Predicting Microvascular Invasion in Hepatocellular Carcinoma Using CT-based Radiomics Model.

Background Prediction of microvascular invasion (MVI) may help determine treatment strategies for hepatocellular carcinoma (HCC). Purpose To develop a radiomics approach for predicting MVI status based on preoperative multiphase CT images and to identify MVI-associated differentially expressed genes. Materials and Methods Patients with pathologically proven HCC from May 2012 to September 2020 were retrospectively included from four medical centers. Radiomics features were extracted from tumors and peritumor regions on preoperative registration or subtraction CT images. In the training set, these features were used to build five radiomics models via logistic regression after feature reduction. The models were tested using internal and external test sets against a pathologic reference standard to calculate area under the receiver operating characteristic curve (AUC). The optimal AUC radiomics model and clinical-radiologic characteristics were combined to build the hybrid model. The log-rank test was used in the outcome cohort (Kunming center) to analyze early recurrence-free survival and overall survival based on high versus low model-derived score. RNA sequencing data from The Cancer Image Archive were used for gene expression analysis. Results A total of 773 patients (median age, 59 years; IQR, 49-64 years; 633 men) were divided into the training set (n = 334), internal test set (n = 142), external test set (n = 141), outcome cohort (n = 121), and RNA sequencing analysis set (n = 35). The AUCs from the radiomics and hybrid models, respectively, were 0.76 and 0.86 for the internal test set and 0.72 and 0.84 for the external test set. Early recurrence-free survival (P < .01) and overall survival (P < .007) can be categorized using the hybrid model. Differentially expressed genes in patients with findings positive for MVI were involved in glucose metabolism. Conclusion The hybrid model showed the best performance in prediction of MVI. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Summers in this issue.

The relationship between fasting blood glucose level and thromboembolism events in patients with non-valvular atrial fibrillation / 中华心血管病杂志

Objective: To explore the relationship between fasting blood glucose level and thromboembolism events in patients with non-valvular atrial fibrillation (NVAF). Methods: This was an observational study based on data from a multicenter, prospective Chinese atrial fibrillation registry cohort, which included 18 703 consecutive patients with atrial fibrillation (AF) in 31 hospitals in Beijing from August 2011 to December 2018. Patients were divided into 5 groups according to status of comorbid diabetes and fasting glucose levels at admission: normal blood glucose (normal glucose group), pre-diabetes group, strict glycemic control group, average glycemic control group and poor glycemic control group. Patients were followed up by telephone or outpatient service every 6 months. The primary follow-up endpoint was thromboembolic events, including ischemic stroke and systemic embolism. The secondary endpoint was the composite endpoint of cardiovascular death and thromboembolic events. Kaplan-Meier survival analysis and multifactorial Cox regression were used to analyze the correlation between fasting glucose levels and endpoint events. Results: The age of 18 703 patients with NVAF was (63.8±12.0) years, and there were 11 503 (61.5%) male patients. There were 11 877 patients (63.5%) in normal blood glucose group, 2 023 patients (10.8%)in pre-diabetes group, 1 131 patients (6.0%) in strict glycemic control group, 811 patients in average glycemic control group and 2 861 patients(4.3%) in poor glycemic control group. Of the 4 803 diabetic patients, 1 131 patients (23.5%) achieved strict glycemic control, of whom 328 (29.0%) were hypoglycemic (fasting blood glucose level<4.4 mmol/L at admission). During a mean follow-up of (51±23) months (up to 82 months), thromboembolic events were reported in 984 patients (5.3%). The survival curve analysis of Kaplan Meier showed that the incidence rates of thromboembolic events in normal glucose group, pre-diabetes group, strict glycemic control group, average glycemic control group and poor glycemic control group were 1.10/100, 1.41/100, 2.09/100, 1.46/100 and 1.71/100 person-years, respectively (χ²=53.0, log-rank P<0.001). The incidence rates of composite endpoint events were 1.86/100, 2.17/100, 4.08/100, 2.58/100, 3.16/100 person-years (χ²=72.3, log-rank P<0.001). The incidence of thromboembolic events and composite endpoint events in the other four groups were higher than that in the normal blood glucose group (P<0.001). Multivariate Cox regression analysis showed that compared with normal glucose group, the risk of thromboembolism increased in pre-diabetes group(HR=1.23, 95%CI 1.00-1.51, P=0.049), strict glycemic control group(HR=1.32, 95%CI 1.06-1.65, P=0.013) and poor glycemic control group(HR=1.26, 95%CI 1.01-1.58, P=0.044). Conclusion: Both high or low fasting glucose may be an independent risk factor for thromboembolic events in patients with NVAF.

