Dysplastic nodules in liver cirrhosis: evaluation of hemodynamics with CT during arterial portography and CT hepatic arteriography

Current Concepts of Precancerous Lesions of Hepatocellular Carcinoma: Recent Progress in Diagnosis

The most common cause of hepatocellular carcinoma (HCC) is chronic hepatitis and cirrhosis. It is proposed that precancerous lesions of HCC include all stages of the disease, from dysplastic foci (DF), and dysplastic nodule (DN), to early HCC (eHCC) and progressed HCC (pHCC), which is a complex multi-step process. Accurately identifying precancerous hepatocellular lesions can significantly impact the early detection and treatment of HCC. The changes in high-grade dysplastic nodules (HGDN) were similar to those seen in HCC, and the risk of malignant transformation significantly increased. Nevertheless, it is challenging to diagnose precancerous lesions of HCC. We integrated the literature and combined imaging, pathology, laboratory, and other relevant examinations to improve the accuracy of the diagnosis of precancerous lesions.

Liver disease severity predicts carcinogenesis of dysplastic liver nodules in cirrhosis

While dysplastic liver nodules in cirrhosis are pre-malignant, little is known about the predictors of hepatocarcinogenesis of these lesions. This was a retrospective observational study of subjects with cirrhosis who had at least one hypervascular, non-malignant intrahepatic nodule on imaging while undergoing outpatient management by a tertiary hepatology referral centre between Jan 2009 and Jan 2019. Clinical and biochemical parameters were collected. The primary endpoint was transformation to hepatocellular carcinoma (HCC) as determined by Liver Imaging Reporting and Data System. During the study period, 163 non-malignant hypervascular nodules were identified in 77 patients; 147 had at least 6 months of follow up imaging and 16 received upfront radiofrequency ablation upon detection. During a median follow up of 38.5 months (IQR 16.5-74.5), 25 (17%) of the 147 hypervascular nodules being monitored transformed to HCC. On multivariate analysis, Child-Pugh grade was found to be the only independent predictor of nodule transformation into HCC (p = 0.02). Those with Child-Pugh B and C liver disease had a 10.1 (95% CI 1.22-83.8; p = 0.03) and 32.6-fold (95% CI 2.3-467; p = 0.01) increased risk respectively for HCC transformation compared to Child-Pugh A subjects. This large, single centre study demonstrates that around 20% of dysplastic nodules in cirrhotic patients undergo hepatocarcinogenesis during follow up, and that Child Pugh grade is the only independent predictor of transformation to HCC. Additional prospective studies are warranted to better understand the risk profile of these nodules, and how best they should be managed.

Role of liver biopsy in hepatocellular carcinoma

The role of liver biopsy in the diagnosis of hepatocellular carcinoma (HCC) has been challenged over time by the ability of imaging techniques to characterize liver lesions in patients with known cirrhosis. In fact, in the diagnostic algorithm for this tumor, histology is currently relegated to controversial cases. Furthermore, the risk of complications, such as tumor seeding and bleeding, as well as inadequate sampling have further limited the use of liver biopsy for HCC management. However, there is growing evidence of prognostic and therapeutic information available from microscopic and molecular analysis of HCC and, as the information content of the tissue sample increases, the advantages of liver biopsy might modify the current risk/benefit ratio. We herein review the role and potentiality of liver biopsy in the diagnosis and management of HCC. As the potentiality of precision medicine comes to the management of HCC, it will be crucial to have rapid pathways to define prognosis, and even treatment, by identifying the patients who could most benefit from target-driven therapies. All of the above reasons suggest that the current role of liver biopsy in the management of HCC needs substantial reconsideration.

Differentiating malignant from benign hyperintense nodules on unenhanced T1-weighted images in patients with chronic liver disease: using gadoxetic acid-enhanced and diffusion-weighted MR imaging

PURPOSE

To evaluate value of gadoxetic acid-enhanced and diffusion-weighted (DW) MRI for distinguishing malignant from benign hyperintense nodules on unenhanced T1-weighted images (T1WIs) in patients with chronic liver disease.

MATERIALS AND METHODS

Forty-two patients with 37 malignant and 41 benign hyperintense nodules on unenhanced T1WIs who underwent gadoxetic acid-enhanced and DW MRI, followed by histopathological examination, were included. Qualitative and quantitative analyses were conducted. Significant findings on univariate and multivariate analyses were identified and their diagnostic performances were analyzed for predicting hyperintense hepatocellular carcinomas (HCCs).

RESULTS

In univariate analysis, hyperintensity on T2WI, arterial enhancement, washout, hypointensity on hepatobiliary phase, and diffusion restriction were more frequently observed (P < 0.05) in hyperintense HCCs. Tumor-to-liver SI ratio on hepatobiliary phase and minimum apparent diffusion coefficient (ADC_min) were significantly lower in hyperintense HCCs (P < 0.05). In multivariate analysis, hyperintensity on T2WI (OR, 13.58; P = 0.02), arterial enhancement (OR, 8.21; P = 0.002), and ADC_min ≤ 0.83 × 10^-3 mm²/s (OR, 6.88; P = 0.008) were independently significant factors for predicting hyperintense HCCs. When two of three criteria were combined, 75.7% (28/37) of hyperintense HCCs were identified with a specificity of 92.7%, and when all three criteria were satisfied, the specificity was 97.6%.

CONCLUSION

Gadoxetic acid-enhanced and DW MRI may be helpful for differentiating malignant from benign hyperintense nodules on unenhanced T1WI.

Integration of Contrast-enhanced US into a Multimodality Approach to Imaging of Nodules in a Cirrhotic Liver: How I Do It

Accurate characterization of cirrhotic nodules and early diagnosis of hepatocellular carcinoma (HCC) are of vital importance. Currently, computed tomography (CT) and magnetic resonance (MR) imaging are standard modalities for the investigation of new nodules found at surveillance ultrasonography (US). This article describes the successful integration of contrast material-enhanced US into a multimodality approach for diagnosis of HCC and its benefits in this population. The application of contrast-enhanced US immediately following surveillance US allows for prompt dynamic contrast-enhanced evaluation, removing the need for further imaging of benign lesions. Contrast-enhanced US also provides dynamic real-time assessment of tumor vascularity so that contrast enhancement can be identified regardless of its timing or duration, allowing for detection of arterial hypervascularity and portal venous washout. The purely intravascular nature of US contrast agents is valuable as the rapid washout of nonhepatocyte malignancies is highly contributory to their differentiation from HCC. The authors believe contrast-enhanced US provides complementary information to CT and MR imaging in the characterization of nodules in high-risk patients. ^© RSNA, 2017 Online supplemental material is available for this article.

Diffusion-weighted images (DWI) without ADC values in assessment of small focal nodules in cirrhotic liver

OBJECTIVE

To assess if diffusion-weighted magnetic resonance (MR) imaging without apparent diffusion coefficient (ADC) values provides added diagnostic value in combination with conventional MR imaging in the detection and characterization of small nodules in cirrhotic liver.

METHODS

Two observers retrospectively and independently analyzed 86 nodules (≤3 cm) certified pathologically in 33 patients with liver cirrhosis, including 48 hepatocellular carcinoma (HCC) nodules, 13 high-grade dysplastic nodules (HDN), 10 low-grade dysplastic nodules (LDNs) and 15 other benign nodules. All these focal nodules were evaluated with conventional MR images (T1-weighted, T2-weighted and dynamic gadolinium-enhanced images) and breath-hold diffusion-weighted images (DWI) (b=500 s/mm(2)). The nodules were classified by using a scale of 1-3 (1, not seen; 3, well seen) on DWI for qualitative assessment. These small nodules were characterized by two radiologists. ADC values weren't measured. The diagnostic performance of the combined DWI-conventional images and the conventional images alone was evaluated using receiver operating characteristic (ROC) curves. The area under the curves (Az), sensitivity and specificity values for characterizing different small nodules were also calculated.

