Intraindividual comparison of gadoxetate disodium-enhanced MR imaging and 64-section multidetector CT in the Detection of hepatocellular carcinoma in patients with cirrhosis

Clinical utility of imaging for evaluation of hepatocellular carcinoma

The hemodynamics of a hepatocellular nodule is the most important imaging parameter used to characterize various hepatocellular nodules in liver cirrhosis, because sequential changes occur in the feeding vessels and hemodynamic status during hepatocarcinogenesis. Therefore, the imaging criteria for hepatocellular carcinoma (HCC) are also usually based on vascular findings, eg, early arterial uptake followed by washout in the portal venous and equilibrium phases. Contrast-enhanced ultrasonography, dynamic multidetector-row computed tomography (MDCT), and dynamic magnetic resonance (MR) imaging with gadopentetate dimeglumine (Gd-DTPA) are useful for detecting hypervascular HCC on the basis of vascular criteria but are not as useful for hypovascular HCC. Contrast-enhanced MR imaging with gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA), a hepatocyte-specific MR contrast agent, is superior to dynamic MDCT and dynamic MR imaging with Gd-DTPA in detecting both hypervascular and hypovascular HCC. Moreover, Gd-EOB-DTPA-enhanced MR imaging can display each histologically differentiated HCC as hypointense relative to the liver parenchyma. ¹⁸F-fluorodeoxyglucose positron emission tomography imaging might not be suitable for the screening and detection of HCC, given its lower diagnostic performance. However, this technique plays an important role in determining whether HCC has spread beyond the liver.

Natural course of hypovascular nodules detected on gadoxetic acid-enhanced MR imaging: presence of fat is a risk factor for hypervascularization

PURPOSE

Hypovascular nodules that exhibit hypointensity in hepatocyte-phase images of gadoxetic acid-enhanced magnetic resonance (MR) imaging are frequently encountered in clinical practice. We investigated risk factors for the development of these nodules into hypervascular hepatocellular carcinoma (HCC).

METHODS

We retrospectively reviewed our institutional database and identified 302 patients who underwent gadoxetic acid-enhanced MR imaging for suspected or confirmed HCC from February 1, 2008 to January 30, 2011. We excluded patients who were examined for metastasis of other malignancies or for other hepatic tumors, such as focal nodular hyperplasia. We identified hypovascular nodules that were hypointense in hepatocyte-phase images, recorded their characteristics, and calculated the cumulative hypervascularization rate for nodules that were followed up.

RESULTS

Of the 302 patients, 82 had hypovascular nodules (178 nodules; mean size, 9.3 mm). Sixty nodules were followed up for over 6 months, and eight progressed to hypervascular HCC. Hypervascularization occurred more frequently in nodules with fat than those without (P<0.01). The cumulative hypervascularization rate was 5.1% over a year.

CONCLUSION

The presence of intralesional fat was found to be a risk factor for hypervascularization of hypovascular nodules that exhibited hypointensity in the hepatocyte-phase images of gadoxetic acid-enhanced MR imaging.

Solid liver masses: approach to management from the standpoint of a radiologist

Solid liver masses are being discovered at increasing rates due to the widespread use of medical imaging. Ultrasound, computed tomography, and magnetic resonance imaging play important and often complementary roles in detecting and diagnosing solid liver masses. Morphologic and enhancement characteristics as well as clinical history frequently allow a confident imaging diagnosis. Still, diagnosing liver masses with imaging alone remains a challenge, and masses that do not meet specific diagnostic criteria may require biopsy. Newly developed standardized terminology and imaging criteria have facilitated the imaging diagnosis of hepatocellular carcinoma (HCC) in patients with cirrhosis. Hepatobiliary-secreted MRI contrast agents have improved the ability to diagnose focal nodular hyperplasia and may also improve the detection and imaging diagnosis of HCC. These exciting new contrast agents are the subject of active investigation.

Gadoxetic acid-enhanced MRI for T-staging of gallbladder carcinoma: emphasis on liver invasion

OBJECTIVE

To evaluate the diagnostic performance of gadoxetic acid-enhanced MRI with an emphasis on the usefulness of the hepatobiliary phase (HBP) in T-staging of gallbladder carcinoma.

METHODS

66 patients with surgically confirmed gallbladder carcinoma underwent MRI. Two radiologists independently reviewed two sets of gadoxetic acid-enhanced MRI without and with the HBP. Local tumour spread was evaluated according to T-staging, and the results were compared with pathological findings. The diagnostic performance of two image sets to differentiate each T-stage was compared.