Feasibility and safety of intracardiac ultrasound-assisted atrial septal puncture during radiofrequency ablation for atrial fibrillation / 中华心血管病杂志

Objective: To explore the feasibility and safety of intracardiac ultrasound-assisted atrial septal puncture (ASP) during radiofrequency ablation for atrial fibrillation. Methods: We enrolled 241 consecutive patients scheduled to radiofrequency ablation for atrial fibrillation in Beijing Anzhen Hospital from July to September 2020. Inclusion criteria: patients aged over 18 years with a clear electrocardiogram record of atrial fibrillation. Patients were divided into 2 groups: ASP with ultrasound-assisted X-ray (ultrasound group, n=123), ASP under X-ray alone (X-ray group, n=118). Clinical features of patients including age, sex, percent of paroxysmal atrial fibrillation, and repeat ablation, CHA2DS2-VASc score and past history (hypertension, diabetes mellitus, coronary artery disease, stroke/transient ischemic attack (TIA), valve diseases) and echocardiographic parameters (left atrial dimension, left ventricular ejection fraction, left ventricular end-diastolic dimension) were obtained and compared. The first-pass rate, radiation exposure time, duration of ASP, and complications of ASP were also compared between the two groups. Results: The age of patients in this cohort was (62.5±8.0) years, and the proportion of males was 57.0% (n=138). Among them, the proportion of paroxysmal atrial fibrillation was 56.0% (n=135), and the ratio of repeat ablation was 17.8% (n=43). Age, sex, percent of paroxysmal atrial fibrillation, history of hypertension, diabetes mellitus were similar between the two groups. The first-pass rate was significantly higher in the ultrasound group than in the X-ray group (94.3% (116/123) vs. 79.7% (94/118), P=0.001); the exposure time of X-ray was significantly shorter in the ultrasound group than in the X-ray group ((31.3±7.9) s vs. (124.8±35.7) s, P<0.001), while the duration of ASP was longer in the ultrasound group ((10.1±1.8) minutes vs. (8.2±1.3) minutes, P<0.001). In terms of complications, the incidence of puncture into the pericardium was lower in the ultrasound group (0 vs.3.4% (4/118), P=0.039); the rate of transient ST-segment elevation post ASP was similar between the ultrasound group and X-ray group (2.4% (3/123) vs. 1.7% (2/118), P=0.999). Conclusion: Intracardiac ultrasound-assisted atrial septal puncture can effectively improve the accuracy of atrial septal puncture, shorten the radiation exposure time, and reduce the complications related to atrial septal puncture.

Cytosine methylations in the promoter regions of genes involved in the cellular oxidation equilibrium pathways affect rice heat tolerance.

BACKGROUND: High temperatures, particularly at night, decrease rice yield and quality. As high nighttime temperatures (HNTs) become increasingly frequent due to climate change, it is imperative to develop rice crops that tolerate HNTs. DNA methylation may represent a potential avenue for HNT-tolerant rice strain development, as this mechanism regulates gene activity and cellular phenotype in response to adverse environmental conditions without changing the nucleotide sequence. RESULTS: After HNT exposure, the methylation patterns of cytosines in the CHH context differed noticeably between two coisogenic rice strains with significantly different levels in heat tolerance. Methylation differences between strains were primarily observed on successive cytosines in the promoter or downstream regions of transcription factors and transposon elements. In contrast to the heat-sensitive rice strain, the regions 358-359 bp and 2-60 bp downstream of two basal transcriptional factors (TFIID subunit 11 and mediator of RNA polymerase II transcription subunit 31, respectively) were fully demethylated in the heat-tolerant strain after HNT exposure. In the heat-tolerant strain, HNTs reversed the methylation patterns of successive cytosines in the promoter regions of various genes involved in abscisic acid (ABA)-related reactive oxygen species (ROS) equilibrium pathways, including the pentatricopeptide repeat domain gene PPR (LOC_Os07g28900) and the homeobox domain gene homeobox (LOC_Os01g19694). Indeed, PRR expression was inhibited in heat-sensitive rice strains, and the methylation rates of the cytosines in the promoter region of PRR were greater in heat-sensitive strains as compared to heat-tolerant strains. CONCLUSIONS: After HNT exposure, cytosines in the CHH context were more likely than cytosines in other contexts to be methylated differently between the heat-sensitive and heat-tolerant rice strains. Methylation in the promoter regions of the genes associated with ABA-related oxidation and ROS scavenging improved heat tolerance in rice. Our results help to clarify the molecular mechanisms underlying rice heat tolerance.

