磁共振磁敏感加权成像在肝硬化结节多步癌变中的临床应用

肝癌早期发现,早期治疗,明显提高5年生存率。肝硬化患者,绝大部分均经历肝硬化结节多步癌变的过程,即由再生结节发展为异型增生结节,其中高分化异型增生结节发展为癌变结节后（早期肝癌）,再发展为小肝癌,小肝癌最后发展成进展期或晚期肝癌。上述结节的一系列变化过程中,其结节内内源性铁逐步廓清,本文重点介绍利用磁共振磁敏感加权成像（SWI）技术观察结节中内源性铁变化情况,同时结合常规MRT2W1、弥散加权成像（DWI）和动态增强等技术,提高识别肝硬化背景下的癌变／早期肝癌结节能力,从而对进一步提高早期小肝癌的诊疗,具有更重要的临床意义。     

Serum amyloid A and C‐reactive protein positive nodule in alcoholic liver cirrhosis,hard to make definite diagnosis

We describe a case of serum amyloid A (SAA) and C‐reactive protein (CRP) positive nodule detected by immunohistochemical analysis in a 37‐year‐old woman with alcohol‐related cirrhosis. Imaging studies at first admission pointed to hepatocellular carcinoma (HCC), a dysplastic nodule, an inflammatory pseudotumor or focal nodular hyperplasia (FNH). Ultrasonography‐guided biopsy in Segment 2 showed minimal atypical changes, except for a slight increase in cell density and micronodular cirrhosis in the non‐nodular portion. gadolinium‐ethoxybenzyl‐diethylenetriamine pentaacetic acid‐enhanced magnetic resonance imaging carried out after a year and a half revealed hypervascularity in the arterial phase and isointensity in the hepatobiliary phase. Three years thereafter, however, the imaging displayed a change from isointensity to a defect in the hepatobiliary phase, and the nodule demonstrated minimal histological atypia. Immunohistochemical staining of the nodule was positive for SAA, CRP, liver fatty acid‐binding protein and glutamine synthetase, but negative for β‐catenin, heat shock protein 70 and Glypican 3. Organic anion transporter (OATP)8 staining was weaker in the nodule than in the non‐nodular portion of the alcohol‐related micronodular cirrhosis. The nodule was diagnosed as an SAA and CRP positive nodule, and HCC was ruled out. Despite the change from isointensity to a defect in the hepatobiliary phase, no evidence of HCC was found in the biopsy specimen. The change may be explained more by the weak OATP8 staining compared with that of alcohol‐related liver cirrhosis than by malignant transformation into HCC.     

Scirrhous hepatocellular carcinoma displaying atypical findings on imaging studies

We describe a 15-mm scirrhous hepatocellular carcinoma （HCC） in a 60-year-old man with B-type cirrhosis. Ultrasound disclosed a 15-mm hypoechoic nodule in segment 7. Contrast-enhanced US revealed heterogeneous, not diffuse, hypervascularity in the early phase and a defect in the Kupffer phase.Contrast-enhanced computed tomography （CT） revealed a heterogeneous hypervascular nodule in the early phase and a low-density area in the late phase.Magnetic resonance imaging （MRI） revealed iso- to hypointensity at T1 and high intensity at T2-weighted sequences. Contrast-enhanced MRI also revealed a heterogeneous hypervascular nodule in the early phase and washout in the late phase. Super-paramagnetic iron oxide-MRI revealed a hvoerintense nodule. CT during hepatic arteriography and CT during arterial portography revealed heterogeneous hyperattenuation and a perfusion defect, respectively. Based on these imaging findings the nodule was diagnosed as a mixed well-differentiated and moderately-differentiated HCC.Histologically, the nodule was moderately-differentiated HCC characterized by typical cytological and structural atypia with dense fibrosis. Immunohistochemically,the nodule was positive for heterochromatin protein 1 and alpha-smooth muscle actin, and negative for cytokeratin 19. From the above findings, the nodule was diagnosed as scirrhous HCC. Clinicians engaged in hepatology should exercise caution with suspected scirrhous HCC when imaging studies reveal atypical findings, as shown in our case on the basis of chronic liver disease.     

