Detection of small hepatocellular carcinoma： Comparison of dynamic enhancement magnetic resonance imaging and multiphase multirow-detector helical CT scanning

AIM: To compare the gadolinium-enhanced multiphase dynamic magnetic resonance imaging (MRI) and multiphase multirow-detector helical CT (MDCT) scanning for detection of small hepatocellular carcinoma (HCC). METHODS: MDCT scanning and baseline MRI with SE T1-WI and T2-WI sequence combined with FMPSPGR sequence were performed in 37 patients with 43 small HCCs. Receiver operating characteristic (ROC) curves were plotted to analyze the results for modality. RESULTS: The areas below ROC curve (Az) were calculated. There was no statistical difference in dynamic enhancement MDCT and MRI. The detection rate of small HCC was 97.5%-97.6% on multiphase MDCT scanning and 90.7%-94.7% on MRI, respectively. The sensitivity of detection for small HCC on MDCT scanning was higher than that on dynamic enhancement MRI. The sensitivity of detection for minute HCC (tumor diameter ≤ 1 cm) was 90.0%-95.0% on MDCT scanning and 70.0%-85.0% on MRI, respectively. CONCLUSION: MDCT scanning should be performed for early detection and effective treatment of small HCC in patients with chronic hepatitis and cirrhosis during follow-up.     

Contrast-enhanced ultrasonographic findings of hepatic paragonimiasis

AIM: To investigate the features of hepatic paragonimiasis on contrast-enhanced ultrasound (CEUS) imag- ing. METHODS: Fifteen patients with hepatic paragonimiasis who were admitted to our hospital between March 2008 and August 2012 were enrolled to this study. The conventional ultrasound and CEUS examinations were performed with a Philips IU22 scanner with a 1-5-MHz convex transducer. After conventional ultrasound scanning was completed, the CEUS study was performed. Pulse inversion harmonic imaging was used for CEUS. A bolus injection of 2.4 mL of a sulfur hexafluoride-filled microbubble contrast agent (SonoVue) was administered. CEUS features were retrospectively reviewed and correlated with pathological findings. RESULTS: In total, 16 lesions were detected on CEUS. The mean size of the lesions was 4.4 ± 1.6 cm (range, 1.7-6.6 cm). Subcapsular location was found in 12 lesions (75%). All the lesions were hypoechoic. Six lesions (37.5%) were of mixed content, seven (43.8%) were solid with small cystic areas, and the other three (18.8%) were completely solid. Ten lesions (62.5%) were rim enhanced with irregular tract-like nonenhanced internal areas. Transient wedge-shaped hyperenhancement of the surrounding liver parenchyma was seen in seven lesions (43.8%). Areas with hyperor iso-enhancement in the arterial phase showed contrast wash-out and appeared hypoenhanced in the late phase. The main pathological findings included: (1) coagulative or liquefactive necrosis within the lesion, infiltration of a large number of eosinophils with the formation of chronic eosinophilic abscesses and sporadic distribution of Charcot-Leyden crystals; and (2) hyperplasia of granulomatous and fibrous tissue around the lesion. CONCLUSION: Subcapsular location, hypoechogenicity, rim enhancement and tract-like nonenhanced areas could be seen as the main CEUS features of hepatic paragonimiasis.     

Mangafodipir trisodium-enhanced magnetic resonance imaging for evaluation of pancreatic mass and mass-like lesions