Statin Pretreatment Might Be Associated with Decreased Myocardial Injury After Ischemic Stroke.

BACKGROUND: Myocardial injury is a complication of stroke associated with unfavorable outcome, with the elevation of cardiac troponin as the most sensitive marker. In this study, we aimed at investigating the association between statin pretreatment and poststroke myocardial injury. METHODS: Six hundred seventy-one patients diagnosed as acute ischemic stroke were enrolled. According to the histories of statin pretreatment before stroke, patients were categorized into nonstatin (n = 474) and statin groups (n = 197), with the latter further divided into low-dosage, standard-dosage, and high-dosage subgroups according the dosages of statins. The level of troponin-T was tested and troponin-T level ≥14 ng/l was identified to indicate the presence of myocardial injury. The level of troponin-T and the prevalence of myocardial injury was compared between groups. Logistic regression was used to identify the effect of statin pretreatment for the presence of post-stroke myocardial injury. RESULTS: Statin users had lower levels of troponin-T after stroke, with the level of troponin-T being the lowest in the high-dosage subgroup. The results of logistic regression showed that statin pretreatment and high-dosage statin were independent protective factors for the elevation of troponin-T levels. CONCLUSIONS: Statin pretreatment might be associated with the decreased myocardial injury after ischemic stroke.

Structural, electronic, and optical properties of cubic formamidinium lead iodide perovskite: a first-principles investigation.

Hybrid organic-inorganic perovskites have been one of the most active areas of research into photovoltaic materials. Despite the extremely fast progress in this field, the electronic properties of formamidinium lead iodide perovskite (FAPbI3) that are key to its photovoltaic performance are relatively poorly understood when compared to those of methylammonium lead iodide (MAPbI3). In this study, first-principles total energy calculations based on density functional theory were used to investigate the favored orientation of FA. Different theoretical methods, with or without incorporation of spin-orbit coupling (SOC) effects, were used to study the structure, electronic properties, and charge-carrier effective mass. Also the SOC-induced Rashba k-dependent band splitting, density of states and optical properties are presented and discussed. These results are useful for understanding organic-inorganic lead trihalide perovskites and can inform the search for new materials and design rules.

Development of a Novel Multiparametric MRI Radiomic Nomogram for Preoperative Evaluation of Early Recurrence in Resectable Pancreatic Cancer.

BACKGROUND: In pancreatic cancer, methods to predict early recurrence (ER) and identify patients at increased risk of relapse are urgently required. PURPOSE: To develop a radiomic nomogram based on MR radiomics to stratify patients preoperatively and potentially improve clinical practice. STUDY TYPE: Retrospective. POPULATION: We enrolled 303 patients from two medical centers. Patients with a disease-free survival ≤12 months were assigned as the ER group (n = 130). Patients from the first medical center were divided into a training cohort (n = 123) and an internal validation cohort (n = 54). Patients from the second medical center were used as the external independent validation cohort (n = 126). FIELD STRENGTH/SEQUENCE: 3.0T axial T1 -weighted (T1 -w), T2 -weighted (T2 -w), contrast-enhanced T1 -weighted (CET1 -w). ASSESSMENT: ER was confirmed via imaging studies as MRI or CT. Risk factors, including clinical stage, CA19-9, and radiomic-related features of ER were assessed. In addition, to determine the intra- and interobserver reproducibility of radiomic features extraction, the intra- and interclass correlation coefficients (ICC) were calculated. STATISTICAL TESTS: The area under the receiver-operator characteristic (ROC) curve (AUC) was used to evaluate the predictive accuracy of the radiomic signature in both the training and test groups. The results of decision curve analysis (DCA) indicated that the radiomic nomogram achieved the most net benefit. RESULTS: The AUC values of ER evaluation for the radiomics signature were 0.80 (training cohort), 0.81 (internal validation cohort), and 0.78 (external validation cohort). Multivariate logistic analysis identified the radiomic signature, CA19-9 level, and clinical stage as independent parameters of ER. A radiomic nomogram was then developed incorporating the CA19-9 level and clinical stage. The AUC values for ER risk evaluation using the radiomic nomogram were 0.87 (training cohort), 0.88 (internal validation cohort), and 0.85 (external validation cohort). DATA CONCLUSION: The radiomic nomogram can effectively evaluate ER risks in patients with resectable pancreatic cancer preoperatively, which could potentially improve treatment strategies and facilitate personalized therapy in pancreatic cancer. LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2020;52:231-245.