Diagnosis of liver nodules within and outside screening programs

Evaluation of a liver nodule detected with ultrasound includes the recovery of a detailed medical history, a physical exam, appropriate contrast imaging examinations and, in selected cases, histopathology. In this setting, identification of liver disease accompanying a liver nodule helps distinction between benign nodules and metastatic malignant nodules from primary liver cancer, as recommended by scientific liver societies. Diagnostic algorithms for a liver nodule in patients with liver disease involve contrast CT scan, magnetic resonance imaging or contrast enhanced ultrasounds to show the typical neoplastic pattern of early arterial hyperenhancement wash-in followed by hypoenhancement in the late portal phase wash out. The flow charts developed by western societies utilize the discriminant criterion of tumor size i.e. the radiological diagnosis being endorsed in a nodule equal or greater than 1 cm whereas eastern societies rely on the recognition of a typical vascular pattern of the node, independently of size. Differential diagnosis should be obtained to differentiate liver related nodules like regenerative macronodules (more than 20% of the cases) and the less frequent intrahepatic cholangiocarcinoma (~2% of the cases) from liver disease unrelated nodules like hemangioma (~4%), neuroendocrine metastatic nodules and focal nodular hyperplasia. In patients without liver disease, the most common liver nodules in the liver are hemangioma (~1.5%), focal nodular hyperplasia (0.03%) and hepatocellular adenoma (up to 0.004% in long term users of oral contraceptives). Optimization of management of patients with a liver nodule requires establishment of a multidisciplinary clinic.     

Recent advances in the diagnosis of hepatocellular carcinoma

In the last decade, new imaging techniques have become available, offering the possibility of investigating contrast perfusion of liver nodules in cirrhosis. It is now accepted that a non-invasive diagnosis of hepatocellular carcinoma (HCC) can be established based on the vascular pattern, obtained with pure blood pool contrast agents. The diagnostic pattern includes: hypervascularity in the arterial phase (15–35 s after contrast injection), consisting in a contrast signal in the nodule greater than in the surrounding parenchyma, followed by contrast wash out, which leads the nodule to show the same, or, more specifically, a lower contrast signal, than the surrounding parenchyma in the portal and late phases (>40 s after injection). Such a pattern can be obtained not only by computed tomography or magnetic resonance imaging, but also by contrast-enhanced ultrasonography, most simply with real-time low mechanical index harmonic imaging ultrasound equipment with second-generation ultrasound contrast agents. The risk of false-positive diagnosis of malignancy isnearly abolished when the functional vascular pattern is not the only feature, but is superimposed on a nodule visible also without contrast. One single contrast imaging technique may suffice to make a diagnosis of HCC if the nodule is >1 cm in diameter and has developed during a surveillance program. Other types of contrast agents, such as those taken up by the reticular-endothelial system cells, may offer additional diagnostic clues, but definitive evidence of their efficacy is still to be produced. In conclusion, contrast-enhanced imaging techniques now offer the possibility of a non-invasive diagnosis of HCC in a large number of cases, reducing the need of invasive investigations, such as ultrasound-guided biopsy or angiography.     

Focal nodular hyperplasia-like nodule with reduced expression of organic anion transporter 1B3 in alcoholic liver cirrhosis

We report a patient with alcoholic liver cirrhosis who had a 15 mm focal nodular hyperplasia (FNH)-like nodule in the liver. This FNH-like nodule was diagnosed as hepatocellular carcinoma (HCC) mainly based on hypervascularity during the hepatic arterial phase, washout pattern during the equilibrium phase and low signal intensity during the hepatobiliary phase in gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI; it was surgically resected. Its histology exhibited hepatocyte hyperplasia, fibrous septa containing unpaired small arteries accompanied by reactive bile ductules, remarkable iron deposits and sinusoidal capillarization, and was compatible with the diagnosis of an FNH-like nodule. When we analyzed the images of the present nodule retrospectively, low signal intensity on in-phase and isosignal intensity on opposed-phase T1-weighted MRI may have reflected iron deposits in the FNH-like nodule. In addition, a low signal intensity on T2-weighted MRI and no detection in diffusion-weighted MRI may help in distinguishing FNH-like nodules from HCC, since these image findings are inconsistent with typical HCC. Immunohistochemical analysis revealed a markedly reduced expression of organic anion transporter (OATP) 1B3 in this nodule, which implied decreased Gd-EOB-DTPA uptake by hepatocytes and accounted for the low signal intensity during the hepatobiliary phase on Gd-EOB-DTPA-enhanced MRI. To the best of our knowledge this is the first report in which an FNH-like nodule was assessed for OATP1B3 expression.     