RESULTS

The sensitivities of MRI with the HBP to differentiate T1 vs ≥ T2 lesions, ≤ T2 vs ≥ T3 lesions and ≤ T3 vs T4 lesions were 96.3%, 85.7% and 100% for Observer 1 and 92.6%, 95.2% and 100% for Observer 2, respectively (p<0.0001). By adding the HBP, the sensitivities to differentiate ≤ T2 vs ≥ T3 lesions were increased from 66.7% to 85.7% for Observer 1 and from 81.0% to 95.2% for Observer 2, although there was no significant difference (p>0.05). The overall accuracies for T-staging were increased from 80.3% to 86.4% for Observer 1, a statistically significant degree (p=0.046), and from 83.8% to 87.9% for Observer 2 (p>0.05). The k-value for the two observers indicated excellent agreement.

CONCLUSION

Gadoxetic acid-enhanced MRI provided acceptable diagnostic performance for T-staging of gallbladder carcinoma. Addition of the HBP aids in the detection of liver invasion.

ADVANCES IN KNOWLEDGE

In the T-staging of gallbladder carcinoma, gadoxetic acid-enhanced MRI with the HBP may enhance detection of liver invasion.

Surveillance of HCC Patients after Liver RFA: Role of MRI with Hepatospecific Contrast versus Three-Phase CT Scan-Experience of High Volume Oncologic Institute

Purpose. To compare the diagnostic accuracy of hepatospecific contrast-enhanced MRI versus triple-phase CT scan after radiofrequency ablation (RFA) in hepatocellular carcinoma (HCC) patients. Methods. Thirty-four consecutive HCC patients (42 hepatic nodules) were treated with percutaneous RFA and underwent MR and CT scans. All patients were enrolled in a research protocol that included CT with iodized contrast medium injection and MR with hepatospecific contrast medium injection. All patients were restaged within four weeks and at 3 months from ablation. The images were reviewed by four different radiologists to evaluate tumor necrosis, residual or recurrence disease, and evidence of new foci. Results. Thirty-two nodules were necrotic after treatment; 10 showed residual disease. Six new HCCs were identified. At first month followup CT has identified 34 necrotic lesions and 8 residual diseases; no new foci were recognized. At MRI instead, 32 complete necrotic lesions were identified, 10 lesions showed residual disease, and 2 new HCCs were found. At three months, CT demonstrated 33 completely necrotic lesions, 9 residual diseases, and 2 new HCCs. MR showed 31 complete necrotic lesions, 11 cases of residual disease, and 6 new HCCs. Conclusions. Hepatospecific contrast-enhanced MRI is more effective than multiphase CT in assessment of HCC treated with RFA.

Consensus report from the 6th International forum for liver MRI using gadoxetic acid

As the utility of liver-specific magnetic resonance imaging (MRI) increases, it is pertinent to optimize and expand protocols to improve accuracy and foster evolution of techniques; in turn, positive impacts should be seen in patient management. This article reports on the latest expert thinking and current evidence in the field of liver-specific MRI, as discussed at the 6(th) International Forum for Liver MRI, which was held in Vancouver, Canada in September 2012. Topics discussed at this forum described the use of gadoxetic acid-enhanced MRI for the assessment of liver function at the segmental level; to increase accuracy in the diagnosis of liver metastases; to overcome current challenges in patients with cirrhosis, including management of arterial hypo-/isovascular, hepatobiliary phase hypointense nodules; and the data which would be required in order to recommend the use of this modality in hepatocellular carcinoma management guidelines. Growing evidence suggests that gadoxetic acid-enhanced MRI can help to improve the management of patients with a number of different liver disorders; however, more data are needed in some areas, and there may be a case for developing an interpretation guideline for gadoxetic acid-enhanced MRI findings to aid standardization.

Assessing patients with hepatocellular carcinoma meeting the Milan criteria: Is liver 3 tesla MR with gadoxetic acid necessary in addition to liver CT?

PURPOSE

To determine the added value of 3 Tesla liver MR in patients with hepatocellular carcinoma (HCC) within the liver computed tomography (CT) -based Milan criteria.

MATERIALS AND METHODS

Liver CT and MR images of 130 patients with HCC within the Milan criteria based on liver CT were retrospectively reviewed. The number of MR-diagnosed HCCs and that of high risk hypervascular nodules (HRHNs), the effect of obtaining MR on patient management and CT appearances of MR-diagnosed HCCs and those of HRHNs were evaluated. Independent predictor for diagnosing additional HCCs on liver MR was analyzed.