Pancreatic neuroendocrine tumor: prediction of the tumor grade using magnetic resonance imaging findings and texture analysis with 3-T magnetic resonance.

PURPOSE: The purpose of this study was to evaluate the performance of magnetic resonance imaging (MRI) findings and texture parameters for prediction of the histopathologic grade of pancreatic neuroendocrine tumors (PNETs) with 3-T magnetic resonance. PATIENTS AND METHODS: PNETs are classified into Grade 1 (G1), Grade 2 (G2), and Grade 3 (G3) tumors based on the Ki-67 proliferation index and the mitotic activity. A total of 77 patients with pathologically confirmed PNETs met the inclusion criteria. Texture analysis (TA) was applied to T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) maps. Patient demographics, MRI findings, and texture parameters were compared among three different histopathologic subtypes by using Fisher's exact tests or Kruskal-Wallis test. Then, logistic regression analysis was adopted to predict tumor grades. ROC curves and AUCs were calculated to assess the diagnostic performance of MRI findings and texture parameters in prediction of tumor grades. RESULTS: There were 31 G1, 29 G2, and 17 G3 patients. Compared with G1, G2/G3 tumors showed higher frequencies of an ill-defined margin, a predominantly solid tumor type, local invasion or metastases, hypo-enhancement at the arterial phase, and restriction diffusion. Four T2-based (inverse difference moment, energy, correlation, and differenceEntropy) and five DWI-based (correlation, contrast, inverse difference moment, maxintensity, and entropy) TA parameters exhibited statistical significance among PNETs (P<0.001). The AUCs of six predicting models on T2WI and DWI ranged from 0.703-0.989. CONCLUSION: Our data indicate that MRI findings, including tumor margin, texture, local invasion or metastases, tumor enhancement, and diffusion restriction, as well as texture parameters can aid the prediction of PNETs grading.

Gd-EOB-DTPA-enhanced magnetic resonance imaging for bile duct intraductal papillary mucinous neoplasms.

AIM: To investigate gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) of intraductal papillary mucinous neoplasms of the bile duct (IPMN-B). METHODS: The imaging findings of five cases of IPMN-B which were pathologically confirmed at our hospital between March 2012 and May 2013 were retrospectively analyzed. Three of these cases were diagnosed by duodenal endoscopy and biopsy pathology, and two cases were diagnosed by surgical pathology. All five patients underwent enhanced and non-enhanced computed tomography (CT), magnetic resonance cholangiopancreatography, and Gd-EOB-DTPA-enhanced MRI; one case underwent both Gd-EOB-DTPA-enhanced MRI and positron emission tomography-CT. The clinical data and imaging results for these cases were compared and are presented. RESULTS: Conventional imaging showed diffuse dilatation of bile ducts and multiple intraductal polypoid and papillary neoplasms or serrated changes along the bile ducts. In two cases, Gd-EOB-DTPA-enhanced MRI revealed dilated biliary ducts and intraductal tumors, as well as filling defects caused by mucin in the dilated bile ducts in the hepatobiliary phase. Gd-EOB-DTPA-enhanced MRI in one case clearly showed a low-signal tumor in the hepatobiliary phase, similar to what was seen by positron emission tomography-CT. In two patients, routine inspection was unable to discern whether the lesions were inflammation or tumors. However, Gd-EOB-DTPA-enhanced MRI revealed a pattern of gradual enhancement during the hepatobiliary phase, and the signal intensity of the lesions was lower than the surrounding liver parenchyma, suggesting tissue inflammation in both cases, which were confirmed by surgical pathology. CONCLUSION: Gd-EOB-DTPA-enhanced MRI reveals the intraductal mucin component of IPMN-B in some cases and the extent of tumor infiltration beyond the bile ducts in invasive cases.

