Cholelithiasis is one of the most common diseases of the digestive system,and the accurate preoperative diagnosis of cholelithiasis is important to guiding treatment and improving prognosis.Dual-energy CT based on material decomposition and post-processing techniques can generate virtual monoenergetic images,virtual noncontrast images,calcium-and fat-based material decomposition images and Rho/Z images which are helpful for detecting isoattenuating gallstones,and offer objective evidence for diagnosing gallstone disease and its complications.This article reviews the principle of dual-energy CT and its progress in cholelithiasis.

Cholelithiasis is one of the most common diseases of the digestive system,and the accurate preoperative diagnosis of cholelithiasis is important to guiding treatment and improving prognosis.Dual-energy CT based on material decomposition and post-processing techniques can generate virtual monoenergetic images,virtual noncontrast images,calcium-and fat-based material decomposition images and Rho/Z images which are helpful for detecting isoattenuating gallstones,and offer objective evidence for diagnosing gallstone disease and its complications.This article reviews the principle of dual-energy CT and its progress in cholelithiasis.

Purpose To explore the imaging features and clinical pathology characteristics of extraskeletal Ewing sarcoma(EES).Materials and Methods The clinical and imaging data and pathological findings of 14 patients with EES confirmed by operation and pathology were retrospectively analyzed.CT examination was performed in 7 cases(including 5 enhanced)and MRI was performed on 9 cases(including 8 enhanced).Results The anatomic locations of the 14 patients included paraspinal area(n=3),mediastinum(n=1),right supraclavicular(n=1),left thigh(n=1),left parapubic region(n=1),retroperitoneal(n=1),pelvic cavity(n=1),prostate(n=2),left kidney(n=1),pancreas(n=1)and liver(n=1).All 14 cases of EES showed single solid mass,13 cases were lumpy,and the maximum diameter of the lesion ranged from 48.0 mm to 180.0 mm.8 cases showed uneven density or signal,cystic degeneration and necrosis was seen.one case had calcification.After enhancement,8 cases showed uneven enhancement,12 cases showed severe or moderate enhancement.10 cases were irregular in shape,11 cases had peripheral organ or tissue invasion,3 cases had no peripheral organ or tissue invasion.5 cases had peripheral bone destruction.One case had left renal vein and inferior vena cava tumor thrombus and thrombus,iliac vein thrombus.Conclusion The clinical symptoms of EES are nonspecific.The imaging manifestations of EES are mostly massive solid masses in extraosseous soft tissue,with uneven density or signal,irregular shape,often accompanied by cystic degeneration and necrosis and invasion of surrounding organs or tissues.Imaging is of great value in preoperative diagnosis,clinical staging,treatment and efficacy evaluation.

Purpose To evaluate the diagnostic accuracy of abdominal plain scan and contrast-enhanced multi-slice CT after orally diluted iodide in time segment(Post-ODI ANCCE-MSCT)for gastrointestinal fistula(GIF)secondary to acute pancreatitis(AP).Materials and Methods A total of 108 patients with late AP in the prospective and continuously collected database of Hunan Provincial People's Hospital from January 2017 to December 2022 were retrospectively extracted.Their demographic information and clinical features were recorded and GIF were screened by Post-ODI ANCCE-MSCT.The comprehensive clinical diagnosis results within 5 days thereafter were used as reference standards.The sensitivity,specificity,positive predictive value,negative predictive value and accuracy of Post-ODI ANCCE-MSCT for diagnosing GIF secondary to AP were calculated using a four-cell table,and the consistency of the two methods was evaluated by Kappa test and McNemar's test.Results Sensitivity was 91.5%(95%CI 78.7%-97.2%),specificity was 98.4%(95%CI 90.0%-99.9%),positive predictive value was 97.7%(95%CI 86.5%-99.9%),negative predictive value was 93.8%(95%CI 84.0%-98.0%),and the accuracy was 95.4%(95%CI 91.4%-99.3%),respectively.The Kappa value was 0.905,and P value was 0.375 via McNemar's test.Conclusion Post-ODI ANCCE-MSCT can diagnose GIF secondary to AP in a simple,non-invasive,rapid and accurate way,and provide earlier,more accurate and reliable image basis for clinical diagnosis and treatment.

