The current status of imaging diagnosis of hepatocellular carcinoma

Ultrasound-New Techniques Are Extending the Applications

BACKGROUND

Sonography is often the first imaging procedure to be used in diagnostic investigation of the abdomen. The aim of this article is to provide a new interdisciplinary overview of recent groundbreaking advances in this modality.

METHODS

A selective survey of the literature in PubMed was conducted. The literature search was carried out in 2021-2022 and included publications over the period 2004-2022.

RESULTS

The novel sonographic software techniques can be divided into algorithms that deal with conventional B-scan optimization and new programs that extend the scope of sonographic examination. The latter include elastography, contrast-enhanced sonography, and image fusion in combination with other cross-sectional imaging modalities. Elastography can be used to assess the presence of steatosis, fibrosis, or cirrhosis in patients with liver disease. One study reported diagnostic accuracy of 84-87% for the diagnosis of significant fibrosis (F2), 89-91% for the diagnosis of severe fibrosis (F3), and 92-93% for the diagnosis of liver cirrhosis (F4). Contrast-enhanced sonography is used for evaluation of tumors and trauma. A prospective multicenter study found sensitivity of 95.8% for the characterization of malignant lesions and specificity of 83.1% for benign lesions. Image fusion has the potential to improve the diagnostic assessment of parenchymatous organs, vascular conditions, and the prostate.

CONCLUSION

With continuous improvement of the B-scan and the development of high-frequency probes and novel investigation techniques, sonography has become established as an increasingly autonomous examination procedure.

Value of precontrast and portal venous phases for evaluating atypical hepatocellular carcinoma mimicking arterioportal shunt

PURPOSE

To evaluate the value of precontrast phase (PP) and portal venous phase (PVP) for differentiation of small hypervascular hepatocellular carcinomas (HCCs) without delayed washout from arterioportal (AP) shunts in high-risk patients of HCC.

METHODS

A total of 122 lesions (73 AP shunts and 49 HCCs) detected on quadriphasic CT in 101 patients with chronic liver disease were analyzed. All lesions (≤2 cm) showed arterial enhancement and isodensity on delayed phase (DP) with exclusion of typical features of AP shunts. Lesion morphologic features (size, location, shape, margin) on biphasic CT (arterial phase and DP), Alpha-fetoprotein (AFP) values and coexistent HCC were evaluated. The qualitative and quantitative analyses of lesion attenuation on quadriphasic CT were performed. Diagnostic performances for prediction of AP shunts over HCC were compared among the biphasic CT, triphasic CT (adding PP or PVP) and quadriphasic CT.

RESULTS

In multivariate analysis, the presence of concomitant HCC (p = 0.0005, odds ratio [OR] = 0.11), visual hypodensity on PP (p = 0.0004, OR = 17.72) and visual hyperdensity on PVP (p = 0.0003, OR = 0.051) were independent predictors for HCCs rather than AP shunts. Additional review of PP and PVP revealed significantly improved diagnostic performance yielding the highest diagnostic performance.

CONCLUSIONS

Hypodensity on PP and hyperdensity on PVP are significant predictive features in differentiating atypical small hypervascular HCC from AP shunts in patients with high-risk of HCC. Careful evaluation of the PP and PVP may reduce underdiagnosis and lead to earlier diagnosis of atypical small HCCs.

Ramucirumab as a second line therapy for advanced HCC: a significant achievement or a wasted opportunity for personalised therapy?

The second line treatment of hepatocellular carcinoma (HCC) has recently become an exciting area of interest since new emerging options have demonstrated survival benefits versus placebo. Unfortunately, predictive biomarkers are unavailable for these treatments. Ramucirumab, a monoclonal antibody against VEGFR-2, has demonstrated overall survival superiority against placebo as a second line therapy for patients with AFP > 400 ng/ml in the recent REACH-2 trial. This review will provide the current updated knowledge regarding the HCC cancerogenesis and angiogenic VEGF/VEGFR-2 pathways and the clinical development of ramucirumab in advanced HCC. This study will also critically assess the gaps in a previous negative phase III trial that tested other potentially useful treatments and suggest ways to modernise clinical trials and personalise therapy for advanced HCC.