Noninvasive imaging of hepatocellular carcinoma: From diagnosis to prognosis

Hepatocellular carcinoma(HCC) is the most common primary liver cancer and a major public health problem worldwide. Hepatocarcinogenesis is a complex multistep process at molecular, cellular, and histologic levels with key alterations that can be revealed by noninvasive imaging modalities. Therefore, imaging techniques play pivotal roles in the detection, characterization, staging, surveillance, and prognosis evaluation of HCC. Currently, ultrasound is the first-line imaging modality for screening and surveillance purposes. While based on conclusive enhancement patterns comprising arterial phase hyperenhancement and portal venous and/or delayed phase wash-out, contrast enhanced dynamic computed tomography and magnetic resonance imaging(MRI) are the diagnostic tools for HCC without requirements for histopathologic confirmation. Functional MRI techniques, including diffusion-weighted imaging, MRI with hepatobiliary contrast agents, perfusion imaging, and magnetic resonance elastography, show promise in providing further important information regarding tumor biological behaviors. In addition, evaluation of tumor imaging characteristics, including nodule size, margin, number, vascular invasion, and growth patterns, allows preoperative prediction of tumor microvascular invasion and patient prognosis. Therefore, the aim of this article is to review the current state-of-the-art and recent advances in the comprehensive noninvasive imaging evaluation of HCC. We also provide the basic key concepts of HCC development and an overview of the current practice guidelines.     

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.     

Large regenerative nodule perfused by the portal vein

In a 42-year-old Japanese woman with esophageal varices, abdominal ultrasound (US) demonstrated a hyperechoic lesion 3 cm in diameter in segment 4 (S4). This nodular lesion had high intensity on T1-weighted magnetic resonance imaging (MRI), low intensity on T2, and very high intensity on superparamagnetic iron oxide (SPIO) enhanced MRI. Angiography showed sparse distribution of arterial branches and dense distribution of portal branches in S4. Meandering, thin arteries were seen in the peripheral area of the right lobe. The second branches of the portal vein were hardly visualized anywhere in the liver. Computed tomography arterioportography (CTAP) revealed portal blood flow dominance in this nodular lesion. There was no evidence of ischemic liver damage, such as thromboembolic episodes, laboratory data of liver damage, coagulation abnormalities etc. Therefore this abnormality was more likely to be caused by anomalous changes than thrombotic changes. Needle biopsy revealed no atypical cells. Two years later, the nodule size was reduced to 1.9 cm, showing its benign nature. Based on these findings, this lesion was classified as a new type of large regenerative nodule (LRN) associated with anomalies in the portal veins and arteries. This is the first report of an LRN of this size in which portal vein perfusion was dominant. Moreover, this lesion was difficult to differentiate from hepatocellular carcinoma (HCC) by imaging. Analysis of the images and pathological features of this case would contribute to a better understanding of the pathogenesis of nodular lesions of the liver.     

Hepatocellular carcinoma with extensive peliotic change

Peliosis hepatis is a rare lesion histologically characterized by multiple cavities representing dilated sinusoids filled with blood in the liver. Although it has been observed in the liver parenchyma in association with several diseases and medications, there are few reports of nodules of hepatocellular carcinoma (HCC) showing extensive peliotic change. We describe a case of HCC showing extensive peliotic change in the cancer nodule. A 73-year-old man with a liver tumor was referred to our hospital for further investigation. Abdominal ultrasonography revealed an 8-cm hyperechoic lesion with a halo and mosaic pattern in segment 8 (S8) of the liver. Dynamic magnetic resonance imaging of the liver showed early irregular enhancement of the peripheral part of the lesion, and the effect persisted into the late phase, spreading into the central part of the nodule. Hepatic arteriography showed the “cotton–wool” sign, usually observed in cavernous hemangiomas. Fine-needle aspiration biopsy revealed the diagnosis of HCC. Anterior sectionectomy of the liver was conducted. Histological examination of the resected specimen showed that the tumor was a well-differentiated HCC with extensive dilated sinusoid-like structures in the main portion of the nodule, suggestive of peliotic change.     