RESULTS

Among 48 HCC nodules, 33 (68.8%) were graded as 3 (well seen), 6 (12.5%) were graded as 2 (partially obscured), and 9 weren't seen on DWI. Among 13 HDNs, there were 3 (23.1%) and 4 (30.8%) graded as 3 and 2 respectively. Five (50%) of 10 benign nodules were partially obscured and slightly hyperintense. For 86 nodules, the average diagnostic accuracy of combined DWI-conventional images was 82.56%, which was increased significantly compared with conventional MR images with 76.17%. For HCC and HDN, the diagnostic accuracy of combined DWI-conventional images increased from 78.69% to 86.07%.

CONCLUSIONS

Diffusion-weighted MR imaging does provide added diagnostic value in the detection and characterization of HDN and HCC, and it may not be helpful for LDN and regenerative nodule (RN) in cirrhotic liver.

Tumor Hemodynamics and Hepatocarcinogenesis: Radio-Pathological Correlations and Outcomes of Carcinogenic Hepatocyte Nodules

Tumor hemodynamics of carcinogenic hepatocytes nodules, that is, low grade dysplastic nodules, high grade dysplastic nodules, early hepatocellular carcinomas (HCCs), and progressed HCCs, change during multistep dedifferentiation of the nodules. Morphometric analyses of inflow vessels of these nodules indicate that the portal veins of carcinogenic hepatocyte nodules monotonically decrease whereas the arteries bitonically change, first decrease and then increase. Findings on imaging techniques depicting these changes in tumor blood inflows, especially intra-arterial contrast-enhanced computed tomography, closely related not only to the histological differentiation of the nodules but also to the outcomes of the nodules. Histological analyses of connections between the vessels within the tumors and those in the surrounding livers and findings on imaging techniques indicate that drainage vessels of HCC change from hepatic veins to hepatic sinusoids and then to portal veins during multistep hepatocarcinogenesis. Understanding of tumor hemodynamics through radio-pathological correlations will be helpful in drawing up therapeutic strategies for carcinogenic hepatocyte nodules arising in cirrhosis.

Contrast-enhanced magnetic resonance imaging of 102 nodules in cirrhosis: correlation with histological findings on explanted livers

PURPOSE

To analyze Gd-EOB-DTPA-enhanced magnetic resonance (MR) findings of nodules (low-grade dysplastic nodules-LGDNs; high-grade dysplastic nodules-HGDN, and hepatocellular carcinoma-HCC), histologically identified on cirrhotic, explanted livers.

METHODS

IRB approval was obtained for this study. Thirty-four patients underwent Gd-EOB-DTPA-enhanced MR examinations (1.5T system), that included 20-min delayed hepatobiliary (HB) phase imaging, before undergoing orthotopic liver transplantation (OLT; mean time MR-OLT: 2.7 months). A total of 102 hepatic nodules were identified and analyzed at histopathological examination, and classified as LGDN, HGDN, and HCC. Two radiologists by consensus performed a quantitative (enhancement ratios, ERs) and a qualitative analyses of signal intensities of identified nodules on vascular dynamic phases (30-35 s after injection-arterial phase; 180-190 s after injection late phase) and on HB phases. Correlation between nodules MR patterns and histological classification was analyzed by means of dedicated statistical software.

RESULTS

No differences were appreciable among ERs of HGDN and HCCs on HB phase (P > 0.001). Lesions' enhancement on vascular dynamic and on HB phases significantly correlated to histological classification of nodules (P < 0.0001). Nodular hyperintensity on arterial phase and hypointensity on late phase were highly predictive for HCC (PPV 100%), with a moderate sensitivity (72.5%). Nodular hypointensity on HB phase was detected on 39/40 HCCs (sensitivity 97.5%) and in 21/30 HGDNs, whereas no LGDN showed it.

CONCLUSIONS

Hyperenhancement on arterial phase and hypointensity on late phase are the most specific clues for the diagnosis of HCC. Hypointensity on HB phase shows a PPV of 100% in suggesting nodular premalignancy/malignancy, independently from nodular dynamic vascular enhancement.

Predictors of dysplastic nodule diagnosis in patients with liver cirrhosis on unenhanced and gadobenate dimeglumine-enhanced MRI with dynamic and hepatobiliary phase

OBJECTIVE

The purpose of this article is to assess whether unenhanced and gadobenate dimeglumine-enhanced MRI with dynamic and hepatobiliary phase may predict the diagnosis of dysplastic nodules in patients with liver cirrhosis.

MATERIALS AND METHODS

We retrospectively analyzed 75 cirrhotic patients (47 men and 28 women; mean [± SD] age, 55 ± 12 years) with 82 hepatocellular nodules, including histology-proven dysplastic nodules (n = 25; diameter, 1-3 cm) and hepatocellular carcinomas (n = 57; diameter, 2-3 cm) scanned by MRI before and after gadobenate dimeglumine injection during hepatic arterial phase (HAP), portal venous phase (PVP), equilibrium phase, and hepatobiliary phase. Nodule T1 and T2 intensities before contrast agent injection and nodule HAP, PVP, equilibrium phase, and hepatobiliary phase intensities were compared with the adjacent liver. Univariate and multivariate logistic regression analysis was conducted to assess how the nodule could predict dysplastic nodule diagnosis.

RESULTS

Some imaging findings were independent predictors of dysplastic nodule diagnosis-namely, nodule T2 isohypointensity (odds ratio [OR], 12.28; 95% CI, 3.88-38.82), T1 isohyperintensity (OR, 26.74; 95% CI, 7.53-94.90), HAP isohypointensity (OR, 97.16; 95% CI, 20.06-470.49), PVP-equilibrium phase isohyperintensity (OR, 20.53; 95% CI, 5.36-78.62), and hepatobiliary phase isohyperintensity (OR, 119.6; 95% CI, 21.59-662.40). Nodule T2 and HAP isohypointensity (OR 31.47; 95% CI, 7.88-125.58), nodule T2 isohypointensity and hepatobiliary phase isohyperintensity (OR, 28.77; 95% CI, 7.79-106.19), nodule T1 isohyperintensity and HAP isohypointensity (OR, 17.22; 95% CI, 4.85-61.14), and nodule T1 and hepatobiliary phase isohyperintensity (OR, 19.39; 95% CI, 5.38-69.90) were also predictors of dysplastic nodule diagnosis.

CONCLUSION

The combination of nodule appearance on T2-weighted MRI and nodule enhancement after gadobenate dimeglumine injection may predict dysplastic nodule diagnosis in patients with liver cirrhosis.

Hepatocarcinogenesis: imaging-pathologic correlation

Rapid advances in liver surgery, including liver transplantation, radiology, and pathology, have created a need for clinically relevant nomenclature for premalignant and early lesions of hepatocellular carcinoma (HCC). Precancerous lesions include dysplastic foci and dysplastic nodules (DNs) characterized by cytologic or structural atypia. Although imaging diagnosis is playing a crucial role in the evaluation of hepatocarcinogenesis and early diagnosis of HCC, it is still challenging to accurately characterize borderline nodules such as small arterially enhancing lesions or hypovascular nodules. This article discusses pathological and radiological features of these small nodular lesions and offers insights into the multistep process of hepatocarcinogenesis by describing the progression of pathologic change linking DNs to HCC.

Success of image-guided biopsy for small (≤ 3 cm) focal liver lesions in cirrhotic and noncirrhotic individuals

PURPOSE

Imaging techniques can detect small liver lesions, although these are a challenge to biopsy, particularly in cirrhotic liver. The authors assessed the diagnostic success of image-guided biopsies collected from small (≤ 3 cm) focal liver lesions.

MATERIALS AND METHODS

This single-center, retrospective study included 374 patients (199 men; mean age, 62 ± 15). Eighteen-gauge core biopsy and 22-gauge fine needle aspiration (FNA) samples were collected from small focal liver lesions. Samples were compared by histology versus cytology, malignant versus benign, from lesions smaller versus larger than 1.5 cm, from livers with versus without cirrhosis, collected by computed tomography (CT) guidance versus ultrasound, and from different locations in the liver.