Classification of Liver Diseases Based on Ultrasound Image Texture Features

This paper discusses using computer-aided diagnosis (CAD) to distinguish between hepatocellular carcinoma (HCC), i.e., the most common type of primary liver malignancy and a leading cause of death in people with cirrhosis worldwide, and liver abscess based on ultrasound image texture features and a support vector machine (SVM) classifier. Among 79 cases of liver diseases including 44 cases of liver cancer and 35 cases of liver abscess, this research extracts 96 features including 52 features of the gray-level co-occurrence matrix (GLCM) and 44 features of the gray-level run-length matrix (GLRLM) from the regions of interest (ROIs) in ultrasound images. Three feature selection models—(i) sequential forward selection (SFS), (ii) sequential backward selection (SBS), and (iii) F-score—are adopted to distinguish the two liver diseases. Finally, the developed system can classify liver cancer and liver abscess by SVM with an accuracy of 88.875%. The proposed methods for CAD can provide diagnostic assistance while distinguishing these two types of liver lesions.

Studying the frequency of aberrant DNA methylation of APC, P14, and E-cadherin genes in HCV-related hepatocarcinogenesis

BACKGROUND

Data about the molecular pathogenesis of hepatitis C-related hepatocellular carcinoma (HCC) are still challenging.

OBJECTIVES

Therefore, we tried to investigate the epigenetic study of three nominated genes (APC, P14, and E-cadherin) in the pathogenesis of HCV-related HCC in Egyptian.

METHODS

Between March 2016 and March 2017, the DNA methylation, and quantification using (epigenetic ELISA kit) for E-cadherin, APC, and P14 genes were studied in three groups of patients: HCV related liver cirrhosis without HCC group (LC-group; n= 20), HCC on top of HCV-related cirrhosis (HCC-group; n= 20), and a third apparently healthy control group (control-group; n= 10).

RESULTS

E-cad methylation showed non-significant differences between groups. P14 methylation was occurred only in HCC-group (45%). APC methylation was the highest in HCC group (70%). Methylation level was high in HCC group in comparison to both LC and control groups (P< 0.001). DNA methylation at a cutoff point > 2.9 ng/ml predicts HCC in LC-group with 90% sensitivity and 80% specificity and at level > 2.3 ng/ml had 95% sensitivity and 90% specificity in control-group. The pooled sensitivity, specificity, positive and negative predictive values and accuracy were 90%, 60%, 69.2, 85.7 and 75% respectively.

CONCLUSION

Aberrant DNA methylation of multiple genes is associated with disease progression in HCV related cirrhosis. Moreover, early detection of promotor methylation of these may sever as good biomarker for early detection and therapeutic targets in high risk patients.

Hepatocellular Carcinoma: Past and Future of Molecular Target Therapy

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer related mortality worldwide. The incidence of HCC has been increasing annually. Viral infection, alcohol usage, and other causes of cirrhosis have been identified as major risk factors for HCC development. The underlying pathogenesis has not been as well defined. There have been multiple hypotheses to the specific mechanisms of hepatocarcinogenesis and they share the common theme of chronic inflammation, increase oxidative stress, and genomic alteration. Therapeutic options of HCC have been primarily local and/or regional including transplantation, resection, and radial frequency ablation, chemoembolization or radio-embolization. For unresectable or metastatic disease, the options are limited. Conventional chemotherapeutic options have been noted to have limited benefit. Sorafenib has been the one and only systemic therapy which has demonstrated modest overall survival benefit. This has led to more extensive research with focus on targeted therapy. Numerous pre-clinical and early phase clinical studies have been noted but failed to show efficacy in later phase clinical trials. In an effort to identify new potential therapeutic options, new understanding of underlying pathways to hepatocarcinogenesis should be one of the main focuses. This leads to development of more molecularly targeted agents to specific pathways, and immunotherapy. This article provides a review of major studies of molecular targeted agents which attempts to target these specific pathways in HCC.