MRI检查及ADC值对肝腺瘤诊断的意义

目的分析MRI检查及ADC值对肝腺瘤诊断的意义。方法以21例经病理检查证实的肝腺瘤患者为研究对象,观察患者术前和活检诊断结果、MRI表现,计算表观扩散系数(ADC),对比以上检查与病理检查结果。结果 2例患者存在肝硬化表现,1例患者9个病灶,5例2个病灶,15例患者为单个病灶。26个病灶内脂质成分多,8个病灶脂质成分少。术前19例患者确诊为良性肝腺瘤,2例考虑为局灶性结节增生。18例病灶直径3 cm,10例病灶直径在3~5 cm,6例病灶直径5 cm。T1WI信号低信号30例,高信号4例;T2WI扫描低信号11例,高信号23例;Gd-DTPA增强扫描,动脉期病灶信号明显强化,门静脉期病灶低信号12例,高信号22例;延迟期扫描病灶低信号12例,高信号22例;DWI扫描病灶低信号21例,高信号13例。可见假包膜样强化病灶14例,假包膜样强化未明确20例。34例病灶平均ADC值为(1.704±0.330)×10~(-3)mm~2/s,病灶周边正常肝实质ADC值为(1.357±0.214)×10~(-3)mm~2/s,病灶ADC值与病灶周边肝实质ADC值比值1。结论 MRI检查联合病灶ADC值测量可为诊断肝腺瘤提供更为准确的参考依据,提高临床诊断肝腺瘤的准确率。     

MR with Gd-EOB-DTPA in assessment of liver nodules in cirrhotic patients

To date the imaging diagnosis of liver lesions is based mainly on the identification of vascular features, which are typical of overt hepatocellular carcinoma(HCC), but the hepatocarcinogenesis is a complex and multistep event during which, a spectrum of nodules develop within the liver parenchyma, including benign small and large regenerative nodule(RN), low-grade dysplastic nodule(LGDN), high-grade dysplastic nodule(HGDN), early HCC, and well differentiated HCC. These nodules may be characterised not only on the basis of their respective different blood supplies, but also on their different hepatocyte function. Recently, in liver imaging the introduction of hepatobiliary magnetic resonance imaging contrast agent offered the clinicians the possibility to obtain, at once, information not only related to the vascular changes of liver nodules but also information on hepatocyte function. For this reasons this new approach becomes the most relevant diagnostic clue for differentiating low-risk nodules(LGDN-RN) from highrisk nodules(HGDN/early HCC or overt HCC) and consequently new diagnostic algorithms for HCC have been proposed. The use of hepatobiliary contrast agents is constantly increasing and gradually changing the standard of diagnosis of HCC. The main purpose of this review is to underline the added value of Gd-EOB-DTPA in early-stage diagnoses of HCC. We also analyse the guidelines for the diagnosis and management of HCC, the key concepts of HCC development, growth and spread and the imaging appearance of precursor nodules that eventually may transform into overt HCC.     

Multistep hepatocarcinogenesis from a dysplastic nodule to well-differentiated hepatocellular carcinoma in a patient with alcohol-related liver cirrhosis

We describe a rare case of the transformation of a dysplastic nodule into well-differentiated hepato- cellular carcinoma (HCC) in a 56-year-old man with alcoholrelated liver cirrhosis. Ultrasound (US) disclosed a 10 mm hypoechoic nodule and contrast enhanced US revealed a hypovascular nodule, both in segment seven. US-guided biopsy revealed a high-grade dysplastic nodule characterized by enhanced cellularity with a high N/C ratio, increased cytoplasmic eosinophilia, and slight cell atypia. One year later, the US pattern of the nodule changed from hypoechoic to hyperechoic without any change in size or hypovascularity. US-guided biopsy revealed well-differentiated HCC of the same features as shown in the first biopsy, but with additional pseudoglandular formation and moderate cell atypia. Moreover, immunohistochemical staining of cyclase- associated protein 2, a new molecular marker of well- differentiated HCC, turned positive. This is the first case of multistep hepatocarcinogenesis from a dysplastic nodule to well-differentiated HCC within one year in alcohol-related liver cirrhosis.     