RESULTS

The combined accuracy of core biopsy plus FNA analysis was 95.5%; core biopsy alone characterized 93.3% of samples, and FNA alone characterized 72.5% (P < .001). Biopsy successfully characterized 94.5% of malignant lesions and 98.8% of benign lesions (P > .05). Biopsy characterized 95.3% (102 of 107) lesions ≤ 1.5 cm. The success in cirrhotic livers was 94.8%, for CT-guided biopsies was 95%, and for ultrasound-guided biopsies was 95.8% (P > .05). The success rate was lower in liver caudate lobe than in other locations (P < .05).

CONCLUSIONS

Image-guided biopsy of small (≤ 3 cm) focal liver lesions is highly reliable with the use of core biopsy alone. Neither size ≤ 1.5 cm nor presence of cirrhosis is an impediment to biopsy. CT and ultrasound guidance produce similar rates of success.

Accuracy of hepatocellular carcinoma detection on multidetector CT in a transplant liver population with explant liver correlation

AIM

To evaluate the diagnostic accuracy of multidetector computed tomography (MDCT) for hepatocellular carcinoma (HCC) in cirrhotic patients undergoing liver transplantation. Secondary aims were to examine the effect of radiologist experience and lesion size on diagnostic accuracy.

MATERIALS AND METHODS

Thirty-nine patients (72% male with a mean age of 56.5 years) underwent liver transplantation following preoperative triple-phase MDCT examination of the liver. MDCT examinations were retrospectively independently reviewed by three radiologists for the presence and location of suspected HCCs, with the diagnostic confidence recorded using a five-point confidence scale. MDCT examinations were compared with explant specimens for histopathological correlation.

RESULTS

Histopathological results demonstrated 46 HCCs in 29 of the 39 patients. Analysis demonstrated a sensitivity of 65-75% and specificity of 47-88% for detection of HCC lesions. The sensitivity dropped to 48-57% for lesions of size ≤20mm. As the diagnostic confidence increased, there was a further decrease in the sensitivity (4-26%). The radiologist with the greatest number of years experience was found to have a significantly higher accuracy of detection of HCC lesions compared with the least experienced radiologist.

CONCLUSION

Larger lesion size of HCC and greater number of years experience of the radiologist resulted in significantly higher accuracy of HCC lesion detection. The overall sensitivity and specificity results for MDCT detection of HCC are comparable to previous helical CT imaging.

Assessment of the diagnostic accuracy of T2*-weighted MR imaging for identifying hepatocellular carcinoma with liver explant correlation

BACKGROUND

T2*-weighted MRI may represent a novel method for identifying hepatocellular carcinoma (HCC). The goal of this study was to assess the diagnostic accuracy of T2*-weighted MRI for HCC with liver explant correlation.

MATERIALS AND METHODS

A retrospective review identified 25 patients who had undergone liver transplantation with pre-operative T2*-weighted MRI. All patients had Child's-Pugh A (9), B (9), or C (7) liver disease with 13 transplanted for liver dysfunction and 12 for HCC. The T2*-weighted images were interpreted by 2 blinded, independent observers and the results compared with the explanted specimens. Sensitivity and specificity of T2*-weighted MRI for the identification of HCC was assessed.

RESULTS

By pathology, 16 HCC (mean largest diameter 2.1 cm; range 0.9-3.6 cm) were identified in 14 patients. Reader 1 had a sensitivity of 69% (95% confidence interval 41-88%) and a specificity of 100% (68-100%). Reader 2 had a sensitivity of 56% (31-79%) and a specificity of 100% (68-100%). There was a very good inter-observer agreement (kappa=0.84).

CONCLUSION

T2*-weighted MRI had a moderate sensitivity for identifying HCC but had an excellent specificity. A T2*-weighted MR sequence may be a useful component of a liver MRI protocol due to its high specificity for HCC, and may be particularly useful in patients unable to undergo gadolinium enhanced MRI.

Needle track seeding following percutaneous procedures for hepatocellular carcinoma

Neoplastic seeding may arise after diagnostic or therapeutic percutaneous procedures for hepatocellular carcinoma. The true incidence of seeding with hepatocellular carcinoma is difficult to assess precisely, but a significant risk of seeding exists and is greater when performing diagnostic biopsy as compared to therapeutic percutaneous procedures [radiofrequency ablation, radiofrequency ablation (RFA); percutaneous ethanol injection, Percutaneous ethanol injection (PEI)]. Whenever liver transplantation is feasible, diagnostic needle biopsies should be avoided, but RFA and PEI are often needed as "bridge" treatments. The role of adjuvant treatments in reducing the incidence of seeding following RFA or PEI requires further evaluation.

Hepatic perfusion imaging using factor analysis of contrast enhanced ultrasound

Contrast enhanced ultrasound imaging provides a real-time tool for evaluating vasculature in the liver. Primary liver cancer is known to be perfused exclusively by blood from the hepatic artery, whereas normal liver is also supplied by the portal vein. Visual separation of two different phases of enhancement from the independent feeding vessels is important for diagnosis but remains a challenge. This paper presents a method of using factor analysis for extracting distinct time-intensity curves. A key component to this extraction is the clustering of measured bolus curves and their projection onto a positivity domain to obtain nonnegative curves. This technique provides complementary images representing spatial loadings on each curve. As little as 1% of the data is required to contain unmixed signals to extract time-intensity curves that correlate well with true curves. A method of combining this information to display a regional hepatic perfusion image is proposed, and results are tested on a set of 10 patients. Region of interest analysis suggests it is possible to detect changes in the hepatic perfusion index of liver lesions relative to normal liver parenchyma using contrast ultrasound.

Hepatocellular carcinoma in liver transplantation candidates: detection with gadobenate dimeglumine-enhanced MRI

OBJECTIVE

The purpose of this study was to retrospectively evaluate the diagnostic performance of dynamic gadobenate dimeglumine-enhanced MRI with explant pathologic correlation in the detection of hepatocellular carcinoma (HCC) in patients undergoing liver transplantation.

MATERIALS AND METHODS

Forty-seven patients (28 men, 19 women; mean age, 49 years) underwent dynamic gadobenate dimeglumine-enhanced MRI within 3 months before primary liver transplantation. Dynamic imaging was performed before (unenhanced) and after (hepatic arterial, portal venous, equilibrium, and 1-hour delayed phases) IV bolus administration of gadobenate dimeglumine at 0.1 mmol/kg body weight. Retrospective image analysis to detect HCC nodules was performed independently by two abdominal radiologists who had no pathologic information. On a per-nodule basis, the sensitivity and positive predictive value were calculated for the two observers. Sensitivity and specificity in the diagnosis of HCC also were evaluated. Fisher's exact test was performed to determine whether there was a detection difference between HCC nodules 1 cm in diameter or larger and nodules smaller than 1 cm and to evaluate the differences in causes of false-positive MRI findings based on lesion size (>or= 1 cm vs < 1 cm).

RESULTS

Twenty-seven patients had 41 HCCs. In HCC detection, gadobenate dimeglumine-enhanced MRI had a sensitivity of 85% (35 of 41 HCCs) and a positive predictive value of 66% (35 of 53 readings) for observer 1 and a sensitivity of 80% (33 of 41 HCCs) and a positive predictive value of 65% (34 of 52 readings) for observer 2. For both observers, sensitivity in the detection of HCCs 1 cm in diameter and larger (91-94%) was significantly different (p < 0.05) from that in detection of HCCs smaller than 1 cm (29-43%). Nonneoplastic arterial hypervascular lesions more often caused false-positive diagnoses of lesions smaller than 1 cm in diameter (80-86%) on MR images than of those 1 cm in diameter and larger (0-25%). The difference was statistically significant (p < 0.05) for both observers. In diagnosis, gadobenate dimeglumine-enhanced MRI had a sensitivity of 87% (20 of 23 patients) and a specificity of 79% (19 of 24 patients) for both observers.

CONCLUSION

Dynamic gadobenate dimeglumine-enhanced MRI has a sensitivity of 80-85% and a positive predictive value of 65-66% in the detection of HCC. The technique, however, is of limited value for detecting and characterizing lesions smaller than 1 cm in diameter.

Perfusion-weighted MRI in evaluating the intranodular hemodynamic characteristics of dysplastic nodules and hepatocellular carcinomas in an experimental rat model

PURPOSE

To investigate the value of perfusion-weighted MRI in the evaluation of the intranodular hemodynamic characteristics of dysplastic nodules (DNs) and hepatocellular carcinomas (HCCs) in an experimental rat model.