RESULTS

A total of 18.5% (24/130) of patients had additional 39 HCCs on MR, with a 5.4% (7/130) dropout rate from the Milan criteria. 28.5% (37/130) of patients had additional 78 HRHNs. Overall, 39.2% (51/130) of patients required changes in management. The common CT appearances of MR-diagnosed HCCs were arterial enhancing lesions ≥ 0.5cm (38.4%, 15/39), low density nodules < 1.5 cm (30.8%, 12/39) and invisibility (28.2%, 11/39). For MR-diagnosed HRHNs, 55.1% (43/78) were invisible on CT. The presence of inconclusive lesions on CT was an independent predictor for diagnosing additional HCCs on MR.

CONCLUSION

For patients with HCCs within the Milan criteria on liver CT, liver MR may be necessary to detect additional HCCs and HRHNs.

Biologic factors affecting HCC conspicuity in hepatobiliary phase imaging with liver-specific contrast agents

OBJECTIVE

The purpose of this study was to evaluate factors influencing hepatic enhancement and the conspicuity of hepatocellular carcinoma (HCC) on gadobenate dimeglu-mine- and gadoxetate disodium-enhanced hepatobiliary phase MR images.

MATERIALS AND METHODS

Patients with chronic liver disease who underwent liver MRI with gadobenate dimeglumine (n = 93) or gadoxetate disodium (n = 92) were included in this study. The degree of hepatic enhancement on 1-hour and 3-hour delayed phase gadobenate dimeglumine-enhanced and 20-minute delayed phase gadoxetate disodium-enhanced hepatobiliary phase images were evaluated with quantitative and visual indexes. The conspicuity of 40 HCCs in the gadobenate dimeglumine group and 38 HCCs in the gadoxetate disodium group were graded on a 5-point scale. Correlation between hepatic enhancement indexes and clinical factors (age, body weight, serum bilirubin concentration, model for end-stage liver disease score, Child-Pugh class, and renal function stage) and association between the conspicuity of HCCs and clinical factors, lesion diameter, and hepatic enhancement indexes were evaluated.

RESULTS

In the gadobenate dimeglumine group, the visual index of hepatic enhancement independently correlated with Child-Pugh class on both 1- and 3-hour delayed images (p < 0.001) and with renal function stage only on 3-hour delayed images (p ≤ 0.031). In the gadoxetate disodium group, both quantitative and visual indexes of hepatic enhancement independently correlated with Child-Pugh class (p ≤ 0.019). The conspicuity of HCCs independently correlated with Child-Pugh class and lesion diameter on 3-hour delayed gadobenate dimeglumine-enhanced images (p ≤ 0.031) and on gadoxetate disodium-enhanced images (p = 0.033) and significantly correlated with the visual index of hepatic enhancement on both gadobenate dimeglumine- and gadoxetate disodium-enhanced images (p ≤ 0.001).

CONCLUSION

Liver enhancement and conspicuity of HCC are significantly affected by Child-Pugh class on both gadobenate dimeglumine- and gadoxetate disodium-enhanced hepatobiliary phase MR images.

Hepatic steatosis: effect on hepatocyte enhancement with gadoxetate disodium-enhanced liver MR imaging

PURPOSE

To investigate the effect of hepatic steatosis on enhancement of liver parenchyma with gadoxetate disodium-enhanced MR imaging.

MATERIALS AND METHODS

Gadoxetate disodium-enhanced MR images of 166 patients were analyzed. Liver-spleen contrast and liver-spleen relative enhancement ratio on three-dimensional gradient echo T1-weighted images with fat suppression 20 minutes after injection of gadoxetate disodium were evaluated in correlation with fat signal fraction using the Pearson correlation coefficient and also compared between patients with normal liver parenchyma (n = 115) and with liver steatosis (n = 51) using the Student t-test.

RESULTS

The liver-spleen contrast at hepatobiliary phase showed inverse correlations with the fat signal fraction (r = -0.36; P < 0.01), while the liver-spleen relative enhancement ratio showed no statistical correlation with the fat signal fraction (P = 0.80). The liver-spleen contrast in the group with steatotic liver was significantly lower than that in the group with normal livers (P < 0.001). There was no significant difference in the relative enhancement ratio between the two groups (P = 0.85).

CONCLUSION

Our results may suggest that hepatic steatosis does not affect the uptake of gadoxetate disodium into hepatocytes and are considered crucial as background knowledge in extending the use of gadoxetate disodium-enhanced MR imaging to quantitate liver function.