[Vascularization of hepatoceliular carcinoma]

The paper gives the data available in the literature on vascularization of hepatocellular carcinoma (HCC). Sinusoidal capillarization and unpaired arteries are shown to play an important role in the development and progression of HCC. The density of microvessels detected by immunohistochemical techniques is a morphological indicator of the degree of angiogenic processes. Higher-grade HCC is followed by changes in its vascularization and concurrent with a progressive increase in the proportion of blood entering along the hepatic artery. The morphological indicators of microvessel density are recommended to use as addi- tional criteria for determining the prognosis of the disease, designing targeted anti-angiogenic drugs, and evaluating the efficiency of performed therapy.

Review of angiogenesis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a hypervascular tumor, and its vascularity is unique and greatly different from peripheral parenchyma of liver. Afferent and efferent vessels of HCC lesions come to differ as the lesion develops. The characteristic of the flow regulates the common style of metastasis. The portal tract of the HCC lesion is the first site of the intrahepatic metastasis, because cancer cells roll into the portal vein via efferent flow. On microscopic observation, HCC displays marked vascular abnormalities, arteriogenesis and capillarization. Arteriogenesis is defined as the growth of functional collateral arteries covered with smooth muscle cells from pre-existing arteries. Sinusoidal capillarization involves the transformation of fenestrated hepatic sinusoids into continuous capillaries. Several angiogenic factors have been reported, and some of them are studied as prognostic factors or target molecules of chemotherapeutic reagents. However, the mechanism of neovascularization during HCC development is still unclear. This review discusses the characteristics of angiogenesis in HCC and known angiogenic factors of HCC.

Immunohistochemical Study of Glypican-3 and HepPar-1 in Differentiating Hepatocellular Carcinoma from Metastatic Carcinomas in FNA of the Liver

Hepatocellular carcinoma (HCC) remains a common malignant cancer worldwide, it is considered the fifth most common malignant cancer. On the other hand, metastatic tumors are widespread in the liver , with metastatic adenocarcinoma (MA) constituting the greatest part, therefore differentiation of HCC from MA is a frequent problem facing the pathologist especially in liver fine-needle aspiration biopsies. Evaluating the diagnostic value of glypican-3 (GPC-3) and HepPar-1 immunostaining in differentiating hepatocellular carcinoma from metastatic tumors in liver cell block material. Fourty eight cell blocks prepared from FNA from the liver ( 30 cases HCC, 18 cases metastatic carcinoma in liver) stained by Glypican -3 and HepPar-1 immunohistochemical markers. Glypican-3 was immunoexpressed in 97% of cases of HCC while all cases of metastatic carcinoma were negative. HepPar-1 was expressed in 93% of cases of HCC and 11% of metastatic carcinoma of the liver. In this study the sensitivity of GPC3 in the diagnosis of HCC in cytological material was 96.7% and the specificity was 100% while the sensitivity and specificity of HepPar-1 was 93.3% and 88.9% respectively. Immunohistochemical staining for GPC-3 in cell block material of the liver is highly sensitive and specific and it is a valuable tool capable of differentiating HCC from most of metastatic tumors of the liver.

Prognostic implications of tumor vascularity and its relationship to cytokeratin 19 expression in patients with hepatocellular carcinoma

OBJECTIVE

Although hepatocellular carcinoma (HCC) demonstrates characteristic hypervascularity, some HCCs have a hypovascular pattern on computed tomography (CT). Cytokeratin 19 (CK19) is a marker for the biliary phenotype reflecting a poor prognosis. We assessed the prognostic implications of tumor vascularity and its association with CK19 expression in HCC.

METHODS

Patients that underwent surgical resection for HCC were included. Tumor vascularity was evaluated according to the arterial enhancement patterns on CT scans and CK19 expression was evaluated by using tissue microarray methods.