[Evaluation of kidney oxygen bioavailability in acute renal failure by blood oxygen level dependent magnetic resonance imaging].

OBJECTIVE: To assess the kidney oxygen bioavailability in acute renal failure using blood oxygen level dependent (BOLD) magnetic resonance (MR) imaging. METHODS: Twenty-one patients with acute renal failure, including 18 patients with oliguric renal failure, 1 nonoliguric acute renal failure and 2 functional renal failure were enrolled in the study; 20 healthy subjects served as controls. All subjects received renal functional MR examination. BOLD MR imaging with 16 gradient-recalled-echoes on a 1.5-T scanner were performed. R2(*)(1/sec) values of the cortex and medulla and R2(*) ratio of the medulla to cortex (R2(*) ratio of M/C) of the renal were recorded respectively. RESULTS: The R2(*) values of the medulla was higher than those of the cortex in controls (17.64 +/-1.86/sec vs 13.73 +/-0.49/sec, P<0.00). The R2(*) ratio of M/C in controls was 1.28 +/-0.06. The R2(*) values of the medulla (13.31 +/-4.28/sec) and cortex (12.25 +/-2.41/sec) and the R2(* ) ratio of M/C (1.01 +/-0.25) in oliguric renal failure were lower than those in controls (P <0.05). Patients with functional renal failure and nonoliguric acute renal failure had higher R2(*) values in cortex and medulla and higher R2(*) ratio of M/C than those of controls. CONCLUSION: BOLD MRI demonstrates that decreased R2(*) values of cortex and medulla suggest lower oxygen bioavailability in acute renal failure and decreased R2(*)ratio of M/C suggests the disappearance of a steep cortico-medullary gradient of oxygen.

[Value of diffusion-weighted MR imaging in diagnosis of acute rejection after renal transplantation].

OBJECTIVE: To evaluate the feasibility of MR diffusion-weighted imaging (DWI) in diagnosis of acute rejection after renal transplantation. METHODS: Sixty-nine patients who underwent renal transplantation were enrolled in the study. According to the clinical features and renal biopsy, 26 patients were designated in rejection group and 43 in non-rejection group. Patients in non-rejection group underwent MR DWI scan at 2 to 3 weeks after operation, and those in rejection group underwent scan at 5 d before or after renal biopsy. Then the apparent diffusion coefficient (ADC) values of transplanted kidneys were measured with high diffusion sensitivity gradient factors (b values). RESULTS: Patients with acute rejection had significantly lower ADC (P <0.04) than non-rejection patients with all the different b values (b=200, 400, 600, 800, 1,000 s/mm(2)). The ROC curves showed that sensitivity and specificity were best when b value was 800 s/mm(2). CONCLUSION: DWI is a potential and reliable non-invasive method for the diagnosis of the acute rejection after renal transplantation.

Diagnostic value of the fluoroscopic triggering 3D LAVA technique for primary liver cancer.

BACKGROUND: Primary liver cancer (PLC) is one of the common malignant tumors. Liver acquisition with acceleration volume acquisition (LAVA), which allows simultaneous dynamic enhancement of the hepatic parenchyma and vasculature imaging, is of great help in the diagnosis of PLC. This study aimed to evaluate application of the fluoroscopic triggering 3D LAVA technique in the imaging of PLC and liver vasculature. METHODS: The clinical data and imaging findings of 38 adults with PLC (22 men and 16 women; average age 52 years), pathologically confirmed by surgical resection or biopsy, were collected and analyzed. All magnetic resonance images were obtained with a 1.5-T system (General Electrics Medical Systems) with an eight-element body array coil and application of the fluoroscopic triggering 3D LAVA technique. Overall image quality was assessed on a 5-point scale by two experienced radiologists. All the nodules and blood vessel were recorded and compared. The diagnostic accuracy and feasibility of LAVA were evaluated. RESULTS: Thirty-eight patients gave high quality images of 72 nodules in the liver for diagnosis. The accuracy of LAVA was 97.2% (70/72), and the coincidence rate between the extent of tumor judged by dynamic enhancement and pathological examination was 87.5% (63/72). Displayed by the maximum intensity projection reconstruction, nearly all cases gave satisfactory images of branches III and IV of the hepatic artery. Furthermore, small early-stage enhancing hepatic lesions and the parallel portal vein were also well displayed. CONCLUSIONS: Sequence of LAVA provides good multi-phase dynamic enhancement scanning of hepatic lesions. Combined with conventional scanning technology, LAVA effectively and safely displays focal hepatic lesions and the relationship between tumor and normal tissues, especially blood vessels.