AIM: To investigate the role of mangafodipir trisodium (MnDPDP) in focal pancreatic masses and mass-like lesions by evaluating contrast uptake features of the lesions and pancreatic parenchyma after contrast medium injection. METHODS: A total of 37 patients with pancreatic mass or mass-like lesions were examined by unenhanced and MnDPDP-enhanced magnetic resonance imaging (MRI). RESULTS: MRI was obtained 20-40 min after infusion of MnDPDP and homogeneous contrast enhancement was observed in normal pancreas parenchyma. In patients with atrophic pancreas there was no enhancement in pancreatic parenchyma on MnDPDP-enhanced MRI. In 37 patients with 41 pancreatic masses and mass-like lesions, contrast enhancement was observed at 5 lesions on MnDPDP enhanced MRI. Three of these 5 lesions were focal pancreatitis and the other 2 were adenocarcinoma. No contrast enhancement was determined in 36 pancreatic masses and mass-like lesions in 32 patients. CONCLUSION: MnDPDP contrast-enhanced MRI, especially in cases with no parenchyma atrophy, can distinguish focal pancreatic lesion margins. Information about the function of pancreatic parenchyma can be obtained out of tumor. MnDPDP facilitates staging of pancreatic tumors by detection of metastatic lesions in the liver. In addition, diminished heteregenous uptake of MnDPDP in patients with pancreatitis may be helpful in differential diagnosis.     

Rectal gastrointestinal stromal tumors:Imaging features with clinical and pathological correlation

AIM:To investigate computed tomography(CT) and magnetic resonance imaging(MRI) manifestations of rectal gastrointestinal stromal tumors(GISTs) in order to enhance the recognition of these rare tumors.METHODS:Fourteen patients with pathologically proven rectal GISTs were retrospectively reviewed.Patient histories were retrospectively reviewed for patient age,gender,presenting symptoms,endoscopic investigations,operation notes and pathologic slides.All tumors were evaluated for CD117,CD34 expression,and the tumors were stratified according to current criteria of the National Institutes of Health(NIH).In all cases the first pre-operation imaging findings(CT and MRI,n = 3;MRI only,n = 8;CT only,n = 3) were analyzed by two experienced radiologists by consensus,which include:tumor size,shape,CT density(hypodense,isodense and hyperdense),MRI signal intensity(hypointense,isointense and hyperintense),epicenter(intraluminal or extraluminal),margin(well-defined or ill-defined),internal component(presence of calcifications,necrosis,hemorrhage or ulceration),pattern and degree of enhancement,invasion into adjacent structures.After review of the radiologic studies,clinical and pathological findings were correlated with radiological findings.RESULTS:The patients,13 men and 1 woman,were aged 31-62 years(mean = 51.5 ± 10.7 years).The most common initial presentation was hematochezia(n = 6).The mean tumor diameter was 5.68 ± 2.64 cm(range 1.5-11.2 cm).Eight lesions were round or oval,and 6 lesions were irregular.Eleven lesions were welldefined and 3 had ill-defined margins.Ten tumors were extraluminal and 4 were intraluminal.The density and MR signal intensity of the solid component of the lesions were similar to that of muscle on unenhanced CT(n = 6) and T1-weighted images(n = 11),and hyperintense on T2-weighted MR images.Calcification was detected in 2 tumors.Following intravenous injection of contrast media,3 lesions had mild enhancement and 11 lesions had moderate enhancement.Enhancement was homogenous in 3 lesions and hete     

Single-level dynamic spiral CT of hepatocellular carcinoma:Correlation between imaging features and density of tumor microvessels