RESULTS

One hundred and forty patients were included. Their median follow-up duration was 55.0 months, and 92 (65.7%) patients had tumor recurrence. Forty-five patients (30.6%) had hypovascular HCC at the time of diagnosis, and they showed a significantly higher CK19 expression rate (32.5% vs. 8.2%, P = 0.001) and earlier recurrence rate within 6 months (hazard ratio (HR), 2.301; P = 0.025) compared to the patients with hypervascular HCCs. Hypovascularity (HR, 1.694; P = 0.045) was an independent risk factor for short overall survival.

CONCLUSIONS

Hypovascular HCCs were associated with early recurrence and short overall survival, and CK19 was more frequently expressed in hypovascular HCC than in hypervascular tumors. Therefore, tumor vascularity on CT images might be utilized in determining the prognosis of patients with HCCs.

Recent Advances in CT and MR Imaging for Evaluation of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. Accurate diagnosis and assessment of disease extent are crucial for proper management of patients with HCC. Imaging plays a crucial role in early detection, accurate staging, and the planning of management strategies. A variety of imaging modalities are currently used in evaluating patients with suspected HCC; these include ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), nuclear medicine, and angiography. Among these modalities, dynamic MRI and CT are regarded as the best imaging techniques available for the noninvasive diagnosis of HCC. Recent improvements in CT and MRI technology have made noninvasive and reliable diagnostic assessment of hepatocellular nodules possible in the cirrhotic liver, and biopsy is frequently not required prior to treatment. Until now, the major challenge for radiologists in imaging cirrhosis has been the characterization of small cirrhotic nodules smaller than 2 cm in diameter. Further technological advancement will undoubtedly have a major impact on liver tumor imaging. The increased speed of data acquisition in CT and MRI has allowed improvements in both spatial and temporal resolution, which have made possible a more precise evaluation of the hemodynamics of liver nodules. Furthermore, the development of new, tissue-specific contrast agents such as gadoxetic acid has improved HCC detection on MRI. In this review, we discuss the role of CT and MRI in the diagnosis and staging of HCC, recent technological advances, and the strengths and limitations of these imaging modalities.

[Latest developments in ultrasound of the liver]

Abdominal ultrasound (US) is often the first-line imaging modality used to assess focal liver lesions. Due to various new gray-scaled US techniques, such as tissue harmonic imaging (THI), spatial compounding technique and speckle reduction technique, as well as contrast-enhanced techniques, abdominal ultrasound nowadays has great potential regarding detection and characterization of focal liver lesions. Furthermore, image fusion with computed tomography (CT), magnetic resonance imaging (MRI) and 3D ultrasound will most likely help to improve clinical management before and after interventional procedures. This article illustrates the principles and clinical impact of recently developed techniques in the field of ultrasound.

Identification of a secretory protein c19orf10 activated in hepatocellular carcinoma

The identification of genes involved in tumor growth is crucial for the development of inventive anticancer treatments. Here, we have cloned a 17-kDa secretory protein encoded by c19orf10 from hepatocellular carcinoma (HCC) serial analysis of gene expression libraries. Gene expression analysis indicated that c19orf10 was overexpressed in approximately two-thirds of HCC tissues compared to the adjacent noncancerous liver tissues, and its expression was significantly positively correlated with that of alpha-fetoprotein (AFP). Overexpression of c19orf10 enhanced cell proliferation of AFP-negative HLE cells, whereas knockdown of c19orf10 inhibited cell proliferation of AFP-positive Hep3B and HuH7 cells along with G1 cell cycle arrest. Supplementation of recombinant c19orf10 protein in culture media enhanced cell proliferation in HLE cells, and this effect was abolished by the addition of antibodies developed against c19orf10. Intriguingly, c19orf10 could regulate cell proliferation through the activation of Akt/mitogen-activated protein kinase pathways. Taken together, these data suggest that c19orf10 might be one of the growth factors and potential molecular targets activated in HCC.

Liver transplantation for hepatocellular carcinoma without preoperative tumor biopsy

BACKGROUND

Progress in liver imaging has made pretransplantation tumor biopsy no longer systematic in patients with hepatocellular carcinoma (HCC).

