Liver metastasis from hepatoid adenocarcinoma of the stomach mimicking hepatocellular carcinoma: Dynamic computed tomography findings

AIM: To evaluate the dynamic computed tomography(CT) findings of liver metastasis from hepatoid adenocarcinoma of the stomach(HAS) and compared them with hepatocellular carcinoma(HCC).METHODS: Between January 2000 and January 2015, 8 patients with pathologically proven HAS and liver metastases were enrolled. Basic tumor status was evaluated for the primary tumor location and metastatic sites. The CT findings of the liver metastases were analyzed for tumor number and size, presence of tumor necrosis, hemorrhage, venous tumor thrombosis, and dynamic enhancing pattern.RESULTS: The body and antrum were the most common site for primary HAS(n = 7), and observed metastatic sites included the liver(n = 8), lymph nodes(n = 7), peritoneum(n = 4), and lung(n = 2). Most of the liver metastases exhibited tumor necrosis regardless of tumor size. By contrast, tumor hemorrhage was observed only in liver lesions larger than 5 cm(n = 4). Three patterns of venous tumor thrombosis were identified: direct venous invasion by the primary HAS(n = 1), direct venous invasion by the liver metastases(n = 7), and isolated portal vein tumor thrombosis(n = 2). Dynamic CT revealed arterial hyperattenuation and late phase washout in all the liver metastases.CONCLUSION: On dynamic CT, liver metastasis from HAS shared many imaging similarities with HCC. For liver nodules, the presence of isolated portal vein tumor thrombosis and a tendency for tumor necrosis are imaging clues that suggest the diagnosis of HAS.

Can visceral fat parameters based on computed tomography be used to predict occult peritoneal metastasis in gastric cancer?

BACKGROUND The preoperative prediction of peritoneal metastasis(PM)in gastric cancer would prevent unnecessary surgery and promptly indicate an appropriate treatment plan.AIM To explore the predictive value of visceral fat(VF)parameters obtained from preoperative computed tomography(CT)images for occult PM and to develop an individualized model for predicting occult PM in patients with gastric carcinoma(GC).METHODS A total of 128 confirmed GC cases(84 male and 44 female patients)that underwent CT scans were analyzed and categorized into PM-positive(n=43)and PM-negative(n=85)groups.The clinical characteristics and VF parameters of two regions of interest(ROIs)were collected.Univariate and stratified analyses based on VF volume were performed to screen for predictive characteristics for occult PM.Prediction models with and without VF parameters were established by multivariable logistic regression analysis.RESULTS The mean attenuations of VF_(ROI 1)and VF_(ROI 2)varied significantly between the PM-positive and PMnegative groups(P=0.044 and 0.001,respectively).The areas under the receiver operating characteristic curves(AUCs)of VF_(ROI 1)and VF_(ROI 2)were 0.599 and 0.657,respectively.The mean attenuation of VF_(ROI 2)was included in the final prediction combined model,but not an independent risk factor of PM(P=0.068).No significant difference was observed between the models with and without mean attenuation of VF(AUC:0.749 vs 0.730,P=0.339).CONCLUSION The mean attenuation of VF is a potential auxiliary parameter for predicting occult PM in patients with GC.

Application of computed tomography-based radiomics in differential diagnosis of adenocarcinoma and squamous cell carcinoma at the esophagogastric junction