AIM:To investigate the correlation of enhancement featuresof hepatocellular carcinoma (HCC) revealed by single-leveldynamic spiral CT scanning (DSCT) with tumor microvesseldensity (MVD),and to determine the validity of DSCT inassessing in vivo tumor angiogenic activity of HCC.METHODS:Twenty six HCC patients were diagnosedhistopathologically.DSCT was performed for all patientsaccording to standard scanning protocol.Time-density curveswere generated,relevant curve parameters were measured,and gross enhancement morphology was analyzed.Operationwas performed to remove HCC lesions 1 to 2 weeks followingCT scan.Histopathological slides were carefully prepared forthe standard F_8RA immunohistochemical staining and tumormicrovessel counting.Enhancement imaging features of HCClesions were correlatively studied with tumor MVD and itsintra-tumor distribution characteristics.RESULTS:On DSCT images of HCC lesions,three patternsof time-density curve and three types of gross enhancementmorphology were recognized.Histomorphologically,thedistribution of positively stained tumor endothelial cells withintumor was categorized into 3 types.Curve parameters suchas peak enhancement value and contrast enhancement ratiowere significantly correlated with tumor tissue MVD (r=0.508and r=0.423,P<0.01 and P<0.05 respectively).Both thepattern of time-density curve and the gross enhancementmorphology of HCC lesions were also correlated with tumorMVD,and reflected the distributive features of tumormicrovessels within HCC lesions.Correlation between thelikelihood of intrahepatic metastasis of HCC lesions withdensely enhanced pseudocapsules and rich pseudocapsulartumor MVD was found.CONCLUSION:Enhancement imaging features of HCClesions on DSCT scanning are correlated with tumor MVD,and reflect the intra-tumor distribution characteristics of tumor microvessels.DSCT is valuable in assessing theangiogenic activity and tumor neovascularity of HCC patientsin vivo.     

Epithelioid angiomyolipoma of the liver： Cross-sectional imaging findings of 10 immunohistochemically-verified cases

AIM： To retrospectively evaluate the computed tomography （CT）/magnetic resonance imaging （MRI） imaging features of epithelioid angiomyolipoma of the liver （Epi-HAML）, with pathology as a reference. METHODS： The CT/MRI findings （number, diameter, lobar location, and appearance of lesions） in a series of 10 patients with 12 pathologically proven epithelioid angiomyolipomas of the liver were retrospectively analyzed. The imaging features, including attenuation/ signal intensity characteristics, presence of fat, hypervascular, outer rim, and vessels within lesion, were evaluated and compared with that of non-Epi- HAML in 11 patients （13 lesions）. The Fisher exact test was used to compare difference in probability of imaging features between the two types. RESULTS： For 21 patients, CT images of 15 patients and MR images of six patients were available. No patient underwent two examinations. For the 15 patients with a CT scan, all HAML lesions in the two groups （10 Epi-HAML and seven non-Epi-HAML） manifested as hypoattenuation. For the six patients with MRI, all lesions （two Epi-HAML and six non-Epi- HAML） were hypointense on TlWI （fat suppression） and hyperintense on T2WI. There were 10 non-Epi-HAML, but only two Epi-HAML lesions showed the presence of fat, which significantly different between the two types （P = 0.005）. On the dynamic contrast enhancement （DCE） imaging, eight Epi-HAML, and 13 non-Epi lesions manifested as hypervascular. Punctate or curved vessels were displayed in 10 Epi-HAML as well as in nine non- Epi lesions and outer rim enhancement could be found with eight Epi-HAML as well as six non-Epi lesions. CONCLUSION： Little or no presence of adipose tissue was found to be an imaging feature of Epi- HAML, compared with the non-Epi type. In addition, hypervascularity with opacification of central punctiform or filiform vessels on DCE would be a characteristic enhancement pattern for Epi-HAML.     

Solitary fibrous tumors in abdomen and pelvis:Imaging characteristics and radiologic-pathologic correlation