OBJECTIVES

Our aim was to evaluate the accuracy of a preoperative diagnosis of HCC based on clinical and radiological findings in 102 cirrhotics qualified for liver transplantation (LT) between January 1995 and August 2003 at our institution.

METHODS

The diagnostic accuracy of our policy was assessed by comparing pretransplant diagnosis with the pathologic report of explanted livers.

RESULTS

Sensitivity, specificity, positive, and negative predictive values for the preoperative clinical and radiological diagnosis of HCC were 89%, 94.3%, 77%, and 93.3%, respectively. A false-positive preoperative diagnosis was made in 20 of 102 patients (19.6%) (dysplastic nodules [n=9], regenerative nodules [n=5] cholangiocellular carcinoma [n=1], hemangioma [n=1], and no lesion [n=4]). All tumors larger than 3 cm were correctly diagnosed, irrespective of serum alpha-fetoprotein (sAFP) levels. The risk of overestimating the diagnosis of HCC in the subgroup of patients with tumors less than 3 cm was conversely correlated with preliver transplantation sAFP (sAFP<or=100 ng/L: 28%; sAFP>100: 11%; sAFP>200: 0%).

CONCLUSION

In cirrhotics with nodules larger than 3 cm irrespective of sAFP or nodules less than 3 cm with sAFP greater than 200 ng/L, the pretransplant diagnosis of HCC can be made without performing biopsy. In other cases (i.e., nodules less than 3 cm and sAFP lower than 200 ng/L), histologic confirmation of HCC or a close follow-up imaging should be considered.

Diffusion-weighted MR: therapeutic evaluation after chemoembolization of VX-2 carcinoma implanted in rabbit liver

RATIONALE AND OBJECTIVES

The study goal was to evaluate the ability of diffusion-weighted imaging (DWI) in assessing the viability of rabbit liver VX-2 tumor after transcatheter arterial chemoembolization (TACE).

MATERIALS AND METHODS

VX-2 tumors were grown in the livers of 19 rabbits, and chemoembolization was performed. MR imaging was acquired 1 week after TACE. The rabbits were killed for histologic investigation immediately after MR imaging, and the proportion of viable tumor was calculated based on histopathologic examination. Apparent diffusion coefficient (ADC) values were measured in viable and necrotic tumor portion, and were compared using the paired Student's t test.

RESULTS

Viable tumors were absent (n = 3), less than 5% (n = 6), and 5% or more (n = 10) at pathology examination. On DWI, three tumors with no viable portion were interpreted as having no viable portion, but three of six tumors with a viable portion of less than 5% were considered as having no viable portion. The mean ADC values of necrotic and viable tumor were 1.653 +/- 0.126 mm(2)/sec and 0.883 +/- 0.407 mm(2)/sec (b = 1000 sec/mm(2)), respectively, and the ADC values of necrotic tumors were significantly greater than those in viable tumors (p < .01).

CONCLUSION

Although DWI is a useful tool for assessing tumor viability, viable tumor may not be detected on DWI when it is too small.

Magnetic resonance imaging of liver malignancies

The histological structure of the liver is complex, consisting of hepatocytes, biliary epithelium, and mesenchymal cells. From this large variety of cells, a broad spectrum of benign and malignant liver lesions in originate. An accurate diagnosis of these lesions is mandatory for choosing an appropriate therapeutic approach. With the recent developments in hardware and software, magnetic resonance imaging (MRI) has emerged as the method of choice in the diagnostic workup of focal liver lesions, in particular in the pretherapeutic stage. The introduction of high-field MRI at 3.0 T in the routine workup and the selective use of liver-specific contrast agents, including hepatobiliary and reticuloendothelial agents, have also strengthened the role of MRI in liver imaging. In this overview article, we will review the recent developments in 3.0-T MRI and MRI contrast agents in the diagnostic workup of the most common malignant liver tumors.

[Imaging nodules within cirrhotic liver: how do I do it?]