BACKGROUND The biological behavior of carcinoma of the esophagogastric junction(CEGJ)is different from that of gastric or esophageal cancer.Differentiating squamous cell carcinoma of the esophagogastric junction(SCCEG)from adenocarcinoma of the esophagogastric junction(AEG)can indicate Siewert stage and whether the surgical route for patients with CEGJ is transthoracic or transabdominal,as well as aid in determining the extent of lymph node dissection.With the development of neoadjuvant therapy,preoperative determination of pathological type can help in the selection of neoadjuvant radiotherapy and chemotherapy regimens.AIM To establish and evaluate computed tomography(CT)-based multiscale and multiphase radiomics models to distinguish SCCEG and AEG preoperatively.METHODS We retrospectively analyzed the preoperative contrasted-enhanced CT imaging data of single-center patients with pathologically confirmed SCCEG(n=130)and AEG(n=130).The data were divided into either a training(n=182)or a test group(n=78)at a ratio of 7:3.A total of 1409 radiomics features were separately extracted from two dimensional(2D)or three dimensional(3D)regions of interest in arterial and venous phases.Intra-/inter-observer consistency analysis,correlation analysis,univariate analysis,least absolute shrinkage and selection operator regression,and backward stepwise logical regression were applied for feature selection.Totally,six logistic regression models were established based on 2D and 3D multi-phase features.The receiver operating characteristic curve analysis,the continuous net reclassification improvement(NRI),and the integrated discrimination improvement(IDI)were used for assessing model discrimination performance.Calibration and decision curves were used to assess the calibration and clinical usefulness of the model,respectively.RESULTS The 2D-venous model(5 features,AUC:0.849)performed better than 2D-arterial(5 features,AUC:0.808).The 2D-arterial-venous combined model could further enhance the performance(AUC:0.869).The 3D-venous model(7 features,AUC:0.877)performed better than 3D-arterial(10 features,AUC:0.876).And the 3D-arterial-venous combined model(AUC:0.904)outperformed other single-phase-based models.The venous model showed a positive improvement compared with the arterial model(NRI>0,IDI>0),and the 3D-venous and combined models showed a significant positive improvement compared with the 2D-venous and combined models(P<0.05).Decision curve analysis showed that combined 3D-arterial-venous model and 3D-venous model had a higher net clinical benefit within the same threshold probability range in the test group.CONCLUSION The combined arterial-venous CT radiomics model based on 3D segmentation can improve the performance in differentiating EGJ squamous cell carcinoma from adenocarcinoma.

A correlation of computed tomography perfusion and histopathology in tumor edges of hepatocellular carcinoma

BACKGROUND： The peripheral morphologic characteristics of hepatocellular carcinoma （HCC） reflect tumor growth patterns. Computed tomography （CT） perfusion is a new method to analyze hemodynamic changes in tissues. We assessed the relationship between CT perfusion and histopathologic findings in the periphery of HCC lesions. METHODS： Non-contrast CT, enhanced dual-phase CT, and CT perfusion were performed on 77 subjects （47 patients and 30 controls）. Based on the imaging findings of enhanced dual- phase CT, the tumor edges were classified into three types： type Ⅰ （sharp）; type Ⅱ （blurry）; and type Ⅲ （mixed）. The CT perfusion parameters included hepatic blood flow, hepatic arterial fraction, hepatic arterial perfusion, and hepatic portal perfusion. The tissue sections from resected specimens were subjected to routine hematoxylin and eosin staining and immunohistochemical staining for CD34. The correlations between microvessel density （MVD） and the CT perfusion parameters were analyzed using Pearson＇s product-moment correlation coefficient. Changes in the perfusion parameters in tumor edges of different tumor types were evaluated. RESULTS： Type Ⅰ （sharp）： the pathologic findings showed fibrous connective tissue capsules in the tumor edges, and an MVD 〈30/ram2. Type Ⅱ （blurry）： the histology showed that the edges were clear with no capsules and an MVD 〉30/ram2. Type Ⅲ （mixed）： the pathology was similar to that of types I and II, and an MVD 〉30/mm~. Hepatic blood flow, hepatic arterial fraction, hepatic arterial perfusion, and hepatic portal perfusion were significantly increased in the tumor edges of HCC patients compared to those of the controls （P〈0.05）. The correlation between CT perfusion parameters and MVD was higher in blurry tumor edges of type II than in those of types Ⅰ or Ⅲ. CONCLUSION： CT perfusion imaging of tumor edges may be helpful in revealing histopathological features, and indirectly reflect angiogenic changes of HCCs.