AIM:To describe the imaging features of solitary fibrous tumors(SFTs)in the abdomen and pelvis,and the clinical and pathologic correlations.METHODS:Fifteen patients with pathologically confirmed SFTs in the abdomen and pelvis were retrospectively studied with imaging techniques by two radiologists in consensus.Patients underwent unenhanced and contrast-enhanced imaging,as follows:3 with computed tomography(CT)and magnetic resonance imaging(MRI)examination,8 with CT examination only,and 4 with MRI examination only.Image characteristics such as size,shape,margin,attenuation or intensity,and pattern of enhancement were analyzed and correlated with the microscopic findings identified from surgical specimens.In addition,patient demographics,presentation,and outcomes were recorded.RESULTS:Of the 15 patients evaluated,local symptoms related to the mass were found in 11 cases at admission.The size of the mass ranged from 3.4 to 25.1cm(mean,11.5 cm).Nine cases were round or oval,6were lobulated,and 10 displaced adjacent organs.Unenhanced CT revealed a heterogeneous isodense mass in 7 cases,homogeneous isodense mass in 3 cases,and punctuated calcification in one case.On MRI,most of the lesions(6/7)were heterogeneous isointense and heterogeneous hyperintense on T1-weighted images and T2-weighted images,respectively.All tumors showed moderate to marked enhancement.Heterogeneous enhancement was revealed in 11 lesions,and 7of these had cysts,necrosis,or hemorrhage.Early nonuniform enhancement with a radial area that proved to be a fibrous component was observed in 4 lesions,which showed progressive enhancement in the venous and delayed phase.No statistical difference in the imaging findings was observed between the histologically benign and malignant lesions.Three patients had local recurrence or metastasis at follow-up.CONCLUSION:Abdominal and pelvic SFTs commonly appeared as large,solid,well-defined,hypervascular masses with variable degrees of necrosis or cystic change that often displaced adjacent structures.     

Characteristics of liver on magnetic resonance diffusion-weighted imaging： Dynamic and image pathological investigation in rabbit liver VX-2 tumor model

AIM： To investigate dynamical and image pathological characteristics of the liver on magnetic resonance （MR） diffusion-weighted imaging （DWI） in the rabbit VX-2 tumor model.
METHODS： Forty New Zealand rabbits were included in the study and VX-2 tumor piece was implanted intrahepatically. Fifteen animals received two intrahepatic implantations while 25 had one intrahepatical implantation. DWI, T1- and T2-weighted of magnetic resonance imaging （MRI） were carried out on the 7th and the 14th d after implantation and DWI was conducted, respectively on the 21th d. Ten VX-2 tumor samples were studied pathologically.
RESULTS： The rate of lump detected by DWI, TlWI and T2WI was 78.7%, 10.7% and 53.5% （X^2 =32.61, P 〈 0.001） on the 7th d after implantation and 95.8%, 54.3% and 82.9% （X^2 = 21.50, P 〈 0.001） on the 14th d. The signal of most VX-2 tumors on DWI was uniform and it was equal diffusion coefficient （ADC）. did not decrease on the 7th on the map of apparent The signal of VX tumors d after implantation, most of them slowly growing during the week following implantation without significant cell dying within the tumor. VX-2 tumors grew increasingly within 14 d after implantation but the signal of most VX-2 tumors on DWI or on the map of ADC was uniform or uneven and ADC of VX tumors decreased obscurely or slightly because tumor necrosis was still not obvious. On the 21th d after implantation, the signal of most VX-2 tumors on DWI or on the map of ADC was uneven because tumor necrosis was evident and ADC of VX-2 tumor necrotic areas decreased. The areas of viable cells in VX-2 tumors manifested a high signal on DWI and a low signal on the map of ADC. The areas of dead cells or necrosis in VX-2 tumors manifested low signals on DWI and low, equal or high signals on the map of ADC but they manifested high signals on DWI and on the map of ADC at the same time when the areas of necrotic tumor became liquefied or cystic. The border of tumors on DWI appeared gradually distinct and intern     

Ferucarbotran versus Gd-DTPA-enhanced MR imaging in the detection of focal hepatic lesions