Cirrhosis is a chronic liver disease characterized by the presence of diffuse parenchymal necrosis, reactive fibrosis and nodular regeneration. These regenerative nodules may evolve into dysplastic nodules and finally nodules of hepatocellular carcinoma (HCC). Improved survival of cirrhotic patients with HCC depends on eligibility to liver transplantation. The purpose of this paper is to review the imaging features of liver nodules within cirrhotic liver and to propose the imaging strategies when considering the possibility of liver transplantation.

The role of contrast-enhanced ultrasound for focal liver lesion detection: an overview

The development of new ultrasound (US) contrast agents and sonographic techniques has considerably improved the possibilities of ultrasound in the assessment of liver tumors. An overview is given on diagnostic potential of contrast-enhanced US (CEUS) and real-time low mechanical index technique in the detection of various focal liver lesions compared with computed tomography, magnetic resonance imaging or intraoperative US. In two of our own studies that included 100 patients each we showed an increase of correct findings in CEUS compared with B-mode US from 64% to 87% and from 67% to 84% as confirmed by intraoperative evaluation of the liver. Especially after chemotherapy and in the case of small metastases, significantly more metastases were correctly detected by CEUS compared with B-mode US. These results and clinical study results in the literature show that CEUS allows tumor detection and direct visualization of the tumor vascularity and put contrast-enhanced sonography among recommended noninvasive imaging methods for focal liver lesions with improvements in diagnostic strategy.

Doppler and harmonic ultrasound for hepatocellular carcinoma

Ultrasound (US) is the imaging method most frequently used for the detection and diagnosis of hepatocellular carcinoma (HCC). US image quality has greatly improved in recent years, with advances in transducer, beam-former technology and sophisticated image processing. In addition, the recent availability of US contrast agents including first- and second-generation contrast agents and the remarkable advances in US technology have led to the rapid development of new imaging methods such as low and high mechanical index (MI) imaging technology for the vascular phase and parenchymal phase of the liver. In terms of contrast agent, most reported studies in Asian countries have used a very fragile, first-generation microbubble agent. Nowadays, more stable,second-generation contrast agents are developing and used in clinical application to the liver. In the future, better results can be obtained in the diagnosis of HCC, decision of treatment method and assessment of therapeutic response if more durable contrast agents are used with advanced US techniques. In this article, the principles, methods, imaging findings and potential roles of new diagnostic US techniques with contrast agents in the diagnosis of HCC are discussed.

Enhancement pattern of hepatocellular carcinoma: comparison of real-time contrast-enhanced ultrasound and contrast-enhanced computed tomography

We compared the enhancement pattern of 98 hepatocellular carcinoma nodules in 92 patients on contrast-enhanced ultrasound (CEUS) and contrast-enhanced computed tomography (CECT). Contrast-enhanced ultrasound was performed with SonoVue and a low mechanical index method. In arterial phase, 98 nodules were hyperenhancing on CEUS and 94 on CECT. In portal phase, 82 nodules were hypoenhancing on CEUS and 83 on CECT. Peripheral thin-rim-like enhancement was exhibited in 30 nodules on CEUS and 31 on CECT. Intratumoral vessels were visualized in 94 nodules on CEUS and 36 on CECT.

Gene expression profile related to the progression of preneoplastic nodules toward hepatocellular carcinoma in rats

In this study, we investigated the time course gene expression profile of preneoplastic nodules and hepatocellular carcinomas (HCC) to define the genes implicated in cancer progression in a resistant hepatocyte model. Tissues that included early nodules (1 month, ENT-1), persistent nodules (5 months, ENT-5), dissected HCC (12 months), and normal livers (NL) from adult rats were analyzed by cDNA arrays including 1185 rat genes. Differential genes were derived in each type of sample (n = 3) by statistical analysis. The relationship between samples was described in a Venn diagram for 290 genes. From these, 72 genes were shared between tissues with nodules and HCC. In addition, 35 genes with statistical significance only in HCC and with extreme ratios were identified. Differential expression of 11 genes was confirmed by comparative reverse transcription-polymerase chain reaction, whereas that of 2 genes was confirmed by immunohistochemistry. Members involved in cytochrome P450 and second-phase metabolism were downregulated, whereas genes involved in glutathione metabolism were upregulated, implicating a possible role of glutathione and oxidative regulation. We provide a gene expression profile related to the progression of nodules into HCC, which contributes to the understanding of liver cancer development and offers the prospect for chemoprevention strategies or early treatment of HCC.