Application and progress of medical imaging in total mesopancreas excision for pancreatic head carcinoma

Pancreatic head carcinoma(PHC)is one of the common gastrointestinal malignancies with a high morbidity and poor prognosis.At present,radical surgery is still the curative treatment for PHC.However,in clinical practice,the actual R0 resection rate,the local recurrence rate,and the prognosis of PHC are unsatisfactory.Therefore,the concept of total mesopancreas excision(TMpE)is proposed to achieve R0 resection.Although there have various controversies and discussions on the definition,the range of excision,and clinical prognosis of TMpE,the concept of TMpE can effectively increase the R0 resection rate,reduce the local recurrence rate,and improve the prognosis of PHC.Imaging is of importance in preoperative examination for PHC;however,traditional imaging assessment of PHC does not focus on mesopancreas.This review discusses the application of medical imaging in TMpE for PHC,to provide more accurate preoperative evaluation,range of excision,and more valuable postoperative follow-up evaluation for TMpE through imaging.It is believed that with further extensive research and exploratory application of TMpE for PHC,large-sample and multicenter studies will be realized,thus providing reliable evidence for imaging evaluation.

CT动态容积灌注成像检出早期胃癌并评估其病理分型

目的 观察CT动态容积灌注(DVPCT)成像检出早期胃癌并鉴别其病理分型的价值。方法 回顾性分析127例经病理证实的早期胃癌患者,根据术前检查方式分为增强CT组(n=67)或DVPCT组(n=60);比较组间一般资料、CT资料,以及DVPCT组内胃印戒细胞癌(SRCC)与胃腺癌的强化程度、门静脉期与延迟期峰值期相及峰值时间;绘制受试者工作特征(ROC)曲线,计算曲线下面积,评估DVPCT时间-密度曲线(TDC)鉴别早期SRCC与腺癌的效能。结果 DVPCT组肿瘤检出率、剂量长度乘积及有效剂量均高于增强CT组(P均<0.05);2组患者年龄、性别、病理分型、肿瘤位置及肿瘤最大径差异均无统计学意义(P均>0.05)。52例(52/60,86.67%)经DVPCT检出早期胃癌的患者中,SRCC 12例、腺癌39例、黏液腺癌1例;其中,早期胃SRCC与早期胃腺癌患者肿瘤强化程度、门静脉期及延迟期峰值期相及峰值时间差异均有统计学意义(P均<0.05)。以峰值时间37.3 s为最佳截断值,DVPCT TDC鉴别早期胃SRCC与早期胃腺癌的敏感度、特异度、阳性预测值、阴性预测值、准确率及曲线下面积分别为83.33%、84.62%、62.50%、94.29%、84.31%及0.895。结论 DVPCT检出早期胃癌效果优于常规增强CT;TDC可有效鉴别早期胃SRCC与早期胃腺癌。

Eight-year follow-up of locally advanced lymphoepithelioma-like carcinoma at upper urinary tract: A case report

BACKGROUND Urinary tract lymphoepithelioma-like carcinoma is rarely seen.Although it is termed after lymphoepithelioma at the nasopharynx,it behaves more like high grade urothelial carcinoma by immunohistochemical features.Most published literatures focused on its rarity but few discussed results of long-term follow-ups.As no available guidelines are applicable,we postulated that principles should be similar to that of urothelial carcinoma at urinary tract.As of now,this work features the longest follow-up of this cancer at the upper urinary tract.CASE SUMMARY A 63-year-old female had a chief complaint of intermittent left flank pain for 2 mo,along with accompanying symptoms including vomiting and body weight loss,about 7 kg over 2 mo.Laboratory data showed normocytic anemia,mildly poor renal function,and hyperparathyroidism.Urine analysis showed mild hematuria.Computed tomography showed a 4.2-cm-width irregular mass over left renal pelvic and enlarged lymph node at the left renal hilum.Whole-body bone scan was negative of active bone lesions.Biopsy from ureteroscopy showed urothelial carcinoma.Specimen from laparoscopic nephroureterectomy with bladder cuff resection showed lymphoepithelioma-like carcinoma with muscular invasion(pT3).She took adjuvant chemotherapies of 2 cycles and full courses of radiation therapy.No recurrence was observed with designed investigative programs.CONCLUSION Locally advanced urinary tract lymphoepithelioma-like carcinoma could benefit from nephroureterectomy and bladder cuff excision in terms of recurrence-free survival.