AIM: To evaluate the efficacy of ferucarbotran-enhanced MR imaging in the detection of focal hepatic lesions compared to plain and Gd-DTPA-enhanced MR imaging. METHODS: Fifty-nine patients with suspected focal hepatic lesions were admitted to the study. Plain MR imaging (FSE T2WI with fat suppression and GRE T1WI sequences) and Gd-DTPA dynamic enhanced MR of the liver were initially performed followed by ferucarbotran- enhanced MR imaging 48 h later (including GRE T1WI, FSE T2WI with fat suppression, and GRE T2*WI sequences). Images were reviewed independently by three observers. Results were correlated with surgery and pathologic examination or reference examination, and sensitivity was statistically calculated for the different MR imaging sequences. RESULTS: Among all confirmed lesions (n = 133), ferucarbotran-enhanced MR imaging revealed 130 lesions on FSE T2WI with fat suppression, 115 lesions on dynamic T1WI GRE, and 127 lesions on GRE T2*WI. Pre-contrast MR imaging revealed only 84 lesions on GRE T1WI and 106 lesions on FSE T2WI with fat suppression, while Gd-DTPA dynamic enhanced GRE T1WI revealed 123 lesions. For 44 micro-lesions (< 1.0 cm) in all patients the detection rates were as follows: ferucarbotran-enhanced FSE T2WI with fat suppression, 93.2% (41/44); ferucarbotran-enhanced GRE T2*WI, 88.6% (39/44); Gd-DTPA dynamic-enhanced GRE T1WI, 79.5% (35/44); pre-contrast FSE T2WI with fat suppression, 54.5% (24/44); and pre-contrast GRE T1WI, 34.1% (15/44). In detecting micro-lesions, statistically significant difference was found for Ferucarbotran- enhanced FSE T2WI with fat suppression and GRE T2*WI sequences compared to the other sequences (P < 0.05).CONCLUSION: Ferucarbotran-enhanced FSE T2WI with fat suppression and GRE T2*WI sequences are superior in detecting micro-lesions (< 1 cm) in comparison with plain and Gd-DTPA dynamic-enhanced MR imaging.     

Experimental study on the feasibility and safety of radiofrequency ablation for secondary splenomagely and hypersplenism

AIM: To assess the feasibility and safety of radiofrequency ablation (RFA) in treatment of secondary splenomagely and hypersplenism.METHODS: Sixteen healthy mongrel dogs were randomly divided into two groups, group Ⅰ (n=4) and group Ⅱ (n=12).Congestive splenomegaly was induced by ligation of splenic vein and its collateral branches in both groups. At the end of 3rd week postoperation, RFA in spleen was performed in group Ⅱ via laparotomy, complications of RFA were observed,CT scan was performed and the spleens were obtained.The radiofrequency (RF) thermal lesions and histopathology of spleen were examined regularly.RESULTS: No complication or death was observed in both groups; CT revealed that the splenomegaly lasted over 2 months after ligation of splenic vein; the segmental RF lesions included hyperintense zone of coagulative necrosis and more extensive peripheral hypointense infarcted zone, the latter was called “bystander effect”. The infarcted zone would be absorbed and subsequently disappeared in 4-6 weeks after RFA accompanied with shrinkage of the remnant spleen.The fundamental histopathological changes of splenic lesions caused by RF thermal energy included local coagulative necrosis, peripheral thrombotic infarction zone, subsequent tissue absorption and fibrosis in the zone of thrombotic infarction, the occlusion of vessels in remnant viable spleen,deposition of extensive fibrous protein, and disappearance of congestive splenic sinusoid - “splenic carnification”. Those pathologic changes were underline of shrinkage of spleen.CONCLUSION: It is feasible and safe to perform RFA in spleen to treat experimental splenomegaly and hypersplenism. The RFA could be safely performed clinically via laparotomy or laparoscopic procedure while spleen was strictly separated from surrounding organs.     