Role and limitation of FMPSPGR dynamic contrast scanning in the follow—up of patients with hepatocellular carcinoma treated by TACE

AIM：To evaluate the role and limitation of fast multiplanar spoiled gradient-recalled(FMPSPGR)MRdynamiccontrast scanning in the follow-up of patients with HCCtreated by transarterial chemoembolization(TACE).METHODS:Twenty-two patients with 24HCClesions confirmed by biopsy or surgical resection underwent MR imaging in 4-9wks after TACEwith a superconducting 1.5TMR scanner,including SE T1WI,T2WIand FMPSPGR dynamic contrast scanning.The signal intensities of all lesions on SET1WI,T2WIand the enhancement patterns on FMPSPGRdynamic contrast scanning were observed,and the comparison was made between MRI findings and pathological results in all the casese.RESULTS:Of the 24lesions,the signal intensities were various on SET1WIand T2WI.OnT1WI,13lesions appeared as hyperintense,4 lesions were isointense and the other 7lesions were hypointensese,Histologically.Hyperintense lesions showed on T1WI were viable tumor or hemorrhage;isointensities were coagulative necrosis or inflammatory infiltration;hypointensities were tumor,liquified necrosis,coagulative necrosis or inflammatory infiltration.OnT2WI,15lesions appeared as hyperintense,3lesions were isointense and the other 6lesions were hypointensese,Hyperintense lesions shower on T2WI were residuals of viable tumor,hemorrhage,liquefied necrosis or inflammatory infiltration;isointense lesions were residuals of viable tumor or inflammatory infiltration;hypointense lesions were coagulative necrosis.On FMPSPGR dynamic contrast scanning,18 of the 24lesions enhanced on early-phase dynamic scanning corresponding to residuals of viable tumor and the other 6lesions had no enhancement at this phase because complete necrosis were seen in the histologic examination.On delayed-phase dynamic scanning,6lesions had permanent enhancement appeared as inhomogeneous hyperintensity and both residuals of viable tumor and inflammatory infiltration were found by histologic examination,18 lesions were hypointense at this phase and 8of them coexisted with peripheral ring-like enhancement of the lesions resulting from viable tumors or inflammatory infiltration.CONCLUSION:FMPSPGR MR dynamic contrast scanning can reflect the pathologic changes of HCCtreated by TACE.Especially.early-phase dynamic scanning can evaluate accurately residuals of viable tumor and necrosis in HCClesions.FMPSPGR dynamic contrast scanning is useful in the follow-up of patients with HCC treated by TACEcombined with SET1WIand T2WI,but is is difficult to differentiate peripheral viable tumors from inflammatory infiltration.     

Focal nodular hyperplasia-like lesion with venous washout in alcoholic liver cirrhosis

A case of 22 mm hypervascular nodule in segment two of the liver but without hepatitis B or C virus infection in a 32-year-old Japanese woman with a history of alcohol abuse is presented. Imaging studies such as contrast-enhanced ultrasound, computed tomography and magnetic resonance imaging showed hypervascularity in the early phase and venous washout in the late phase. Histologically, stellate scar-like fibrous septa, pericellular fibrosis, fatty change, neutrophilic infiltration, slight increase of cell density, and diffuse capillarization of the sinusoids together with small unpaired arteries were observed. The nodule was diagnosed as focal nodular hyperplasia-like lesion in alcoholic liver cirrhosis.     