Gadoxetic acid disodium-enhanced magnetic resonance imaging for the detection of hepatocellular carcinoma: a meta-analysis

OBJECTIVE

To determine the accuracy of MR imaging with gadoxetic acid disodium (Gd-EOB-DTPA) for the detection of hepatocelluar carcinoma (HCC).

MATERIALS AND METHODS

A systematic search was performed in PUBMED, EMBASE, Web of Science, Cochrane Library and the Chinese Biomedical Literature Database up to March 2013 to identify studies about evaluation of Gd-EOB-DTPA enhanced MR imaging in patients suspected of having HCC. The data were extracted to perform heterogeneity test and threshold effect test and to calculate sensitivity, specificity, diagnostic odds ratio, predictive value, and areas under summary receiver operating characteristic curve (AUC).

RESULTS

From 601 citations, 10 were included in the meta-analysis. The methodological quality of the 10 studies was good. Overall HCC: There was significant heterogeneity in the pooled analysis (I(2) = 69.4%, P = 0.0005), and the pooled weighted values were determined to be sensitivity: 0.91 (95% confidence interval (CI): 0.89, 0. 93); specificity: 0.95 (95% CI: 0.94, 0.96); diagnostic odds ratio: 169.94 (95% CI: 108.84, 265.36); positive likelihood ratio: 15.75 (95% CI: 7.45, 33.31); negative likelihood ratio: 0.10 (95% CI: 0.06, 0.15). The AUC was 0.9778. HCC in cirrhosis: The estimates were to be sensitivity: 0.91 (95% CI: 0.88, 0.93); specificity: 0.93 (95% CI: 0.89, 0.95); diagnostic odds ratio: 234.24 (95% CI: 33.47, 1639.25); positive likelihood ratio: 15.08 (95% CI: 2.20, 103.40); negative likelihood ratio: 0.08 (95% CI: 0.03, 0.21). The AUC was 0.9814. ≤20 mm HCC: The AUC was 0.9936. There was no notable publication bias.

CONCLUSIONS

This meta-analysis suggests that MR imaging with Gd-EOB-DTPA has high diagnostic accuracy for the detection of HCC, especially for ≤20 mm HCC. This technique shows good prospect in diagnosis of HCC.

Gadoxetate uptake as a possible marker of hepatocyte damage after liver resection-preliminary data

AIM

To determine the feasibility of evaluating surgically induced hepatocyte damage using gadoxetate disodium (Gd-EOB-DTPA) as a marker for viable hepatocytes at magnetic resonance imaging (MRI) after liver resection.

MATERIAL AND METHODS

Fifteen patients were prospectively enrolled in this institutional review board-approved study prior to elective liver resection after informed consent. Three Tesla MRI was performed 3-7 days after surgery. Three-dimensional (3D) T1-weighted (W) volumetric interpolated breath-hold gradient echo (VIBE) sequences covering the liver were acquired before and 20 min after Gd-EOB-DTPA administration. The signal-to-noise ratio (SNR) was used to compare the uptake of Gd-EOB-DTPA in healthy liver tissue and in liver tissue adjacent to the resection border applying paired Student's t-test. Correlations with potential influencing factors (blood loss, duration of intervention, age, pre-existing liver diseases, postoperative change of resection surface) were calculated using Pearson's correlation coefficient.

RESULTS

Before Gd-EOB-DTPA administration the SNR did not differ significantly (p = 0.052) between healthy liver tissue adjacent to untouched liver borders [59.55 ± 25.46 (SD)] and the liver tissue compartment close to the resection surface (63.31 ± 27.24). During the hepatocyte-specific phase, the surgical site showed a significantly (p = 0.04) lower SNR (69.44 ± 24.23) compared to the healthy site (78.45 ± 27.71). Dynamic analyses revealed a significantly lower increase (p = 0.008) in signal intensity in the healthy tissue compared to the resection border compartment.

CONCLUSION

EOB-DTPA-enhanced MRI may have the potential to be an effective non-invasive tool for detecting hepatocyte damage after liver resection.