原发性肝癌碘油栓塞后磁共振成像表现与病理的对照研究

目的分析原发陆肝癌（HCC）碘油栓塞（TACE）后的磁共振成像（MRI）表现及其病理学基础。方法23例TACE后于术切除的HCC患者，共31个病灶。手术前1周内行MRI检查，包括SE序列T1W1、FSET2W1和FMPSPGR多回合动态增强扫描。术后沿MRI扫描平面作5～10mm层厚肿瘤连续切面和HE染色病理大切片。行MRI影像病理对照研究。结果（1）MRI表现：SE序列上病灶信号多样，且多为不均匀的混杂信号。FMPSPGR平面扫描：3个为不均匀高信号，28个为等低信号。增强早期22个强化，9个无强化。增强晚期6个部分强化。（2）病理结果：2个病灶无明显坏死，6个100％凝固性坏死，其余23个有不同程度坏死。其它病理改变包括肿瘤内坏死伴出血（10个）．纤维间隔形成（5个）、纤维包膜（12个）、炎性细胞浸润（28个）、局限性粘液样变（2个）、玻璃样变（2个）．碘油沉积（6个）。（3）MRI表现与病理对照：T1W1高信号为凝固性坏死伴（或小伴）出血、肿瘤残存；等、低信号为凝固性坏死或肿瘤残存。T2W1高信号为肿瘤残存、凝固性坏死伴出血；等信号为凝固性坏死、少量肿瘤残存、纤维间隔；低信号为凝固性坏死、纤维间隔。增强早期强化为肿瘤残存，无强化为凝固性坏死．出血、纤维间隔或少量肿瘤残仔；增强晚期强化为肿瘤残存、纤维间隔，无强化为肿瘤残存、凝固性坏死、出血。MRI各种信号区均可见炎性细胞浸润。结论（1）由于碘油栓塞后肝癌病灶的不同病理改变导致SE序列上病灶信号多种多样。T2W1低信号有特异性，代表凝固性坏死。（2）多回合动态增强扫描判断肿瘤坏死和残存较SE序列更有优势，增强早期有强化区为肿瘤残存，包膜早期明显强化可提示包膜下残存。（3）MRI能较准确的显示TACE后HCC的肿瘤坏死和残存及评价肝TACE疗效。     

快速多层面干扰梯度回波序列动态增强扫描在小肝癌诊断中的价值评估

目的 分析小肝癌（small hepatocellular carcinoma,SHCC）在自旋回波（SE）序列和快速多面干扰梯度回波（fast multiplanar spoiling recalled,FMPSPGR)序列动态增强扫描中的特征,比较再者对病灶检出敏感性,进一步探讨FMPSPGR在SHCC诊断中的价值。方法 58例SHCC病例行SE序列T1WI,T2WI和FMPSPGR动态增强,比较其检出敏感性和定性准确性,并做统计学处理。结果 58例共检出病灶72个,对SHCC的敏感性依次为FMPSPGR增强＞SE T2WI＞FMPSPGR平扫＞SE T1WI,FMPSPGR增强和后两者之间均有差异,而T2W少FMPSPGR平扫无差异,FMPSPGR平扫和T1WI也有差异,对病灶的定性准确性,FMPSPGR（平扫＋增强）＞SE（T1WI＋T2WI）,再者差异有显著性。结论 FMPSPGR序列在病灶检出和定性方面均优于SE序列,可基本取代之,两者结合可进一步提高敏感性和定性准确性。     

Assessment of cancer cell differentiation in small hepatocellular carcinoma by computed tomography and magnetic resonance imaging