MATERIALS AND METHODS

A total of 40 rats with chemically-induced DNs and HCCs were investigated. Single-slice gadolinium-enhanced perfusion-weighted MRI was performed to evaluate the nodules. Time to peak (Tp), maximal relative signal enhancement (REmax), and the initial slope of signal intensity (SI) vs. time curves of the nodules and cirrhotic liver were evaluated. Nodules precisely corresponding to MRI were examined histologically. Paired Student's t-tests were used to compare the difference between nodules and cirrhotic liver.

RESULTS

A total of 20 HCCs and 14 DNs were evaluated. HCCs showed a significantly higher REmax, shorter Tp, and higher slope than adjacent cirrhotic liver. The REmax and slope of DNs were significantly lower than adjacent cirrhotic liver parenchyma. Although the Tp of DNs was delayed two to three seconds compared to adjacent cirrhotic liver, there was no significant difference between them.

CONCLUSION

Perfusion-weighted MRI detected the intranodular hemodynamic characteristics of DNs and HCCs in an experimental rat model. DNs were hypovascular compared to cirrhotic liver, while HCCs were markedly hypervascular.

Diagnostic value of hepatocellular nodule vascularity after microbubble injection for characterizing malignancy in patients with cirrhosis

OBJECTIVE

The purpose of this study was to assess the diagnostic value of hepatocellular nodule vascularity after microbubble injection for characterization of malignancy in patients with cirrhosis of the liver.

MATERIALS AND METHODS

After sulfur hexafluoride-filled microbubble injection, the vascularity of 236 hepatocellular nodules (1-5 cm in diameter) in 215 patients with cirrhosis (151 men, 64 women; mean age, 62 +/- 11 [SD] years) was evaluated by consensus of three reference radiologists. The relation between nodule vascularity in the arterial (10-40 seconds from injection) and portal venous (45 seconds to microbubble disappearance) phases and dimension of malignancy was evaluated by multivariate U statistical analysis. Two blinded independent reviewers using reference criteria classified nodules as benign or malignant after review of unenhanced and contrast-enhanced sonograms.

RESULTS

The final diagnoses were 96 malignant (84 hepatocellular carcinoma, 12 tumors not hepatocellular carcinoma) and 140 benign nodules (57 regenerative and 13 dysplastic nodules, 70 other benign lesions). Nodule hypervascularity during the arterial phase and hypovascularity during the portal venous phase (odds ratio, 27.78) and nodule diameter greater than 2 cm combined with hypervascularity during the arterial phase and isovascularity or hypervascularity during the portal venous phase (odds ratio, 3.3) were related to the presence of malignancy. Contrast-enhanced sonography improved diagnostic accuracy (unenhanced sonography vs contrast-enhanced sonography, 32% vs 71% for reviewer 1 and 22% vs 66% for reviewer 2; p < 0.05, McNemar test) even though hypervascular nodules 2 cm or smaller (malignant, n = 2; benign, n = 40) that appeared isovascular or hypervascular during the portal venous phase were misclassified.

CONCLUSION

Assessment of hepatocellular nodule vascularity after microbubble injection allowed characterization of malignancy, but characterization was limited for hypervascular nodules 2 cm or less in diameter.

Role of MDCT in the diagnosis of hepatocellular carcinoma in patients with cirrhosis undergoing orthotopic liver transplantation

OBJECTIVE

The purpose of this study was to assess the diagnostic performance of MDCT in the detection of hepatocellular carcinoma in patients with cirrhosis undergoing orthotopic liver transplantation.

MATERIALS AND METHODS

Eighty-eight consecutively registered patients who underwent MDCT 6 months before liver transplantation were evaluated. The original reports were analyzed, and the CT images were retrospectively reevaluated independently by two radiologists who made the final interpretation in consensus. The imaging findings were correlated with histopathologic findings in the explanted livers on a patient-by-patient and a lesion-by-lesion basis.

RESULTS

Histopathologic examination revealed 139 hepatocellular carcinomas in 48 of the 88 patients. MDCT correctly depicted 89 of 139 hepatocellular carcinomas (sensitivity, 64%) at the original examination and 102 at reevaluation (sensitivity, 73.3%). Patient-by-patient analysis showed a specificity of 75% in the original reports and of 77.5% at reevaluation. A large number of false-positive nodules were found, most (59.2%) of them being smaller than 1 cm in diameter.

CONCLUSION

MDCT has reasonable sensitivity in the detection of hepatocellular carcinoma in patients with cirrhosis who undergo liver transplantation. Attention should be paid, however, to avoiding overestimation of the extent of disease.

[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.

Diagnostic imaging of hepatocellular carcinoma in patients with cirrhosis before liver transplantation

1. The lack of whole-liver explant correlation has led to an overestimation of the sensitivity of imaging tests for the diagnosis of HCC in the radiological literature. 2. Ultrasound is insensitive for the diagnosis of HCC in the cirrhotic liver and should not be used for the detection of focal liver lesions in this setting. 3. Although magnetic resonance (MR) imaging is more sensitive than multidetector 3-phase computed tomography (CT) for the diagnosis of regenerative and dysplastic nodules it is probably no better than CT for detection of HCC and has a lower false-positive rate. 4. Approximately 10-30% of nodules measuring <2 cm seen only on the hepatic arterial phase at CT or MR imaging represent small HCC and vigilant surveillance imaging is required as interval growth is the best indicator of malignancy.

Comparison of visual and quantitative analysis for characterization of insonated liver tumors after microbubble contrast injection

OBJECTIVE

The objective of our study was to compare diagnostic performance of visual and quantitative analysis for the characterization of liver tumors insonated at low transmit power after microbubble contrast agent injection.

SUBJECTS AND METHODS

This series comprised 166 liver tumors (1-5 cm in diameter) in 166 patients (99 men, 67 women; mean age +/- SD, 58 +/- 11 years) scanned at low transmit power (mechanical index: 0.1-0.14) after sulfur hexafluoride-filled microbubble injection. Digital cine clips recorded at the arterial phase (10-40 sec after contrast injection) and late phase (100-300 sec) were analyzed to characterize liver tumors as benign or malignant. Visual analysis was performed by three independent blinded reviewers who evaluated enhancement patterns at the arterial phase and subjective tumor conspicuity at the late phase. Quantitative analysis of videotape intensity (VI: gray-scale levels, 0-255) was performed to calculate objective tumor conspicuity at the late phase: (VI(tumor) - VI(liver)) / VI(liver).

RESULTS

Characteristic enhancement patterns were observed in malignant tumors (peripheral rimlike) and benign tumors (peripheral nodular or central and spoke-wheel-shaped). Malignant (n = 95) versus benign (n = 71) tumors differed for subjective (median value: -1 vs 1, respectively) and objective conspicuity at the late phase (-0.6 vs 0.15, respectively; p = 0.001, Mann-Whitney U test) due to persistent microbubble uptake in benign tumors. Diagnostic performance of visual (odds ratio: reviewer 1 = 4.28, reviewer 2 = 10.18, reviewer 3 = 9.56) and quantitative (odds ratio: 89.33) analyses differed significantly in the characterization of liver tumors (p = 0.01, chi-square test).

CONCLUSION

Quantitative analysis revealed higher diagnostic performance than visual analysis to characterize liver tumors insonated at low transmit power after microbubble contrast agent injection.

Treatment of small hepatocellular carcinoma: a comparison of techniques and long-term results

OBJECTIVE

The aim of this study was to compare the results over time of transcatheter arterial chemoembolization (TACE), percutaneous ethanol injection (PEI), laser thermal ablation (LTA) and combined therapy in the treatment of small hepatocellular carcinoma.

METHODS

Between 1998 and 2004, 131 cirrhosis patients (99 Child-Pugh class A, 32 Child-Pugh class B) with a small hepatocellular carcinoma were included in the study; 34 were treated with PEI, 46 with LTA, 18 with TACE and 33 with combined therapy.