Development and validation of a CT-based radiomics nomogram for preoperative prediction of tumor histologic grade in gastric adenocarcinoma

Objectives:To develop and validate a radiomics nomogram for preoperative prediction of tumor histologic grade in gastric adenocarcinoma(GA).Methods:This retrospective study enrolled 592 patients with clinicopathologically confirmed GA(low-grade:n=154;high-grade:n=438)from January 2008 to March 2018 who were divided into training(n=450)and validation(n=142)sets according to the time of computed tomography(CT)examination.Radiomic features were extracted from the portal venous phase CT images.The Mann-Whitney U test and the least absolute shrinkage and selection operator(LASSO)regression model were used for feature selection,data dimension reduction and radiomics signature construction.Multivariable logistic regression analysis was applied to develop the prediction model.The radiomics signature and independent clinicopathologic risk factors were incorporated and presented as a radiomics nomogram.The performance of the nomogram was assessed with respect to its calibration and discrimination.Results:A radiomics signature containing 12 selected features was significantly associated with the histologic grade of GA(P<0.001 for both training and validation sets).A nomogram including the radiomics signature and tumor location as predictors was developed.The model showed both good calibration and good discrimination,in which C-index in the training set,0.752[95%confidence interval(95%CI):0.701-0.803];C-index in the validation set,0.793(95%CI:0.711-0.874).Conclusions:This study developed a radiomics nomogram that incorporates tumor location and radiomics signatures,which can be useful in facilitating preoperative individualized prediction of histologic grade of GA.

Multiphase hepatic scans with multirow- detector helical CT in detection of hypervascular hepatocellular carcinoma

BACKGROUND: Multirow-detector helical CT (MDCT) allows faster Z-axis coverage and improves longitudinal re- solution to scan the entire liver. This study was to evaluate the value of multiphase hepatic CT scans using MDCT in diagnosing hypervascular hepatocellular carcinoma (HCC). METHODS: Multiphase hepatic CT scans in 40 patients were carried out with a Marconi Mx8000 MDCT scanner. The scans of early arterial phase (EAP), late arterial phase (LAP) and portal venous phase (PVP) were started at 21, 34 and 85 seconds after injection of contrast medium, re- spectively. The number of detected lesions was calculated in each phase. The density of the liver and tumor was great- er than 1 cm for HCC, and the density of the liver and tumor in each phase was statistically calculated. RESULTS: A total of 61 lesions were found in the 40 pa- tients , and lesions greater than 1 cm were seen in 47 cases. The density differences between the liver and tumor were statistically significant (P<0.05) at the LAP and EAP and between the LAP, EAP and PVP. In the 61 lesions, the de- tectability in the EAP, LAP and the double arterial phases (DAP) was 32%, 87%, and 94%, respectively. Significant difference was found between the LAP plus PVP and the EAP plus PVP; but no significant difference was observed between the DAP plus PVP and the LAP plus PVP. CONCLUSIONS: The utility of MDCT scan in the liver has optimized the protocol of arterial phase scan. MDCT is possible to scan the entire liver in a real arterial phase and it is very valuable in the detection of small HCC.

Correlation between Calcified Liver Metastases and Histopathology of Primary Colorectal Carcinoma in Chinese

The study examined the association between calcified liver metastases and the histopathology of the primary colorectal carcinoma in Chinese.The clinical,pathological and CT data were retrospectively analyzed in 210 patients (mean age:54.2 years) with liver metastases from colorectal carcinoma.Plain CT scanning and contrast-enhanced scanning were performed in all the patients.For the contrast-enhanced examination,iohexol was injected by using a high pressure syringe at a flow rate of 2.5-3.0 mL/s.The arterial phase lasted approximately 25 s and the portal venous phase about 60 s.All patients had no history of chronic liver diseases and had never received interventional treatments.χ 2-test was used to analyze the rate of calcification in the liver metastasis from colorectal cancer of different differentiation degrees.Among the 210 cases of liver metastases,22 patients (10.5%) were found to have calcified liver metastases on CT scan.Two patients with calcified liver metastasis received lumpectomy and developed calcification in recurrent tumors.Another two patients had calcification in newly developed tumor masses.And the calcification in the newly developed masses was similar to that of their primary counterparts in terms of morphology and distribution.On the enhanced CT scan,the tumors exhibited no enhancement during hepatic arterial phase and showed slight rim enhancement during portal venous scan in the 22 cases.The calcification became obscure on contrast-enhanced scans.Histopathologically,the primary tumors were well-differentiated adenocarcinoma in 6 cases,moderately-differentiated adenocarcinoma in 10,poorly-differentiated adenocarcinoma in 4 and mucinous adenocarcinoma in 2 among the 22 cases.No statistical correlation was noted between the incidence of calcified liver metastasis and the pathological subtypes and differentiation degrees of the primary colorectal carcinoma.It was concluded that calcified liver metastases may result from colorectal adenocarcinomata of different differentiation degrees or mucinous adenocarcinomata in Chinese population.There is no correlation between calcification of liver metastases and the pathological subtype of the primary colorectal carcinoma in Chinese,which is different from the findings that calcified metastases were associated with colorectal mucinous adenocarcinoma in other ethnic groups.