Competitive advantage of PET/MRI

Multimodality imaging has made great strides in the imaging evaluation of patients with a variety of diseases. Positron emission tomography/computed tomography (PET/CT) is now established as the imaging modality of choice in many clinical conditions, particularly in oncology. While the initial development of combined PET/magnetic resonance imaging (PET/MRI) was in the preclinical arena, hybrid PET/MR scanners are now available for clinical use. PET/MRI combines the unique features of MRI including excellent soft tissue contrast, diffusion-weighted imaging, dynamic contrast-enhanced imaging, fMRI and other specialized sequences as well as MR spectroscopy with the quantitative physiologic information that is provided by PET. Most evidence for the potential clinical utility of PET/MRI is based on studies performed with side-by-side comparison or software-fused MRI and PET images. Data on distinctive utility of hybrid PET/MRI are rapidly emerging. There are potential competitive advantages of PET/MRI over PET/CT. In general, PET/MRI may be preferred over PET/CT where the unique features of MRI provide more robust imaging evaluation in certain clinical settings. The exact role and potential utility of simultaneous data acquisition in specific research and clinical settings will need to be defined. It may be that simultaneous PET/MRI will be best suited for clinical situations that are disease-specific, organ-specific, related to diseases of the children or in those patients undergoing repeated imaging for whom cumulative radiation dose must be kept as low as reasonably achievable. PET/MRI also offers interesting opportunities for use of dual modality probes. Upon clear definition of clinical utility, other important and practical issues related to business operational model, clinical workflow and reimbursement will also be resolved.

Gd-EOB-DTPA-enhanced MRI is better than MDCT in decision making of curative treatment for hepatocellular carcinoma

BACKGROUND

We assessed the change in the therapeutic decision among curative treatments after adding Gd-EOB-DTPA-enhanced MRI to triple-phase MDCT for patients with early-stage HCC.

METHODS

This study retrospectively investigated two groups: 33 pathologically confirmed HCC patients after liver transplantation in group 1; 34 HCC patients without pathology in group 2. In group 1, we simulated the therapeutic decision-making process by pretransplant MDCT and Gd-EOB-DTPA-enhanced MRI. In group 2, including the 34 early-stage HCC patients consecutively enrolled, we investigated the change of therapeutic decision after adding Gd-EOB-DTPA-enhanced MRI to MDCT.

RESULTS

In the simulation from group 1, after adding Gd-EOB-DTPA-enhanced MRI, 33.3% (11/33 patients) of treatment decisions were changed from the decision based on MDCT alone. Among 22 patients considered eligible for resection and 33 patients for radiofrequency ablation, the therapeutic decision was changed for 10 patients in the surgical group and 4 patients for the RFA group (45.5 and 12.1%). In group 2, the rate of change in the therapeutic decision after adding Gd-EOB-DTPA-enhanced MRI to MDCT was 41.2% (14/34 patients). In group 1 with explants pathology, the median diameter of HCCs not detected by MDCT but detected by Gd-EOB-DTPA-enhanced MRI was 1.15 cm (0.3-3.0 cm). The median diameter of HCCs seen only in the explanted liver was 1.0 cm (0.3-1.7 cm), and 60.7% of them were well-differentiated HCCs.

CONCLUSIONS

This study suggests that performing Gd-EOB-DTPA-enhanced MRI before deciding on curative treatment for early-stage HCC may improve the accuracy of treatment decision for early-stage HCC.

Role of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging in the management of hepatocellular carcinoma: consensus at the Symposium of the 48th Annual Meeting of the Liver Cancer Study Group of Japan

We summarize here the consensus reached at the Symposium of the 48th Annual Meeting of the Liver Cancer Study Group of Japan held in Kanazawa on July 20th and 21st, 2012, on the role of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI) in the management of hepatocellular carcinoma (HCC). Currently, dynamic CT is the first choice of imaging modality when HCC is suspected. EOB-MRI is useful for differentiation and definitive diagnosis of HCC when dynamic CT/MRI does not show conclusive findings for HCC. In addition, contrast- enhanced ultrasound with Sonazoid is useful for making a decision on whether or not to treat a hypovascular lesion <1 cm when the nodules are shown with low intensity in the hepatocyte phase of EOB-MRI. Furthermore, EOB-MRI should be performed in selected cases of HCC ultrahigh-risk groups every 3-4 months, or EOB-MRI should be performed at least once at the first visit in all HCC ultrahigh-risk groups.

Gadoxetic acid disodium-enhanced magnetic resonance imaging for the detection of hepatocellular carcinoma: a meta-analysis

OBJECTIVE

To determine the accuracy of MR imaging with gadoxetic acid disodium (Gd-EOB-DTPA) for the detection of hepatocelluar carcinoma (HCC).

