed tomography(CT)plays an important role in the diagnosis,staging and treatment of pancreatic tumour.Pancreatic cancer generally shows a low enhancement pattern compared with normal pancreatic tissue.AIM To analyse whether preoperative enhanced CT could be used to predict postoperative overall survival in patients with PDAC.METHODS Sixty-seven patients with PDAC undergoing pancreatic resection were enrolled retrospectively.All patients underwent preoperative unenhanced and enhanced CT examination,the CT values of which were measured.The ratio of the preoperative CT value increase from the nonenhancement phase to the portal venous phase between pancreatic tumour and normal pancreatic tissue was calculated.The cut-off value of ratios was obtained by the receiver operating characteristic(ROC)curve of the tumour relative enhancement ratio(TRER),according to which patients were divided into low-and high-enhancement groups.Univariate and multivariate analyses were performed using Cox regression based on TRER grouping.Finally,the correlation between TRER and clinicopathological characteristics was analysed.RESULTS The area under the curve of the ROC curve was 0.768(P<0.05),and the cut-off value of the ROC curve was calculated as 0.7.TRER≤0.7 was defined as the low-enhancement group,and TRER>0.7 was defined as the high-enhancement group.According to the TRER grouping,the Kaplan-Meier survival curve analysis results showed that the median survival(10.0 mo)with TRER≤0.7 was significantly shorter than that(22.0 mo)with TRER>0.7(P<0.05).In the univariate and multivariate analyses,the prognosis of patients with TRER≤0.7 was significantly worse than that of patients with TRER>0.7(P<0.05).Our results demonstrated that patients in the low TRER group were more likely to have higher American Joint Committee on Cancer stage,tumour stage and lymph node stage(all P<0.05),and TRER was significantly negatively correlated with tumour size(P<0.05).CONCLUSION TRER≤0.7 in patients with PDAC may represent a tumour with higher clinical stage and result in a shorter overall survival.