胃癌CT表现及其对手术切除可行性的探讨

目的：探讨胃癌CT表现、诊断价值及CT扫描对胃癌手术切除可行性评估。材料与方法；60例常规CT扫描的胃癌病例，并行手术病理对照，评价手术切除可行性。结果：除3例原胃癌，5例早期胃癌外均有明显胃癌CT征象，胃壁增厚42例，软组织肿块24例，胃周脂肪线改变35例，胃周及远处淋巴结肿大13例，邻近器官及远处器官转移5例，胃壁明显强化28例。结论：胃癌CT扫描能显示内脏及胃壁病变、胃周及邻近器官浸润，远处脏器及淋巴结转移等特征，是胃癌定性诊断、术前分期及术后随访的有效手段，是术前评估的重要方法。

中晚期胃癌的X线、CT和B超表现(附186例分析)

目的 :探讨胃癌的X线、CT和B超特征性表现及意义。方法 :186例胃癌均行气钡双重造影 ,其中 63例行CT扫描 ,3 7例行B超检查 ,所有病例均经手术病理证实 ,分析全部病例的影像学表现。结果 :1.X线气钡双重造影检出胃癌 :蕈伞型 65例 ,溃疡型 82例 ,浸润型 3 9例。 2 .CT检出胃癌 :胃壁增厚 3 7例 ,胃内肿块 2 6例 ,胃周脂肪线消失 3 2例 ,胃周及远处淋巴结肿大 2 7例。 3 .B超检出胃癌 :胃壁增厚 17例 ,胃内肿块 11例 ,2 5例显示第 3、4、5层回声线消失、不清或中断 ,13例显示胃周脏器侵润及远处脏器转移 ,12例显示淋巴结转移。结论 :X线气钡双重造影是诊断胃癌的首选检查方法 。

CT鉴别诊断胃神经内分泌癌与胃腺癌

目的观察CT鉴别诊断胃神经内分泌癌(GNEC)与胃腺癌(GC)的效能。方法回顾性分析经病理确诊的62例GNEC(GNEC组)和70例GC(GC组)患者,手术或活检前7天内均接受腹部增强CT检查,对比组间临床资料及CT特征。针对差异有统计学意义的CT特征进行Logistic回归分析,并绘制受试者工作特征(ROC)曲线,分析CT特征对鉴别GNEC与GC的效能。结果组间肿瘤边界、囊变/坏死和肝转移以及肿瘤厚径、静脉-动脉期强化率差异均有统计学意义(P均<0.05)。肿瘤边界、厚径、囊变/坏死、肝转移及强化特点可作为独立预测因素鉴别GNEC与GC(P均<0.05)。ROC曲线结果显示,以上述参数单独鉴别GNEC与GC的曲线下面积(AUC)分别为0.63、0.69、0.65、0.62、0.63,各参数联合鉴别诊断的AUC可达0.83。结论CT特征可用于鉴别GNEC与GC。

胃神经内分泌癌CT与临床病理表现

胃神经内分泌癌(gastric neuroendocrine carcinoma,GNEC)是原发于胃神经内分泌细胞的高度恶性肿瘤,2010年WHO消化系统肿瘤分类[1]和2011年中国胃肠胰神经内分泌肿瘤病理学诊断共识[2]将神经内分泌肿瘤分为神经内分泌瘤(G1、G2级)、神经内分泌癌(neuroendocrine carcinoma,NEC;G3级)及混合性腺神经内分泌癌。既往普遍认为NEC临床少见。