RESULTS

No major complication occurred during any procedure. Computed tomography scan showed that complete necrosis was achieved in 81% of treated nodules (120 out of 148); as a whole, the disease relapsed in 42 (32.0%) patients (with a disease-free interval of 17.0+/-13.7 months). The cumulative survival rates were 81.9, 35.7 and 20.8% at 12, 36 and 60 months respectively. A univariate analysis of survival showed statistically significant differences in the comparison between Child-Pugh class A with respect to Child-Pugh class B (P<0.0001) and between nodules with a diameter of 20 mm or less as opposed to larger than 20 mm (P=0.001). Patients subjected to LTA showed a statistically significant longer survival than those treated with TACE and PEI.

CONCLUSIONS

LTA proves to be the most effective treatment, affording reduced invasiveness, a limited number of sessions, complete necrosis in almost all cases and better total survival in the treated patients.

Ultrasonographic portography with low mechanical index gray-scale imaging in hepatic VX2 tumor

To evaluate the characteristics of portal blood supply of hepatic tumors by ultrasonographic portography (USP), an in vivo model was studied using SonoVue, a second-generation ultrasound contrast agent (UCA) and low mechanical index (MI), gray-scale harmonic imaging. SonoVue (0.05 mL) was administrated through catheter placed into the main trunk of portal vein at laparotomy, followed by a 0.5 mL saline flush, in 12 rabbits with hepatic VX2 tumor, implanted by VX2 tumor tissue cubes of approximately 1 mm3 from carrier rabbit. Results showed that low MI gray-scale imaging delineated clearly the dynamic enhancement of tumors and liver parenchyma. Among 22 tumors, seven tumors were diffusely increased, with the intensity of enhancement weaker than that of the surrounding liver parenchyma. The UCA was washed out earlier from tumors than from surrounding liver parenchyma. Three tumors showed the branches of portal vein. Five tumors showed peripheral contrast enhancement and a central coarse unenhanced hypoechoic area. Seven tumors displayed no actual enhancement. All lesions (100% [22 of 22]) were depicted clearly in the whole duration of enhancement, especially in the early and late phase, regardless of enhancement pattern, and portal blood flow was manifested in 15 of 22 (68%) tumors, by USP. The enhancement pattern of the tumors corresponded to the pathologic findings. The results indicated that ultrasonographic portography, combined with low MI levels and second-generation UCA, is a sensitive and safe method to study portal blood supply for liver cancer. It may contribute to improvement of the detectability and diagnostic ability and assist the choice of a therapeutic strategy for treatment of liver cancer. However, applicability of the method to human may be problematic because of high invasiveness and great difficulty in administering contrast medium.

Dysplastic nodules frequently develop into hepatocellular carcinoma in patients with chronic viral hepatitis and cirrhosis

BACKGROUND

Advances in imaging technology have enhanced the detection of small nodular lesions during the course of chronic liver disease.

METHODS

Between 1995 and 2002, the authors examined 154 consecutive patients with small hepatic nodules without hepatocellular carcinoma (HCC) over a median duration of 2.8 years. The median size of these nodules was 14 mm (range, 7-40 mm). The initial histopathologic diagnosis included high-grade dysplastic nodule (HGDN) (n=13), low-grade dysplastic nodule (LGDN) (n=42), and regenerative nodule (RN) (n=99).

RESULTS

A total of 29 (18.8%) nodules developed into HCC during the observation period. Cumulative HCC development rates at the first, third, and fifth year were 46.2%, 61.5%, and 80.8% for HGDN; 2.6%, 30.2%, and 36.6% for LGDN; and 3.3%, 9.7%, and 12.4% for RN, respectively. The rate of HCC development was significantly higher in the HGDN group than for other types (P<0.001). Multivariate analysis disclosed that histopathologic diagnosis (P<0.001) and findings on computed tomographic arterial portography (CT-AP) (P=0.004) were significantly associated with future HCC development. The hazard ratios of HGDN and LGDN were 16.8 (95% confidence interval [CI], 6.19-45.6) and 2.96 (95% CI, 1.20-7.31), respectively. A decrease in portal blood flow also showed a significantly high hazard ratio of 3.04 (95% CI, 1.42-6.50). Approximate annual development rate to HCC was 20% in patients with HGDN and 10% in LGDN.

CONCLUSION

HGDN should be considered a precancerous lesion when it appears during follow-up of chronic viral hepatitis or cirrhosis. Reduced portal blood flow in the nodule on computed tomography-AP is also an important predictor for development of hepatocellular carcinoma.

Importance of small (< or = 20-mm) enhancing lesions seen only during the hepatic arterial phase at MR imaging of the cirrhotic liver: evaluation and comparison with whole explanted liver

PURPOSE

To retrospectively assess the importance and imaging appearance of small (< or = 20 mm in diameter) hepatic arterial phase-enhancing (HAPE) lesions that are occult during portal and/or equilibrium phases and at unenhanced T1- and T2-weighted magnetic resonance (MR) imaging and to determine the gross pathologic diagnosis with whole-liver explant comparison.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board and compliant with HIPPA. Forty-six patients with cirrhosis who underwent MR imaging and transplantation within 90 days were evaluated with breath-hold T2-weighted and volumetric three-dimensional gadolinium-enhanced gradient-echo MR imaging in the hepatic arterial, portal venous, and equilibrium phases at 1.5 T. Three readers, who were blinded to the pathologic results, retrospectively reviewed the MR images in consensus for small HAPE nodules that were occult at T2-weighted and portal and/or equilibrium phase MR imaging. Only patients with nodules that enhanced during the arterial phase were included in the final study group, which included 16 patients (12 men and four women) aged 18-66 years (median age, 51.5 years). Explanted livers were serially sliced into 5-8-mm-thick sections to evaluate dysplastic nodules and hepatocellular carcinomas (HCCs). The Fisher exact test was performed to determine whether there was a relationship between HCC and the presence of a neoplastic HAPE-only lesion. The Mann-Whitney test was used to determine if patients with at least one neoplastic HAPE-only lesion had a larger number of non-HAPE-only lesions.

RESULTS

The 16 patients had 45 HAPE-only lesions; three (7%) of which were neoplastic, including one overt HCC, one HCC arising in a dysplastic nodule, and one dysplastic nodule. None of the remaining 42 HAPE-only lesions (93%) had correlative pathologic findings. All three neoplastic lesions seen only during the arterial phase were found in eight patients with concomitant HCC, who also had an additional 13 pathologically proved nonneoplastic HAPE-only lesions. In eight patients without HCC, none of the HAPE-only lesions were neoplastic. A concomitant non-HAPE-only neoplastic lesion was not a significant (P = .2) predictor for the presence of at least one neoplastic HAPE-only lesion. There was a preliminary but insignificant (P = .13) indication that the number of non-HAPE-only lesions tends to be higher in patients with neoplastic HAPE-only lesions.

CONCLUSION

The majority (93%) of HAPE-only lesions that are occult at T2-weighted and portal and/or equilibrium phase MR imaging are nonneoplastic, even in patients with pathologically proved HCC.

Indeterminate small, low-attenuating hepatocellular nodules on helical CT in patients with chronic liver disease: 2-year follow-up

To evaluate the clinical significance of indeterminate, small, low-attenuating nodular lesions on helical dynamic computed tomography (CT) in chronic liver diseases, CT images were reviewed retrospectively in 281 patients. Indeterminate, low-attenuating nodular lesions less than 20 mm in diameter were followed for 24 to 35 months. Of 127 nodules in 73 patients, 21 nodules turned out to be hepatocellular carcinomas (16%), 25 nodules (20%) became larger, while the remaining 81 nodules (64%) remained unchanged or disappeared. Some low-attenuating nodules larger than 10 mm in diameter may develop into hepatocellular carcinoma.

Value of contrast-enhanced sonography for the characterization of focal hepatic lesions in patients with diffuse liver disease: receiver operating characteristic analysis

OBJECTIVE

Our aim was to assess the diagnostic performance of contrast-enhanced agent detection sonographic imaging to characterize focal hepatic lesions in patients with diffuse liver disease in comparison with baseline sonographic images and to determine whether agent detection imaging can reduce the necessity of further diagnostic workup for lesion characterization.