Hepatocellular carcinoma: detection with diffusion-weighted versus contrast-enhanced magnetic resonance imaging in pretransplant patients

This study evaluates the performance of diffusion-weighted magnetic resonance imaging (DWI) for the detection of hepatocellular carcinoma (HCC) in pre-liver transplantation patients, compared and combined with contrast-enhanced T1-weighted imaging (CET1WI), using liver explant as the standard of reference. We included 52 patients with cirrhosis (40 men, 12 women; mean age, 56 years) who underwent DWI and CET1WI within 90 days of liver transplantation. Magnetic resonance images were analyzed for HCC detection in three separate sessions by two independent observers: DWI images (DW-set), CET1WI (CE-set), and all images together (All-set). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), per-patient accuracy, and per-lesion PPV were calculated for each image set. A total of 72 HCCs were present in 33 patients at explant (mean size, 1.5 cm [range, 0.3-6.2 cm]). Per-patient sensitivity and NPV of CE-set were significantly higher than those of DW-set when using pooled data between observers (P = 0.02 and 0.03, respectively), whereas specificity, PPV, and accuracy were equivalent. Per-lesion sensitivity was significantly higher for CE-set versus DW-set (59.0% versus 43.8%; P = 0.008, pooled data from two observers). When stratified by lesion size, the difference was significant only for lesions with a size between 1 and 2 cm (42.0% for DW-set versus 74.0% for CE-set; P = 0.001). The addition of DWI to CET1WI improved sensitivity for the more experienced observer. CONCLUSION: DWI is outperformed by CET1WI for detection of HCC, but represents a reasonable alternative to CET1WI for detection of HCC with a size above 2 cm. The addition of DWI to CET1WI slightly increases the detection rate.     

Contrast imaging techniques to diagnose hepatocellular carcinoma in cirrhotics outside regular surveillance

Introduction and aimThe American Association for the Study of the Liver (AASLD) recommends contrast computerized tomography (CT-scan) and magnetic resonance (MRI) to diagnose hepatocellular carcinoma (HCC) arising in cirrhotic patients under semiannual surveillance with abdominal ultrasound (US). A US guided fine needle biopsy (FNB) serves the same purpose in radiologically undiagnosed tumors and incidentally detected nodules in cirrhotics outside surveillance. In this population, we evaluated the performance of radiological diagnosis of HCC according to 2010 AASLD recommendations.Materials and methodsAll cirrhotic patients with a liver nodule incidentally detected by US were prospectively investigated with a sequential application of CT-scan/MRI examination and a FNB.ResultsBetween 2011 and 2015, 94 patients (mean age 67 years) had a liver nodule (total 120) detected by US in the context of histologically confirmed cirrhosis. Mean nodules diameter was 40 (10–160) mm, 87 (73%) <5 cm. At histology, 84 (70%) nodules were HCC, 8 (7%) intrahepatic cholangiocarcinoma, 6 (5%) metastases, 2 (2%) neuroendocrine tumors and 20 (16%) benign lesions. Hyperenhancement in arterial phase followed by wash-out in venous phases on at least one radiological technique was demonstrated in 62 nodules (61 HCC, 1 high grade dysplastic nodule), with a specificity of 97% (IC95%: 85–100%), sensitivity 73% (IC95%: 62–81%) and diagnostic accuracy 80%, being 64% for ≥5 cm HCC. Sensitivity of AFP >200 ng/mL was 12% (IC95%: 6–23%).ConclusionA single contrast imaging technique showing a typical contrast pattern confidently identifies HCC also in cirrhotic patients with an incidental liver nodule, thereby reducing the need for FNB examinations.     

Solitary Necrotic Nodules of the Liver: Histology and Diagnosis With CT and MRI

Background

A solitary necrotic nodule (SNN) of the liver is an uncommon lesion, which is different from primary and metastatic liver cancers.

Objectives

To analyze the classification, CT and MR manifestation, and the pathological basis of solitary necrotic nodule of the liver (SNN) in order to evaluate CT and MRI as a diagnosing tool.