进展期胃癌的CT诊断及手术可切除性评估

目的 :探讨进展期胃癌的CT检查方法及表现 ,并对胃癌手术可切除性的术前评估进行研究 ,以避免不必要的剖腹手术。方法 :分析 5 0例经胃镜活检和 /或手术病理证实的进展期胃癌的CT表现 ,并根据肿瘤的生长情况进行手术可切除性的前瞻性评估。结果 :胃底贲门癌 1 3例 ,胃体癌 2 2例 ,胃窦癌 9例 ,病变占据两个分区以上者 6例。 5 0例胃癌均显示胃壁有不同程度的增厚 ,部分胃壁有软组织肿块形成 ,粘膜面有溃疡形成 ,胃腔及贲门狭窄 ,贲门管壁增厚 ,食道下段受累以及周围组织器官侵犯等。结论 :CT对进展期胃癌的定位定性诊断与胃镜活检和 /或手术病理符合率较高 ,肿瘤检出率可达 1 0 0 %。CT对术前肿瘤的可切除性评估有较高的参考价值 ,手术前判断为可切除组的病例手术切除率达 94 .3%。胃癌术前CT诊断具有重要临床意义 。

Imaging findings of primary gastric plasmacytoma:A case report

Primary gastric plasmacytoma(GP)is a rare extramedullary plasmacytoma with clinical and imaging features that are common among other gastric tumors,such as gastric adenocarcinomas,gastric stromal tumors,and lymphomas.Here,we present a histologically confirmed case of primary GP examined with biphasic computed tomography(CT),magnetic resonance imaging(MRI),and endosonography.A well-circumscribed extraluminal mass appearing as homogeneous attenuation/intensity with gradual enhancement was identified on biphasic enhancement CT and MRI.This mass was hyperintense on diffusion-weighted imaging and hypointense on the apparent diffusion coefficient map,implying that water diffusion in the mass was restricted.In addition,endosonography indicated a low echogenic mass in the gastric wall.These imaging findings increase the available knowledge about imaging of this disease and provide valuable information for differentiating primary GP from common gastric tumors.

肾透明细胞癌合并腹腔Castleman病、胃平滑肌瘤1例

患者男,47岁,糖尿病病史4年余,无高血压、心脏病等病史。体检CT平扫发现左肾占位。1天后复查,增强CT：左肾见一软组织占位（图1A）,内见小片状坏死区,边界清晰,增强呈＂快进快退＂。左下腹见一类圆形软组织肿块（图1B）,密度均匀,边界清晰,边缘见点状钙化灶,增强呈均匀明显强化,周围见多发小淋巴结,中心见裂隙样低密度影。

^(18)F-FDG PET/CT对不同印戒细胞成分胃癌的诊断价值

目的探讨^(18)F-FDG PET/CT对不同印戒细胞成分胃癌的诊断价值。资料与方法回顾性分析67例行^(18)F-FDG PET/CT检查的胃腺癌患者的临床资料,均经胃镜或手术病理结果确诊,并根据印戒细胞成分分为胃印戒细胞癌(SRC)组、部分印戒细胞癌(Mixed-SRC)组及非印戒细胞腺癌(Non-SRC)组。分别测量各组胃癌原发灶最大标准化摄取值(SUVmax)、邻近正常胃组织SUVmax,计算两者标准化比值(SUR)。设定SUR>1为阳性阈值,分别评估^(18)F-FDG PET/CT对3组患者的诊断效能。结果^(18)FFDG PET/CT对3组患者原发灶的检测敏感度分别为71.4%、92.3%和97.5%。3组患者原发灶SUVmax、SUR差异均有统计学意义(P<0.05)。其中,SRC组与Mixed-SRC组、Non-SRC组间差异均有统计学意义(P<0.05);Mixed-SRC组与Non-SRC组间差异无统计学意义(P>0.05)。本组胃腺癌原发灶SUVmax、SUR与CT测量病灶厚度均呈正相关(r=0.764、0.620,P<0.001)。结论^(18)F-FDG PET/CT对Mixed-SRC及Non-SRC的诊断及分期方面具有良好的应用价值,但对SRC的诊断及分期存在局限性。