To determine the value of radiomics in identifying lymph node (LN) metastasis in patients with rectal nonmucinous adenocarcinoma.
 Methods: Imaging data of 91 patients were retrospectively analyzed (61 in the training set and 30 in the test set). A total of 1 301 radiomics features were extracted from high-resolution T2-weighted images of the whole primary tumor. The least absolute shrinkage and selection operator (LASSO) logistic regression was performed to choose the optimal features and construct a radiomics classifier in the training set. Its discrimination performance was compared with that of morphological criteria by receiver operating characteristic (ROC) curve analysis, which was validated in the test set.
 Results: The radiomics classifier combined with five key features was significantly associated with LN metastasis, which distinguished LN metastasis with an area under curve (AUC) at 0.874 (95% CI 0.787 to 0.960) in the training set, and the performance was similar in the test set (AUC 0.878, 95% CI 0.727 to 1.000). The AUCs according to the morphological criteria in the training set and test set were 0.619 (95% CI 0.487 to 0.752) and 0.556 (95% CI 0.355 to 0.756), respectively. Discrimination of the radiomics classifier was superior to that of morphological criteria in both the two datasets (both P <0.05).
 Conclusion: The radiomics classifier provides individualized risk estimation for LN metastasis in rectal nonmucinous adenocarcinoma patients and it has the advantage over the morphological criteria.
Adenocarcinoma ; Humans ; Lymph Nodes ; Lymphatic Metastasis ; Rectal Neoplasms ; Retrospective Studies

To analyze the CT features of solid pseudopapillary tumor of pancreas (SPTP), and correlation with the pathological findings of the disease so as to improve the diagnostic abilities, the CT images and the clinical manifestations, we retrospectively analyzed the pathological materials of 23 cases with surgery and pathology proved SPTP. In the 23 patients, 21 cases were female (91.3%) and 2 were male (8.7%). The most common symptom was abdominal discomfort with dull pain in 12 patients (52.2%). Others included the pancreatic mass that was detected incidentally during physical examination in 9 patients (39.1%), nausea/vomiting in 2 patients (8.7%). And 1 case of female patients had 2 lesions. In the 24 tumors, 6 cases were located at the head (25.0%), 3 were at neck (12.5%), 8 cases were at body (33.3%), and 7 cases were at tail of pancreas respectively (29.2%). The long-axis diameter ranged from 2.1 cm to 20.1 cm (mean 6.4 cm). 9 tumors were mostly solid component (37.5%), 10 tumors were contained similar proportion of solid and cystic part (41.7%), and mainly cystic components in 5 tumors (20.8%). In 9 of the 23 patients, calcification was found in the tumor (39.1%). In 2 of the 23 patients, bleeding was seen in the mass (8.7%). The dilation of intrahepatic bile duct was found in 1 patient (8.7%). Liver metastasis was showed in one patient (8.7%). On post-contrast CT scan, solid parts demonstrated mild enhancement at the arterial phase. At the portal phase, solid parts were enhanced continuously in all cases, and the enhancement degrees were lower than normal pancreatic tissue. The cystic parts of all lesions showed no enhancement. Pseudo papillary structure, hemorrhage, necrosis, or cystic degeneration were found in all patients by histological study. In a word, SPTP has comparatively characteristic CT imaging features consistent with histological features, when combined with clinical manifestations, could be correctly diagnosed and differentially diagnosed.
Bile Ducts, Intrahepatic ; Calcinosis ; diagnostic imaging ; Female ; Humans ; Liver Neoplasms ; secondary ; Male ; Pancreas ; diagnostic imaging ; pathology ; Pancreatic Neoplasms ; diagnostic imaging ; pathology ; Retrospective Studies ; Tomography, X-Ray Computed