Hepatocellular carcinoma in patients with chronic liver disease: comparison of SPIO-enhanced MR imaging and 16-detector row CT

PURPOSE

To compare the sensitivity, positive predictive value, and diagnostic accuracy of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging with those of 16-detector row computed tomography (CT) for the detection of hepatocellular carcinoma (HCC) in patients with hepatitis B-induced cirrhosis.

MATERIALS AND METHODS

Institutional Review Board approval was obtained for this study, and informed consent was obtained from all patients. A total of 44 patients (36 men, eight women; age range, 35-67 years) with 59 HCCs and mild liver cirrhosis (Child-Pugh score A or B) underwent multiphasic CT and SPIO-enhanced MR imaging. The diagnosis of HCC was established at surgical resection (n = 31) and percutaneous biopsy (n = 28). SPIO-enhanced MR imaging was composed of T2-weighted turbo spin-echo and T2*-weighted gradient-echo sequences. Multiphasic CT consisted of four phases (ie, early arterial, late arterial, portal venous, and equilibrium). Three observers independently analyzed each image in random order. Sensitivity, positive predictive value, and diagnostic accuracy were calculated by using the alternative free-response receiver operating characteristic analysis for multi-detector row CT and SPIO-enhanced MR imaging.

RESULTS

Although not significant (P > .05), the area under the receiver operating characteristic curve for SPIO-enhanced MR imaging (mean, 0.90) was higher than that for multi-detector row CT (mean, 0.82) for all observers. Also, although no significant difference was demonstrated by any of the three observers (P > .05), there was a trend toward increased sensitivity on both a per-lesion and a per-patient basis for SPIO-enhanced MR imaging (mean, 84.7% and 94.7%, respectively) compared with multi-detector row CT (mean, 76.9% and 88.6%, respectively). No significant difference in positive predictive value was observed between modalities.

CONCLUSION

SPIO-enhanced MR imaging and multiphasic CT show similar diagnostic accuracy, sensitivity, and positive predictive value for the detection of HCC in patients with relatively mild hepatitis B-induced cirrhosis.

Trial of a quantitative method for evaluating hemangioma of the liver and hepatocellular carcinoma using a radio-frequency signal

PURPOSE

In recent years, advances in ultrasonographic techniques have allowed the detection of even small hepatocellular carcinomas. However, many cases do not show distinctive ultrasonographic features. A quantitative ultrasonographic procedure for making the diagnosis would therefore be desirable. It is recognized that radio-frequency (RF) signals from hepatic tumors conform to the K distribution. The K distribution is used for the characterization of the statistical properties of backscattering signals from heterogeneous regions. In this study, RF signals were acquired from hemangioma of the liver (hemangioma) and hepatocellular carcinoma (HCC), and parameters of the K distribution, i.e., φ (the mean square of the amplitude of RF signals) and α (the number of effective scatterers), were calculated for the quantitative ultrasonographic evaluation of hepatic tumors.

METHODS

This study included 10 nodules of 10 patients with hemangioma and 27 nodules of 24 patients with HCC. The A-mode RF signals passing through the hepatic tumors were acquired with an Aloka SSD-1000 ultrasound system, and measurement units comprising 279 points were set on the RF signals corresponding to the tumor lesion. The parameters of the K distribution that were most consistent with the histogram were calculated and assessed.

RESULTS

With regard to φ, the values were high in hemangioma, and there was a significant (P < 0.05) difference in the φ value between hemangioma and HCC. On the other hand, there was no significant difference in the α value between hemangioma and HCC.