MATERIALS AND METHODS

A systematic search was performed in PUBMED, EMBASE, Web of Science, Cochrane Library and the Chinese Biomedical Literature Database up to March 2013 to identify studies about evaluation of Gd-EOB-DTPA enhanced MR imaging in patients suspected of having HCC. The data were extracted to perform heterogeneity test and threshold effect test and to calculate sensitivity, specificity, diagnostic odds ratio, predictive value, and areas under summary receiver operating characteristic curve (AUC).

RESULTS

From 601 citations, 10 were included in the meta-analysis. The methodological quality of the 10 studies was good. Overall HCC: There was significant heterogeneity in the pooled analysis (I(2) = 69.4%, P = 0.0005), and the pooled weighted values were determined to be sensitivity: 0.91 (95% confidence interval (CI): 0.89, 0. 93); specificity: 0.95 (95% CI: 0.94, 0.96); diagnostic odds ratio: 169.94 (95% CI: 108.84, 265.36); positive likelihood ratio: 15.75 (95% CI: 7.45, 33.31); negative likelihood ratio: 0.10 (95% CI: 0.06, 0.15). The AUC was 0.9778. HCC in cirrhosis: The estimates were to be sensitivity: 0.91 (95% CI: 0.88, 0.93); specificity: 0.93 (95% CI: 0.89, 0.95); diagnostic odds ratio: 234.24 (95% CI: 33.47, 1639.25); positive likelihood ratio: 15.08 (95% CI: 2.20, 103.40); negative likelihood ratio: 0.08 (95% CI: 0.03, 0.21). The AUC was 0.9814. ≤20 mm HCC: The AUC was 0.9936. There was no notable publication bias.

CONCLUSIONS

This meta-analysis suggests that MR imaging with Gd-EOB-DTPA has high diagnostic accuracy for the detection of HCC, especially for ≤20 mm HCC. This technique shows good prospect in diagnosis of HCC.

Imaging of hepatocellular carcinoma: current concepts

Hepatocellular carcinoma (HCC) is the most common primary hepatic malignancy, and usually develops in the setting of liver cirrhosis. The early diagnosis of HCC is essential as curative treatment (including surgical resection and liver transplantation) improves survival. While screening and surveillance are traditionally performed with ultrasound, reported accuracies of ultrasound vary greatly, and poor sensitivity for small nodules is a uniformly recognized concern. Advances in computed tomography (CT) and magnetic resonance imaging (MRI), including multidetector technology and fast breath hold sequences now allow dynamic multiphasic enhanced imaging of the liver with excellent spatial and temporal resolution, holding much promise for improved HCC detection.

Gadoxetic acid-enhanced MRI compared with CT during angiography in the diagnosis of hepatocellular carcinoma

PURPOSE

To assess the value of gadoxetic acid-enhanced magnetic resonance imaging (MRI) for the pre-therapeutic detection of hepatocellular carcinoma (HCC) using receiver operating characteristic (ROC) analysis with the combination of computed tomography (CT) arterial portography and CT hepatic arteriography (CTAP/CTHA).

MATERIALS AND METHODS

A total of 54 consecutive patients with 87 nodular HCCs were retrospectively analyzed. All HCC nodules were confirmed pathologically. Three blinded readers independently reviewed 432 hepatic segments, including 78 segments with 87 HCCs. Each reader read two sets of images: Set 1, CTAP/CTHA; Set 2, gadoxetic acid-enhanced MRI including a gradient dual-echo sequence and diffusion-weighted imaging (DWI). The ROC method was used to analyze the results. The sensitivity, specificity, positive predictive value, negative predictive value and sensitivity according to tumor size were evaluated.

RESULTS

For each reader, the area under the curve was significantly higher for Set 2 than for Set 1. The mean area under the curve was also significantly greater for Set 2 than for Set 1 (area under the curve, 0.98 vs. 0.93; P=.0009). The sensitivity was significantly higher for Set 2 than for Set 1 for all three readers (P=.012, .013 and .039, respectively). The difference in the specificity, positive predictive values and negative predictive values of the two modalities for each reader was not significant (P>.05).

CONCLUSION

Gadoxetic acid-enhanced MRI including a gradient dual-echo sequence and DWI is recommended for the pre-therapeutic evaluation of patients with HCC.

The impact of CT follow-up interval on stages of hepatocellular carcinomas detected during the surveillance of patients with liver cirrhosis

OBJECTIVE

The purpose of our study was to assess the relationship between time intervals of CT examinations and the stages of hepatocellular carcinomas (HCCs) detected during the surveillance of patients with liver cirrhosis.