MATERIALS AND METHODS

Contrast-enhanced sonography using 4 g of Levovist at a concentration of 300 mg/mL was performed on 75 focal hepatic lesions in 75 patients with diffuse liver disease. Interval reviews for both baseline without and with contrast-enhanced sonography were performed independently by two radiologists. They were requested to determine the malignity of focal hepatic lesions using a 5-point confidence level and to record the specific diagnoses and the necessity for further imaging for lesion characterization. Radiologists' performances for lesion differentiation using baseline and contrast-enhanced sonography were evaluated using receiver operating characteristic (ROC) analysis. Interobserver agreement was also analyzed.

RESULTS

When contrast-enhanced sonography was used, ROC analysis revealed a significant improvement for both reviewers (area under the receiver operating characteristic curve [A(z)] = 0.753 and 0.830 and 0.971 and 0.974 at baseline sonography and contrast-enhanced sonography, respectively; p < 0.002) for differentiating malignant and benign focal liver lesions. Contrast-enhanced sonography also improved specificity from 12% to 91% for reviewer 1 and from 26% to 85% for reviewer 2 compared with baseline sonography. Furthermore, excellent interobserver agreement was achieved for contrast-enhanced sonography (weighted kappa = 0.919), whereas only good agreement was achieved for baseline sonography (weighted kappa = 0.656). A better result for specific diagnosis was obtained by contrast-enhanced sonography (79% and 75%) than by baseline sonography (37% and 48%, p < 0.05). Contrast-enhanced sonography (72% and 63%) outperformed baseline sonography (35% and 28%, p < 0.05) as a confirmatory imaging technique.

CONCLUSION

Contrast-enhanced agent detection sonography can be used to characterize focal hepatic lesions in patients with diffuse liver disease reliably and with a higher diagnostic confidence than baseline sonography. Furthermore, contrast-enhanced sonography reduced the need for further diagnostic workups for focal hepatic lesion characterization.

Sonography-Guided Percutaneous Microwave Ablation of High-Grade Dysplastic Nodules in Cirrhotic Liver

OBJECTIVE

Our objective was to evaluate the effect of sonography-guided percutaneous microwave ablation of high-grade dysplastic nodules in the cirrhotic liver.

MATERIALS AND METHODS

From July 1997 to May 2003, 49 histologically proven high-grade dysplastic nodules in 30 patients with liver cirrhosis were treated by microwave ablation. Three patients had concomitant small hepatocellular carcinomas (D < 3.0 cm), whereas another three had undergone liver segmentectomy for hepatocellular carcinoma 1 year earlier. The mean size of the nodules was 1.8 cm (range, 0.9-4.6 cm). Sixty-eight insertions with 78 applications were administered to the 49 nodules.

RESULTS

The follow-up period was 12-82 months (mean, 45.1 +/- 19.0 months). Five patients died during this study: three from advanced hepatocellular carcinoma, one from bleeding in the upper gastrointestinal tract, and another from cerebral hemorrhage. All nodules showed decreased density on unenhanced CT and no enhancement on contrast-enhanced CT after microwave ablation. Posttreatment biopsy performed in 16 patients with 18 nodules 1-3 months after microwave ablation showed no evidence of viable tissue but replacement by fibrotic tissue in all nodules.

CONCLUSION

Percutaneous microwave ablation as a minimally invasive therapy is effective for ablating high-grade dysplastic nodules, thus preventing their potential malignant transformation, which may improve survival. The preliminary data warrant further prospective, randomized studies.

Imaging diagnosis of hepatocellular carcinoma with differentiation from other pathology

Recent advances in liver imaging techniques and better understanding of imaging findings have facilitated the detection and characterization of hepatocellular nodules in a cirrhotic liver. It is important to recognize that various types of benign nodules and pseudolesions are identified on all imaging scans performed for the diagnosis of hepatocellular carcinoma. An accurate differentiation between them is critical for adequate management of cirrhotic patients. Unfortunately, any of the imaging tests and even percutaneous biopsy are not diagnostic for borderline lesions. Intimate collaboration of hepatologists, pathologists, surgeons, and radiologists with reasonable imaging and clinical criteria estimating the degree of malignancy is imperative.

Detection of hepatocellular carcinoma: comparison of Gd-DTPA- and ferumoxides-enhanced MR imaging

The aim was to compare the diagnostic performance of dynamic Gd-DTPA- and ferumoxides-enhanced MRI for hepatocellular carcinoma (HCC). Twenty-five patients with chronic hepatitis or liver cirrhosis underwent both dynamic gadopentetate- and ferumoxides-enhanced MRI studies of the liver for HCC detection on the same day. MR data of both studies were retrospectively and independently analyzed. Two observers determined in consensus the grade of diffuse fibrotic liver changes (mild, moderate or severe) and the number of focal lesions. HCCs were confirmed by histology (n=22) and/or follow-up studies for at least six months (n=64). Differences in results obtained from both MR data sets were tested for significance with the McNemar's test (p<0.05). Ferumoxides-enhanced MR images detected 84 of 99 hepatic lesions, including 82 of 86 HCCs and 2 false positive, nonmalignant lesions, while Gd-DTPA-enhanced MR images detected 92 of 99 hepatic lesions, including 81 of 86 HCCs and 11 false positive, nonmalignant lesions. Sensitivity of MRI for detection of HCCs was not significantly different between ferumoxides-enhanced (95.3%; p>0.05) and Gd-DTPA-enhanced scans (94.2%). Gd-DTPA- and ferumoxides-enhanced MRI perform equally well for HCC detection. The majority of small hypervascular hepatic lesions, detected on dynamic Gd-DTPA-enhanced MRI but not on ferumoxides-enhanced MRI, represent no HCCs.

Dynamic Subtraction Magnetic Resonance Imaging of Cirrhotic Liver

PURPOSE

The purpose of this work was to determine the technical feasibility and value of dynamic subtraction (postcontrast-precontrast) magnetic resonance (MR) imaging for the assessment of hyperintense lesions on precontrast T1-weighted images in the cirrhotic liver.

METHODS

One hundred four hyperintense lesions on T1-weighted precontrast and arterial phase postcontrast images were subjected to analysis of their subtraction qualities depending on the lesion size, location and/or the degree of misregistration between the source images in 27 different MR imaging sets.

RESULTS

The quality of subtraction images was always diagnostic for lesions larger than 2 cm in diameter (n=8) but not diagnostic for 73% (40 of 55 lesions) of small subcentimetric lesions. Thirty-one subcapsular lesions always showed a variable degree of coregistration artifact. Only 3 of 35 lesions with a slice misregistration of 3 mm or more gave rise to subtraction images of diagnostic quality. For determining the contrast enhancement, the area under the receiver operating characteristic curve of 30 verified lesions was significantly larger (P <0.001) for subtraction images than for conventional arterial phase images.

CONCLUSION

Depending on the lesion size and/or location or the degree of misregistration between the source images, dynamic subtraction MR imaging can be useful for the characterization of hyperintense lesions on precontrast T1-weighted imaging.

Unique hypervascular nodules in alcoholic liver cirrhosis: identical to focal nodular hyperplasia-like nodules?

BACKGROUND/AIMS

Currently, focal nodular hyperplasia (FNH)-like nodules in cirrhotic liver is spotlighted. Unique hypervascular nodules mimicking FNH-like nodule in alcoholic liver cirrhosis were clinicopathologically clarified.

METHODS

Six resected and six biopsy cases of small hypervascular nodules found in alcoholic cirrhosis were studied clinicopathologically.

RESULTS

All cases were male and consumed 90-150 g/day of ethanol for longer than 20 years, and hepatitis virus markers were negative. The nodules, 9-21 mm in diameter, were detected by ultrasonography during follow-up of alcoholic cirrhosis, and showed hypervascularity on angiography. Six patients were diagnosed as hepatocellular carcinoma and six were as hyperplastic nodule by biopsy, and the former six cases received partial hepatectomy. All of the resected nodules were completely or incompletely encapsulated. Histologically, all resected and biopsy nodules showed moderate increase of cell-density with an irregular trabecular pattern, and scar-like fibrosis with anomalous blood vessels, and unpaired arteries. All nodules showed marked or mild iron deposits in hepatocytes and/or kupffer cells, and a diffuse capillarization of the sinusoids.