AIM: To study whether cancer cell differentiation in small hepatocellular carcinoma (HCC) can be assessed by computed tomography (CT) and magnetic resonance (MR) imaging. METHODS: We retrospectively evaluated the relationship between cancer cell differentiation in 127 HCC 3 cm or less in diameter (113 patients) and CT and MR images. Images were reviewed in a consensus conference by three authors (SA, TY, and ME). Histopathological diagnosis of HCC was made from liver specimens obtained by sonographically guided biopsy. RESULTS: The degree of histological differentiation of cancer cells was significantly different between HCC that were isodense with liver parenchyma in both artery-dominant and equilibrium phases in contrast-enhanced CT and tumors that were hyperdense in the artery-dominant phase and iso- or hypodense in the equilibrium phase (P = 0.0054), as well as tumors that were iso- or hypodense artery-dominant and hypodense equilibrium (P = 0.0002). Histological differentiation of lesions that were hyperintense in T1-weighted images and hypointense in T2-weighted images differed significantly from those with the opposite MR characteristics (P = 0.0122). In T1-weighted fat-suppression images and T2-weighted images, respectively, the degree of histological differentiation was significant between the hypointense/hyperintense and the hyperintense/hypointense patterns (P < 0.0001), as well as the hyperintense/isointense (P = 0.0296), the hyperintense/hyperintense (P = 0.0434), and the isointense/hyperintense (P = 0.0171). Using these differences an equation was developed that could determine with 76% accuracy whether the tumors were well or less-well differentiated. CONCLUSION: CT and MR imaging patterns were useful in predicting the degree of histological differentiation of cancer cells in HCC.     

实验性肝细胞癌铁铜含量与MR成象的关系

目的初步阐明在MRI常规SE序列,铁、铜元素对肝细胞癌TIWI信号的影响.方法20g/LDEN灌喂Wistar大鼠(n=80),诱癌成功后行常规SE序列T1WI,T2WI扫描,对照组(n=20)不灌喂DEN.扫描后处死动物取肝组织与肝癌组织作HE、普鲁士蓝染色,并测定组织内水、铁、铜含量.结果肝癌与癌周组织含水量无显著差异,肝癌内铁含量低于癌周肝组织,肝癌内的铜含量高于癌周肝组织,在呈低信号的肝癌组织内含铁血黄素明显高于其他信号强度类型,在呈高信号的肝癌组织内明显高于其他信号强度类型的肝癌组织.结论水的含量不是影响肝癌MR表现的主要因素,肝癌内含铁血黄素在SE T1WI呈低信号起作用,肝癌内铜的蓄积对SET1WI呈高信号起作用.     

Histopathological changes after microwave coagulation therapy for patients with hepatocellular carcinoma: review of 15 explanted livers

OBJECTIVES: Microwave coagulation therapy (MCT) is a well established local ablation technique for hepatocellular carcinoma (HCC). However, pathological changes in liver tissue after this therapy have not been well described. We examined the histological changes of HCC after MCT observed in explanted livers in relation to CT findings. METHODS: A total of 15 patients with 18 lesions of HCC underwent MCT and subsequent liver transplantation. Explanted livers were examined macro- and microscopically, and an evaluation of mitochondrial activity of ablated tissue was accomplished by using succinic dehydrogenase (SDH) stain in frozen sections. RESULTS: Of the 18 lesions, 16 were ablated completely and another two had residual tumor. The size of the ablated areas on CT scan corresponded to the macroscopic findings. Histologically the area of ablation was rimmed by a palisading, histiocytic, giant cell, inflammatory reaction associated with fibrotic bands. Coagulative necrosis with faded nuclei and eosinophilic cytoplasm were the predominant findings in the ablated areas. There were also areas in which the tumor cells had cytoplasmic eosinophilia, but nuclei were present and the cells seemed to be viable. On the SDH stain of frozen tissue taken from the edge of the ablated area, SDH activity was negative in both necrotic and nonnecrotic ablated areas. CONCLUSIONS: Most of the treated areas after microwave ablation develop coagulative necrosis accompanied by a foreign body-like inflammatory reaction and fibrosis. Pathologists need to be aware that after this form of therapy, portions of the tumor maintain their native morphological features as if the area is fixed, but their cellular activity is destroyed.     