CONCLUSION

The α values of hemangioma were equivalent to those of HCC, while the φ values for hemangioma were higher than those for HCC. It was deduced from these observations that a situation in which an electron beam is likely to scatter exists in the tumor. This is also consistent with the pathological findings reported from previous studies. The use of these parameters is expected to allow quantitative ultrasonographic evaluation of hepatic tumors.

MR diffusion-weighed imaging of rabbit liver

AIM: To study the techniques of MR diffusion-weighed imaging (DWI) for normal rabbit liver.

METHODS: After 15 normal New Zealand white rabbits and one New Zealand white rabbit implanted with VX-2 tumor were anesthetized with 3% soluble pentobarbitone, DWI was performed respectively for different b values, repetition times (TR) or thicknesses, when other parameters were the same and magnetic resonance imaging (MRI) was performed respectively, or with different field of views (FOV) or coil when other parameters were the same. The distinction between groups was analyzed by SPSS10.0 with apparent diffusion coefficient (ADC), quality index (QI) or signal-noise ratio (SNR).

RESULTS: As b value increased, liver ADC, QI and SNR of DWI became smaller and simultaneously (F = 292.87, 156.1, 88.23, P<0.01). QI of DWI was high, when b value was 10, 50 or 100 respectively, but the distinction between them was insignificant; when b value was 800, QI and SNR of DWI were low. QI and SNR of DWI had no significant difference between TR = 4 000, 6 000 and 8 000. QI of DWI with 2 mm thickness was bigger than that with 5 mm thickness (t = 3.04, P<0.01), but SNR of DWI with 2 mm thickness was significantly smaller (t = -17.86, P<0.01). SNR of MRI with knee joint coil was obviously bigger than that with cranium coil [t = -5.77 (T1WI) or -4.02 (T2WI), P<0.01], but QI of MRI was smaller on the contrary [t = 7.10 (T1WI) or 3.97 (T2WI), P<0.01]. When FOV was enlarged gradually, SNR of MRI increased [F = 85.81 (T1WI) or 221.96 (T2WI), P<0.01], but QI firstly increased, then decreased [F = 68.67 (T1WI) or 69.46 (T2WI), P<0.01] and QI of MRI was the biggest when FOV was 20 cm×15 cm.

CONCLUSION: The scanning technique is very important in DWI of rabbit liver and the overall quality of DWI with b (100 s/mm2), thickness (2 mm), cranium coils and FOV (20 cm×15 cm) was best in our study, when other parameters were the same.

Approaches to the diagnosis of hepatocellular carcinoma

The advent of screening programs for hepatocellular carcinoma in patients with chronic viral hepatitis and cirrhosis has resulted in detection of smaller and smaller lesions in the liver. Some of these are small carcinomas, but many are not malignant in nature or are potential precursors to malignancy. Neither radiology nor biopsy can be used confidently to distinguish between these possibilities when the lesions are smaller than approximately 1.5 cm in diameter. Therefore, diagnostic algorithms must be developed to assist physicians in investigating these small lesions and deciding when they are truly malignant, when treatment is necessary, or whether a watchful waiting course is appropriate. The diagnostic difficulties are presented, with examples of diagnostic algorithms that may be helpful in managing these patients.

Diagnosis of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is responsible for a large proportion of cancer deaths worldwide. HCC is frequently diagnosed after the development of clinical deterioration at which time survival is measured in months. Long-term survival requires detection of small tumors, often present in asymptomatic individuals, which may be more amenable to invasive therapeutic options. Surveillance of high-risk individuals for HCC is commonly performed using the serum marker alpha-fetoprotein (AFP) often in combination with ultrasonography. Various other serologic markers are currently being tested to help improve surveillance accuracy. Diagnosis of HCC often requires more sophisticated imaging modalities such as CT scan and MRI, which have multiphasic contrast enhancement capabilities. Serum AFP used alone can be helpful if levels are markedly elevated, which occurs in fewer than half of cases at time of diagnosis. Confirmation by liver biopsy can be performed under circumstances when the diagnosis of HCC remains unclear.