MATERIALS AND METHODS

In this study, 73 patients with 93 HCCs (reference standard: surgery, n=7 [8 HCCs]; biopsy, n=2 [3 HCCs]; imaging criteria, n=64 [82 HCCs]) who showed no evidence of HCC on prior CT examinations were included. Patients were stratified into three groups based on the time interval between the two CT examinations: groups A (interval≤1 year, n=21), B (interval between 1 and 2 years, n=25), and C (interval≥2 years, n=27). Tumor stages according to the American Joint Committee on Cancer (AJCC), the Barcelona Clinic Liver Cancer (BCLC) staging system, and the Milan criteria were evaluated retrospectively by two reviewers. The Fisher exact test was used to compare tumor stages. Spearman correlation coefficients were used to assess the correlation between the CT interval and tumor size.

RESULTS

One (4%) HCC in group B and four (15%) HCCs in group C were larger than 5 cm in diameter, whereas no tumor was larger than 3 cm in diameter in group A. There was no difference in tumor diameter between groups, but tumor size was positively correlated with time interval between examinations (Spearman correlation coefficient, 0.472; p<0.001). In group A, 19 (90%) patients had cancers categorized as T1, and the remaining patients had cancers categorized as T2. In group B, one (4%) patient had a cancer that was categorized as T3b according to the AJCC classification, in the intermediate stage according to the BCLC classification, and above the Milan criteria. In group C, three (11%) patients had T3b cancers, and five had cancers in either intermediate or higher stage and above the Milan criteria.

CONCLUSION

HCC detected on CT performed within 1 year of a negative examination was at a curable stage in patients with liver cirrhosis.

Comparison of acute transient dyspnea after intravenous administration of gadoxetate disodium and gadobenate dimeglumine: effect on arterial phase image quality

PURPOSE

To determine whether acute transient dyspnea and/or arterial phase image degradation occurs more or less often after intravenous administration of gadoxetate disodium than with intravenous administration of gadobenate dimeglumine.

MATERIALS AND METHODS

Institutional review board approval and patient consent were obtained for this prospective observational study. One hundred ninety-eight gadolinium-based contrast media administrations (99 with gadoxetate disodium [10 mL, n = 97; 8 mL, n = 1; 16 mL, n = 1] and 99 with gadobenate dimeglumine [0.1 mmol per kilogram of body weight, maximum dose, 20 mL]) for hepatobiliary indications were assessed in 192 patients. Subjective patient complaints were assessed. Objective respiratory motion degradation on T1-weighted precontrast and dynamic postcontrast (arterial, venous, or late dynamic or extracellular) magnetic resonance (MR) imaging datasets were independently assessed in a randomized, blinded fashion by five readers using a five-point scale, with mean scores of 4 or greater indicating severe motion. Comparisons between agents were made by using χ(2) or Fisher exact test, where appropriate.

RESULTS

Significantly more patient complaints of acute transient dyspnea occurred after gadoxetate disodium administration than gadobenate dimeglumine (14% [14 of 99] vs 5% [five of 99], P = .05). There were significantly more severely degraded arterial phase data sets for gadoxetate disodium than for gadobenate dimeglumine for both the general population (17% [17 of 99] vs 2% [two of 99], P = .0007) and the subpopulation with cirrhosis (19% [14 of 72] vs 3% [one of 37], P = .02). This effect did not extend to venous (1% [one of 99] vs 2% [two of 99], P > .99 [overall population]) or late dynamic or extracellular (2% [two of 99] vs 0% [zero of 99], P = .5 [overall population]) phases. No patient required treatment for self-limited dyspnea.

CONCLUSION

Intravenous gadoxetate disodium can result in acute self-limiting dyspnea that can have a deleterious effect on arterial phase MR image quality and occurs significantly more often than with intravenous gadobenate dimeglumine.

Hepatocellular carcinoma in cirrhotic patients: prospective comparison of US, CT and MR imaging

OBJECTIVES

To prospectively compare the diagnostic performance of ultrasound (US), multidetector computed tomography (MDCT) and contrast-enhanced magnetic resonance imaging (MRI) in cirrhotic patients who were candidates for liver transplantation.

METHODS

One hundred and forty consecutive patients with 163 hepatocellular carcinoma (HCC) nodules underwent US, MRI and MDCT. Diagnosis of HCC was based on pathological findings or substantial growth at 12-month follow-up. Four different image datasets were evaluated: US, MDCT, MRI unenhanced and dynamic phases, MRI unenhanced dynamic and hepatobiliary phase. Diagnostic accuracy, sensitivity, specificity, PPV and NPV, with corresponding 95 % confidence intervals, were determined. Statistical analysis was performed for all lesions and for three lesion subgroups (<1 cm, 1-2 cm, >2 cm).