Patients and Methods

This study included 29 patients with liver SNNs, out of which 14 had no clinical symptoms and were discovered by routine ultrasound examinations, six were found by computed tomography (CT) due to abdominal illness, four had ovarian tumors, and five had gastrointestinal cancer surgeries, previously. Histologically, these SNNs can be divided into three subtypes, i.e., type I, pure coagulation necrosis (14 cases); type II, coagulation necrosis mixed with liquefaction necrosis (five cases); and type III, multi-nodular fusion (10 cases). CT and magnetic resonance imaging (MRI) patterns were shown to be associated with SNN histology. All patients were treated surgically with good prognosis.

Results

CT and MRI appearance and correlation with pathology types: three subtypes of lesions were hypo-density on both pre contrast and post contrast CT, 12 lesions were found the enhanced capsule and 1 lesion of multi- nodular fusion type showed septa enhancement. The lesions were hypo-intensity on T2WI and the lesions of type II showed as mixed hyperintensity on T2WI. The capsule showed delayed enhancement in all cases, and all lesions of multi- nodular fusion type showed delayed septa enhancement on MR images. 15 cases on CT were misdiagnosed and Four cases on MRI were misdiagnosed and the accuracy of CT and MRI were 48.3% and 86.2% respectively.

Conclusions

In conclusion, CT and MRI are useful tools for SNN diagnosis.     

Diagnosis of hepatic nodules 20 mm or smaller in cirrhosis: Prospective validation of the noninvasive diagnostic criteria for hepatocellular carcinoma

This study prospectively evaluates the accuracy of contrast-enhanced ultrasound (CEUS) and dynamic magnetic resonance imaging (MRI) for the diagnosis of nodules 20 mm or smaller detected during ultrasound (US) surveillance. We included 89 patients with cirrhosis [median age, 65 years; male 53, hepatitis C virus 68, Child-Pugh A 80] without prior hepatocellular carcinoma (HCC) in whom US detected a small solitary nodule (mean diameter, 14 mm). Hepatic MRI, CEUS, and fine-needle biopsy (gold standard) (FNB) were performed at baseline. Non-HCC cases were followed (median 23 months) by CEUS/3 months and MRI/6 months. FNB was repeated up to 3 times and on detection of change in aspect/size. Intense arterial contrast uptake followed by washout in the delayed/venous phase was registered as conclusive for HCC. Final diagnoses were: HCC (n = 60), cholangiocarcinoma (n = 1), and benign lesions (regenerative/dysplastic nodule, hemangioma, focal nodular hyperplasia) (n = 28). Sex, cirrhosis cause, liver function, and alpha-fetoprotein (AFP) levels were similar between HCC and non-HCC groups. HCC patients were older and their nodules significantly larger (P < 0.0001). First biopsy was positive in 42 of 60 HCC patients. Sensitivity, specificity, and positive and negative predictive values of conclusive profile were 61.7%, 96.6%, 97.4%, and 54.9%, for MRI, 51.7%, 93.1%, 93.9%, and 50.9%, for CEUS. Values for coincidental conclusive findings in both techniques were 33.3%, 100%, 100%, and 42%. Thus, diagnosis of HCC 20 mm or smaller can be established without a positive biopsy if both CEUS and MRI are conclusive. However, sensitivity of these noninvasive criteria is 33% and, as occurs with biopsy, absence of a conclusive pattern does not rule out malignancy. These results validate the American Association for the Study of Liver Disease (AASLD) guidelines.     

A case of focal nodular hyperplasia presenting corona enhancement on single-level dynamic CT during hepatic arteriography]

A hepatic nodule was detected in segment 5/6 on abdominal US study in a 28 year-old male. The nodule was 7cm in diameter and the early phase of contrasted US, CT and MRI images showed spoke-wheel like vessels radiating from the center. No defect images were observed on postvascular phase contrasted US and SPIO MRI, which indicated the presence of Kupffer cells in the nodule. The nodule was diagnosed as a focal nodular hyperplasia (FNH) based on histological findings. The late phase of single level dynamic CT during hepatic arteriography (CTHA) showed corona enhancement of the nodule, which is considered to be characteristic of hypervascular metastatic liver tumors, hyperplastic nodules and HCCs. In our case, the drainage flow from the nodule may have been visualized as corona enhancement via the pathway from the sinusoid in the nodular periphery to the one in the adjacent and contiguous parenchyma.