CONCLUSIONS

The nodules in the present series seem to fall in the same category as FNH-like nodules in cirrhotic liver, and should be taken account in screening programs including patients with alcoholic cirrhosis.

Hepatocellular carcinoma - issues in imaging

The imaging diagnosis of hepatocellular carcinoma is challenging as benign hypervascular lesions and arterioportal shunts (pseudolesions) often mimic it. There is also overlap in the imaging appearance from dysplastic and regenerating nodules. This article addresses the above imaging problems, examines proposed non-invasive imaging criteria for the diagnosis of hepatoma and discusses the optimal imaging modality.

Fine needle biopsy of focal liver lesions: the hepatologist's point of view

Guided biopsy of hepatocellular carcinoma has been recently discussed again due to the progress of imaging techniques and the risk of malignant seeding after the procedure. Ultrasound is probably still the most accurate imaging modality for early detection of nodules arising on cirrhosis, even when compared with more advanced imaging techniques. It can be easily employed in the surveillance of high-risk cirrhotic patients. Ultrasound-guided biopsy has very high sensitivity and almost absolute specificity, which allows the appropriate treatment to start after a positive diagnosis. It also allows correct diagnosis of lymphomatous nodules, the incidence of which is increased in hepatitis C virus-related cirrhosis. The risk of seeding appears limited according to the currently available epidemiological data; this should be considered against the risk of false-positive diagnosis of malignancy based on imaging studies alone. Ultrasound-guided biopsy is a valuable tool also for the diagnosis of small nodules (less than 10 mm in diameter). The best accuracy in the sampling of hepatocellular carcinoma nodules is obtained by combining smear cytology and microhistology. This can be achieved by a single biopsy with a fine cutting needle that furnishes pathologic material suitable for both examinations, reducing risks and costs.

T2-weighted MR imaging in the assessment of cirrhotic liver

PURPOSE

To assess if T2-weighted magnetic resonance (MR) imaging provides added diagnostic value in combination with dynamic gadolinium-enhanced MR imaging in the detection and characterization of nodular lesions in cirrhotic liver.

MATERIALS AND METHODS

Two readers retrospectively and independently analyzed 54 MR imaging studies in 52 patients with cirrhosis. In session 1, readers reviewed T1-weighted and dynamic gadolinium-enhanced images. In session 2, readers reviewed T1-weighted, dynamic gadolinium-enhanced, and respiratory-triggered T2-weighted fast spin-echo images. Readers identified and characterized all focal lesions by using a scale of 1-4 (1, definitely benign; 4, definitely malignant). Multireader correlated receiver operating characteristic (ROC) analysis was employed to assess radiologist performance in session 2 compared with session 1. The difference in the areas under the ROC curves for the two sessions was tested. In a third session, readers assessed conspicuity of biopsy-proved lesions on T2-weighted MR images by using a scale of 1-3 (1, not seen; 3, well seen) and identified causes of reduced conspicuity.

RESULTS

Two additional benign lesions were detected by each reader in session 2. Fifty-five lesions had pathologic verification, including 32 malignant, three high-grade dysplastic, and 20 benign nodules. There was no significant difference in the area under the ROC curves between the two sessions (P =.48). Thirty-two lesions were inconspicuous on T2-weighted MR images because of parenchymal heterogeneity, breathing artifacts (particularly in patients with ascites), and lesion isointensity with liver parenchyma. T2-weighted MR imaging was useful in the evaluation of cysts and lymph nodes.

CONCLUSION

T2-weighted MR imaging does not provide added diagnostic value in the detection and characterization of focal lesions in cirrhotic liver.

Improved diagnosing of small hepatocellular carcinomas by echo-enhanced power Doppler sonography in patients with cirrhosis

BACKGROUND AND AIMS

Echo-enhanced power Doppler sonography is an increasingly used procedure for the differentiation of liver tumours. The aim of this prospective study was to investigate the accuracy of echo-enhanced power Doppler sonography in comparison with conventional ultrasound and fundamental power Doppler sonography in diagnosing hepatocellular carcinomas and regenerative nodules in patients with cirrhosis.

SUBJECTS AND METHODS

Eighty-seven patients with cirrhosis and 90 liver tumours at conventional ultrasound were included in the study, selected from 103 consecutive patients with a mean age of 60 years (range 23-87 years) who presented to our department from January 1998 through January 2002. Sonography was performed by an experienced examiner, who was unaware of the clinical diagnosis. The exact diagnosis was based upon histological evidence from biopsy examination, laboratory results, and/or a follow-up of at least 18 months.

RESULTS

There were 65 hepatocellular carcinomas, 21 regenerative nodules, and four metastases in the study group. Only 43% of the carcinomas (mainly nodules > 3 cm in diameter) could be classified correctly by conventional ultrasound or fundamental power Doppler sonography. However, 46% of the malign lesions (mainly nodules < 3 cm in diameter) were not differentiable. All non-differentiable tumours were classified correctly by echo-enhanced power Doppler sonography. The overall sensitivity of echo-enhanced power Doppler sonography with respect to diagnosing hepatocellular carcinoma was 89%; its specificity was 60%. The corresponding values for regenerative nodules were 71% and 100%, respectively.

CONCLUSIONS

Only hepatocellular carcinomas greater than 3 cm in size can be diagnosed with a high accuracy by conventional ultrasound or fundamental power Doppler sonography. However, small malignant lesions in cirrhotic livers are often not differentiable with these techniques. With echo-enhanced power Doppler sonography, the differentiation of small hepatocellular carcinomas can be improved. However, histology is the standard of reference.

Impact of large regenerative, low grade and high grade dysplastic nodules in hepatocellular carcinoma development

BACKGROUND/AIMS

The natural outcome of ultrasound-detected macronodules in cirrhosis is still poorly understood. In this study we assessed the incidence and predictors of malignant transformation in a prospective study of 90 consecutive ultrasound-detected macronodules in cirrhosis.

METHODS

Macronodules classification was based on recently proposed histological criteria. Extranodular large (LCC) and small cell changes were also evaluated. The follow-up included ultrasound and serum alfa-fetoprotein determination every 3 months. Independent predictors of hepatocellular carcinoma were evaluated by Cox proportional hazards regression analysis.

RESULTS

During a mean follow-up of 33 months, 28 (31%) nodules transformed into hepatocellular carcinoma. The incidence of hepatocellular carcinoma per 100 person-years of follow-up was 11.3%, with a malignant transformation rate of 3.5, 15.5, 31 and 48.5% at 1, 2, 3, and 5 years respectively. High-grade dysplastic nodules (HGDN) (hazard risk=2.4; CI 95%=1.1-5.0) and LCC (hazard risk=3.1; CI 95%=1.2-7.8) were independent predictors of malignant transformation. Eight additional hepatocellular carcinomas developed outside the original lesions raising the overall malignant transformation rate to 40% while 15 macronodules (17%) became undetectable at ultrasound (US).

CONCLUSIONS

Macronodules characterize a cirrhotic subpopulation with high risk of hepatocellular carcinoma. HGDN and LCC are strong predictors of malignant transformation; subjects with simultaneous presence of both these two conditions are at highest risk of cancer development. The management of cirrhotics with macronodules should be based on morphologic features detected on liver microsamples.

Pretransplantation evaluation of the cirrhotic liver with explantation correlation: accuracy of CT arterioportography and digital subtraction hepatic angiography in revealing hepatocellular carcinoma

OBJECTIVE

The aim of this study was to determine the accuracy of CT arterioportography and hepatic digital subtraction angiography, separately and combined, for the detection of hepatocellular carcinoma in the cirrhotic liver by using thin-section liver explant histopathologic findings.