[Correlation between pathology and imaging characteristics of hepatic agiomyolipoma].

OBJECTIVE: To discuss CT and MRI characteristics of hepatic angiomyolipoma based on pathological findings. METHODS: The CT and MRI appearances with related pathohistological subtypes of 11 hepatic angiomyolipomas from 10 patients were retrospectively analyzed. RESULT: Ten patients with hepatic angiomyolipomas were subcategorized into lipomatous (3 cases), angiomatous (1 case), myomatous (1 case) and mixed (5 cases) subtypes. Lesions of the lipomatous type were mainly composed of adipocytes which could be easily recognized on both CT and MRI. Abnormal vessels were commonly seen in the angiomatous lesions, which showed pronounced enhancement in the early arterial phase and remained higher than or isodense with the normal parenchyma in the portal phase. The myomatous type was predominantly composed of leiomyoid cells mixed with small amount of adipocytes. The mixed type was the most frequent,evenly comprising sheets of epithelioid muscle cells admixed with islands of adipocytes and abnormal vessels, and showing homogeneously low density on plain CT and low signal intensity on T1-weighted,intermediately high signal intensity on T2-weighted MRI scans. On dynamic study with both CT and MRI, the mixed type exhibited obvious enhancement, which retained to some degree during the portal phase. CONCLUSION: The discrete CT and MRI appearances of hepatic angiomyolipomas with different pathological subtypes depend on the components of the tumor.

[Imaging diagnosis of abdominal solitary fibrous tumor].

OBJECTIVE: To investigate the imaging characteristics of abdominal solitary fibrous tumor (SFT) with its pathological features. METHODS: Six cases of abdominal solitary fibrous tumors were studied using X-ray, CT, MRI examination as well as histopathological and immunohistochemical techniques. RESULT: Contrast enhanced CT showed early intense enhancement as a result of the rich vascularization. On MRI the parenchyma of the tumors showed hypointensity on T1WI, T2WI and some tumors might manifest areas of hyperintensity on T2WI due to myxoid degeneration or hemorrhage. Microscopically, SFT was composed of spindle cells with various patterns and these spindle cells were CD34 positive on immunohistochemistry. CONCLUSION: SFT is a soft tissue tumor originating from mesenchyma. Abdominal SFT shows variable appearance and enhancement pattern on CT and MRI according to tumor cells distribution and myxoid degeneration or hemorrhage within the tumor pathologically.

[Correlation between pathology and image characteristics of retroperitoneal liposarcoma].

OBJECTIVE: To investigate the correlation between the pathological and image features of different subtypes of retroperitoneal liposarcoma. METHODS: Pathological and image characteristics of 21 retroperitoneal liposarcomas were retrospectively analyzed comparing their different histopathological subtypes. RESULTS: This series consisted of 11 well-differentiated, 4 myxoid, 3 round-cell, 2 pleomorphic and 1 dedifferentiated liposarcoma. Well-differentiated liposarcomas were predominantly composed of lipoma-like and sclerosing components. On CT and MRI image, the attenuation and signal intensity of lipoma-like components resembled those of fat, whereas the signal intensity of sclerosing components was similar to those of muscle. Unenhanced CT image of the myxoid subtype showed density resembling that of water. On contrast-enhanced CT image, it showed gradual reticular or sheet-like enhancement. The CT and MRI image appearance of the round cell and pleomorphic subtypes resembled those of nonfatty soft tissue masses with foci of necrosis. The dedifferentiated liposarcoma showed the image feature of a well-differentiated component clearing enhanced soft tissue mass. CONCLUSION: Different subtypes of retroperitoneal liposarcoma show different CT and MRI features relating to their major histologic components. A good understanding of the relation between their radiological and pathological features is helpful to arrive at a correct diagnosis for retroperitoneal liposarcoma.