Hepatocellular carcinoma: magnetic resonance imaging after ultrasonically guided percutaneous alcohol treatment. Preliminary report

Percutaneous alcohol injection (PAI) is reported as a safe, inexpensive and effective method of treatment of small HCC in severely ill patients. Nevertheless, residual cancer can persist after treatment and multiple bioptic manoeveurs are needed to ascertain the actual completeness of treatment. In two cases of HCC treated by ethanol injections, MRI on T2 weighted sequences showed a characteristic change from the previous hyperintense or isointense signal to a hypointense one. This MRI pattern, quite different from the usual HCC features, was correlated to the histologic findings of complete coagulative necrosis of the tumoural mass. Further observations are needed to assess reproducibility and specificity of this finding and the MRI pattern needs to be evaluated also in unsatisfactory percutaneous alcohol treatment of HCC in order to demonstrate that cases with persistent neoplastic tissue display a different pattern. If our report should be confirmed, MRI might be a not invasive tool in evaluating the effectiveness of PAI in patients at risk for multiple histologic samplings. Furthermore MRI could be very useful in assessing the degree and extent of tissutal changes in response to local therapy also after the tumour and its margin are masked by US guided ethanol injections.     

Differentiation between dysplastic nodule and early-stage hepatocellular carcinoma: The utility of conventional MR imaging

AIM:To elucidate the variety of ways early-stage hepatocellular carcinoma(HCC)can appear on magnetic resonance(MR)imaging by analyzing T1-weighted,T2-weighted,and gadolinium-enhanced dynamic studies.METHODS:Seventy-three patients with well-differentiated HCC(wHCC)or dysplastic nodules were retrospectively identified from medical records,and new histological sections were prepared and reviewed.The tumor nodules were categorized into three groups:dysplastic nodule(DN),wHCC compatible with Edmondson-Steiner grade I HCC(w1-HCC),and wHCC compatible with Edmondson-Steiner gradeⅡHCC(w2-HCC).The signal intensity on pre-contrast MR imaging and the enhancing pattern for each tumor were recorded and compared between the three tumor groups.RESULTS:Among the 73 patients,14 were diagnosed as having DN,40 were diagnosed as having w1-HCC,and 19 were diagnosed as having w2-HCC.Hyperintensity measurements on T2-weighted axial images(T2WI)were statistically significant between DNs and wHCC(P=0.006)and between DN and w1-HCC(P=0.02).The other imaging features revealed no significant differences between DN and wHCC or between DN and w1-HCC.Hyperintensity on both T1W out-phase imaging(P=0.007)and arterial enhancement on dynamic study(P=0.005)showed statistically significant differences between w1-HCC and w2-HCC.The other imaging features revealed no significant differences between w1-HCC and w2-HCC.CONCLUSION:In the follow-up for a cirrhotic nodule,increased signal intensity on T2WI may be a sign of malignant transformation.Furthermore,a noted loss of hyperintensity on T1WI and the detection of arterial enhancement might indicate further progression of the histological grade.     

小肝癌MR信号值与微血管侵犯相关性分析

目的分析小肝癌MR信号值与微血管侵犯(microvascular-invasion,MVI)的相关性。方法收集整理2010年12月至2019年1月解放军总医院第五医学中心小肝癌手术切除且于术前1周至1个月内行MR动态增强扫描检查的患者33例,根据病理诊断分为微血管侵犯组和非微血管侵犯组,进一步分为甲胎蛋白(AFP)阳性组和阴性组,测量并计算术前MR图像T1WI、T2WI、DWI序列及动态增强扫描动脉期、门脉期、延迟期病变信号值与相邻肝背景信号值的比值。结果33例患者中微血管侵犯22例,非微血管侵犯组11例;AFP阳性组17例,AFP阴性组16例。AFP阳性病例微血管侵犯与非微血管侵犯组间动脉期强化和延迟期强化信号特征差异有统计学意义(P<0.05),而T1WI序列、T2WI、DWI序列病变信号特征差异无统计学意义(P<0.05);AFP阴性病例T1WI序列、T2WI、DWI序列及动态增强扫描各期病变信号特征差异无统计学意义(P<0.05)。结论微小肝癌MR动态增强扫描病变强化特征可用于预测病变是否存在微血管侵犯。