Differentiation of Renal Oncocytoma and Renal Clear Cell Carcinoma Using Relative CT Enhancement Ratio

Background：The difference between renal oncocytomas （RO） and renal clear cell carcinomas （RCCs） presents the greatest diagnostic challenge.The aim of this study was to retrospectively determine ifRO and RCCs could be differentiated on computed tomography （CT） images on the basis of their enhancement patterns with a new enhancement correcting method.Methods：Forty-six patients with a solitary renal mass who underwent total or partial nephrectomy were included in this study.Fourteen of those were RO and 32 were RCCs.All patients were examined with contrast-enhanced CT.The pattern and degree of enhancement were evaluated.We selected the area that demonstrated the greatest degree of enhancement of the renal lesion in the corticomedullary nephrographic and excretory phase images.Regions of interest （ROI） were also placed in adjacent normal renal cortex for normalization.We used the values of the normal renal cortex that were measured at the same time as divisors.The ratios of lesion-to-renal cortex enhancement were calculated for all three phases.The Student＆#39;s t-test and Pearson＆#39;s Chi-square test were used for statistical analyses.Results：All RCCs masses showed contrast that appeared to be better enhanced than RO on all contrast-enhanced phases of CT imaging,but there was no significant difference in absolute attenuation values between these two diseases （P 〉 0.05）.The ratio of lesion-to-cortex attenuation in the corticomedullary phase showed significantly different values between RO and RCCs.The degree of contrast enhancement in RCCs was equal to or greater than that of the normal renal cortex,but it was less than that of the normal cortex in RO in the corticomedullary phase.The ratio of lesion-to-cortex attenuation in the corticomedullary phase was higher than the cut off value of 1.0 in most RCCs （84%,27/32） and lower than 1.0 in most RO （93%,13/14） （P 〈 0.05）.In the nephrographic phase,the ratio of lesion-to-cortex attenuation was higher than that in the corticomedullary phase in most RO （71%,10/14）,showing a prolonged enhancement pattern; and was lower than that in most RCCs （97%,31/32）,showing an early washout pattern （P 〈 0.05）.In the differentiation of RO from RCCs,the sensitivity was 93%,specificity 84%,positive predictive value 72%,negative predictive value 84%,and accuracy for RO was 87,if the ratio of lesion-to-cortex attenuation in a cortex phase was lower than the cutoff value of 1.0.The sensitivity was 71%,specificity was 97%,positive predictive value was 91%,negative predictive value was 91%,and accuracy for RO was 89%,if the ratio of lesion-to-cortex attenuation in nephrographic phase was higher than that in the corticomedullary phase.Conclusions：The ratios of renal lesion-to-cortex attenuation ratios may be helpful in differentiating RO from RCCs.

Small hepatocellular carcinoma with peripheral enhancement:pathological correlation with dual phase images by helical CT

Background The peripheral enhancement of small hepatocellular carcinoma （SHCC） is a rare appearance in dual phase images by helical computed tomography （CT）. This study discusses this phenomenon and its correlative histopathology. Methods The helical CT dual phase appearance of peripheral enhancement in SHCC was analyzed in 21 cases （22 lesions）. All lesions were confirmed as SHCC by histopathological examination. Results In these 22 lesions, enhanced peripheral ring in 20 lesions was incomplete, the thickness of enhanced peripheral ring varied and mural node could be found in hepatic arterial phase; only 2 lesions had complete peripheral ring enhancement and ring of uniform thickness in hepatic arterial phase. The enhancement of some peripheral rings and mural nodes dropped to very low density in portal venous phase. The tumour cells were grade I in 3 lesions, II in 16, III in 2 and IV in 1. The vascular supply was more abundant at the border than in the centre of 15 lesions and the vascular supply was deficient in both centre and border of the remaining 7 lesions. In 3 lesions, the pseudocapsule showed in the border of the lesion. In 12 lesions, flecks of necrosis were found in the border and/or centre of the lesion. Conclusions The characteristic peripheral enhancement in helical CT dual phase images of small hepatocellular carcinoma correlates with different vascular supplies, fibrous capsule and necrosis of the lesion.