SUBJECTS AND METHODS

Fifty-nine patients with liver cirrhosis were examined with CT arterioportography and digital subtraction angiography as a part of preoperative diagnostic workup for liver transplantation. Before liver explantation, CT arterioportograms and digital subtraction angiograms were prospectively evaluated in a blinded manner, separately by two CT radiologists and two angiographers, respectively, and combined by two reviewer teams, each including a CT radiologist and an angiographer. In addition, each examination was retrospectively evaluated using direct comparison with the corresponding thin-section liver explant specimens

RESULTS

There were 39 histologically confirmed hepatocellular carcinomas. In both prospective and retrospective assessments, the reviewers achieved the best performance with CT arterioportography and digital subtraction angiography combined (area under the curve [A(z)] 0.82). The diagnostic confidence in the detection of hepatocellular carcinoma was higher with digital subtraction angiography (A(z), 0.81) than that with CT arterioportography (A(z), 0.68). Prospectively, sensitivity and specificity were 75% and 60% for CT arterioportography, 77% and 80% for digital subtraction angiography, and 84% and 81% for CT arterioportography and digital subtraction angiography combined, respectively. Retrospectively, sensitivity and specificity were 80% and 62% for CT arterioportography; 82% and 79% for digital subtraction angiography; 87% and 81% for CT arterioportography and digital subtraction angiography combined, respectively. Five hepatocellular carcinomas, one poorly and four well differentiated, with a mean size of 1.4 cm were not detectable on the CT arterioportography and digital subtraction angiography combination. False-positive findings were 20, 11, and 10 on CT arterioportography, digital subtraction angiography, and the CT arterioportography and digital subtraction angiography combination.

CONCLUSION

Combining CT arterioportography with digital subtraction angiography enabled reliable detectability of moderately and poorly differentiated hepatocellular carcinomas in cirrhotic livers but was less sensitive for the detection of well-differentiated hepatocellular carcinomas and resulted in a relatively high rate of false-positive findings.

CT during hepatic arteriography and portography: an illustrative review

The combination of computed tomography (CT) during arterial portography (CTAP) and CT during hepatic arteriography (CTHA) has been used for evaluation of hepatic neoplasms before partial hepatic resection. Focal hepatic lesions that can be demonstrated with CTAP and CTHA include regenerative nodules, dysplastic nodules, dysplastic nodules with malignant foci, hepatocellular carcinoma, cholangiocarcinoma, hemangioma, and metastases. CTAP is considered the most sensitive modality for detection of small hepatic lesions, particularly small hepatic tumors such as hepatocellular carcinoma and metastatic tumors. CTHA can demonstrate not only hypervascular tumors but also hypovascular tumors and can help differentiate malignant from benign lesions. However, various types of nontumorous hemodynamic changes are frequently encountered at CTAP or CTHA and appear as focal lesions that mimic true hepatic lesions. Such hemodynamic changes include several types of arterioportal shunts, liver cirrhosis, Budd-Chiari syndrome, inflammatory changes, pseudolesions due to an aberrant blood supply, and laminar flow in the portal vein. Familiarity with the CTAP and CTHA appearances of various hepatic lesions and nontumorous hemodynamic changes allows the radiologist to improve the diagnostic accuracy.

Detection of hypervascular hepatocellular carcinoma: comparison of SPIO-enhanced MRI with dynamic helical CT

PURPOSE

The purpose of this study was to compare the diagnostic performance of superparamagnetic iron oxide (SPIO)-enhanced MRI for the detection of hypervascular hepatocellular carcinoma (HCC) with dynamic helical CT.

METHODS

SPIO-enhanced MR and dynamic helical CT images obtained from 41 patients with 52 hypervascular HCCs (5-130 mm; mean, 27 mm) were retrospectively analyzed. MRI were obtained with 1.5 T scanners using T2-weighted and proton density-weighted spin-echo (or fast spin-echo) sequences for all cases and a T2*-weighted gradient echo sequence for 36 cases. Four blinded observers reviewed images independently. Diagnostic accuracy was evaluated using alternative-free response receiver operating characteristic (AFROC) method. Sensitivities and positive predictive values (PPV) were also evaluated.

RESULTS

The areas under the AFROC curves for each observer were greater for MR than for CT (means, 0.81 and 0.76; p < 0.05). The mean sensitivities for MR and CT were 0.75 and 0.71, respectively (p = 0.13). The mean PPVs were 0.83 and 0.79 (p = 0.21).

CONCLUSION

SPIO-enhanced MRI showed slightly better diagnostic performance than dynamic helical CT for the detection of hypervascular HCCs.

Diagnosis of hepatic neoplasms using CT arterial portography and CT hepatic arteriography

Both computed tomography arterial portography (CTAP) and CT hepatic arteriography (CTHA) are CT techniques with angiographic assistance. The detection sensitivity of these techniques is high because marked lesion contrast can be obtained using direct delivery of contrast materials to the liver parenchyma or the tumors. The use of CTAP and CTHA may improve therapeutic results after transarterial embolization therapy for hepatocellular carcinomas because of their high diagnostic accuracy. Findings on CTAP or CTHA can sometimes help characterize the hepatic focal lesions. Thus, CTAP and CTHA are frequently performed as pretreatment examinations, although they are invasive compared to intravenous (IV) contrast-enhanced CT or magnetic resonance imaging. However, there are some potential pitfalls, such as nontumorous perfusion abnormalities. CTAP and CTHA are less effective for evaluation of patients with cirrhosis and portal hypertension. This article presents a current overview of CTAP and CTHA technique for diagnosis of hepatic neoplasms.

Hepatic nodules with early enhancement during computed tomography portography: report of six cases

AIM

To study the clinicopathologic characteristics of hepatic nodular lesions with high attenuation (increased portal blood flow) compared with surrounding hepatic parenchyma on computed tomography (CT) during arterial portography (CTAP).

METHODS

For six lesions found in six patients demonstrated as a high-attenuated mass by CTAP, CT during hepatic arteriography (CTHA; n = 3 patients), digital subtraction hepatic arteriography (n = 6) and conventional helical CT (n = 6) were evaluated retrospectively and compared with histopathologic findings (n = 4). Pathologic diagnosis was atypical adenomatous hyperplasia, nodule-in-nodule hepatocellular carcinoma (HCC) in one resected lesion each and overt HCC in two biopsied lesions. Two patients did not undergo any therapy and were followed up.

RESULTS

The average size of lesions was 2.2 cm (range 1.2-3.5 cm). The CTAP revealed high attenuation in all six lesions; entirely within the lesion (n = 4 lesions) or peripherally with a central low attenuation (n = 2). In contrast, CTHA showed low attenuated lesions; entirely within the mass (n = 2) or peripherally with a central high-attenuated spot (n = 1). Hepatic arteriogram revealed only two hypervascular lesions; entirely and partially in one each. In the arterial phase of helical CT, all but one lesion were iso- or hypo-attenuated. In two patients who were followed up to 39 and 55 months without therapy, neither tumor growth nor hemodynamic change of the lesion was recognized on CT.

CONCLUSIONS

Even though the incidence of hepatic nodular lesions demonstrated as high attenuating on CTAP is low, all but one lesion in the current series showed iso- or hypo-attenuation on CTHA and/or helical CT, suggesting the hemodynamics are reciprocal between CTAP and CTHA. One exceptional lesion that showed high attenuation on both CTAP and conventional CT was pathologically advanced HCC. Based on the follow-up study of two untreated patients, this kind of lesion with high attenuation on CTAP seems to grow slowly.

Contrast agents for hepatic magnetic resonance imaging

The current availability of liver-specific contrast media (LSCM) allows the possibility to obtain an accurate diagnosis when studying focal liver lesions (FLL). It is necessary to have an in-depth knowledge of the biologic and histologic characteristics of FLL and the enhancement mechanism of LSCM to gain significant accuracy in the differential diagnosis of FLL. It is possible to subdivide FLL into three main groups according to the kinetics of contrast enhancement: hypervascular FLL, hypovascular FLL, and FLL with delayed enhancement. Dynamic contrast-enhanced magnetic resonance imaging is an important tool in the identification and characterization of FLL. LSCM with a first phase of extracellular distribution give both dynamic (morphologic) and late phase (functional) information useful for lesion characterization. With LSCM it is possible to differentiate with high accuracy benign from malignant lesions and hepatocellular from nonhepatocellular lesions. To understand contrast behavior after injection of LSCM, it is necessary to correlate contrast enhancement with the biologic and histologic findings of FLL.