RESULTS

Significantly higher diagnostic accuracy, sensitivity and NPV was achieved on dynamic + hepatobiliary phase MRI compared with US, MDCT and dynamic phase MRI alone. The specificity and PPV of US was significantly lower than that of MDCT, dynamic phase MRI and dynamic + hepatobiliary phase MRI. Similar results were obtained for all sub-group analyses, with particular benefit for the diagnosis of smaller lesions between 1 and 2 cm.

CONCLUSIONS

Dynamic + hepatobiliary phase MRI improved detection and characterisation of HCC in cirrhotic patients. The greatest benefit is for diagnosing lesions between 1 and 2 cm.

Comparison of international guidelines for noninvasive diagnosis of hepatocellular carcinoma

The aim of this review is to present the similarities and differences between the latest guidelines for noninvasive diagnosis of hepatocelullar carcinoma (HCC) of American Association for the Study of Liver Diseases (AASLD), European Association for the Study of the Liver (EASL), Asian Pacific Association for the Study of the Liver (APASL), and Japanese Society of Hepatology. All the four guidelines defined a typical HCC vascular pattern as the homogeneous hyperenhancement (wash-in) in the arterial phase followed by wash-out in the venous or late phase. The AASLD and EASL guidelines accept only four-phase computed tomography and dynamic contrast magnetic resonance imaging (MRI) for HCC diagnosis, whereas the APASL and Japanese guidelines also accept contrast-enhanced ultrasound (CEUS). Regarding CEUS, the APASL guidelines accept the use of Levovist or Sonazoid as contrast agents, whereas the Japanese guidelines accept only the use of Sonazoid. The AASLD and EASL guidelines recommend using only extracellular contrast agents such as gadolinium for MRI, whereas the APASL guidelines also included the use of super paramagnetic iron oxid-MRI, and the Japanese guidelines recommended the use of gadolinium-ethoxybenzyl-diethylentriamine pentaacetic acid-MRI. The AASLD and EASL guidelines propos a diagnostic algorithm starting from the tumor size, whereas the APASL and Japanese guidelines recommend an algorithm starting from arterial tumor vascularity (hyper- or hypovascular in the arterial phase). In conclusion, important differences exist among the Western and Eastern guidelines for noninvasive HCC diagnosis.

Detectability of hepatocellular carcinoma by gadoxetate disodium-enhanced hepatic MRI: tumor-by-tumor analysis in explant livers

PURPOSE

To investigate the detectability of hepatocellular carcinoma (HCC) on Gd-EOB-enhanced MR images (Gd-EOB-MRI), we performed tumor-by-tumor analysis of pathologically confirmed tumors using explants from cirrhotic patients who had undergone liver transplantation.

MATERIALS AND METHODS

We studied 11 explanted livers and classified the tumor intensity during the arterial phase (AP) and the hepatobiliary phase (HBP) as low in HBP with early enhancement (EE) in AP (A), as high in HBP with EE in AP (B), as low in HBP without EE in AP (C), as high in HBP without EE in AP (D), and as iso-intense in HBP with EE in AP (E). The diagnostic criteria for HCC were (i) pattern A and C, (ii) pattern A and E, (iii) pattern C and E, and (iv) patterns A, C, and E.

RESULTS

Of the 71 HCCs, 22 were not detected at MRI; of these, 9 were moderately differentiated and 13 were well-differentiated HCCs. The sensitivity of Gd-EOB-MRI for diagnostic criteria 1, 2, 3, and 4 was 63.4%, 52.1%, 22.5%, and 69.0%.

CONCLUSION

The maximum sensitivity of Gd-EOB-MRI for HCC was only 69.0% even when diagnostic criteria that included all previously reported HCC patterns were adopted.

Diagnosis of hepatocellular carcinoma: newer radiological tools

With the recent dramatic advances in diagnostic modalities, the diagnosis of hepatocellular carcinoma (HCC) is primarily based on imaging. Ultrasound (US) plays a crucial role in HCC surveillance. Dynamic multiphasic multidetector-row CT (MDCT) and magnetic resonance imaging (MRI) are the standard diagnostic methods for the noninvasive diagnosis of HCC, which can be made based on hemodynamic features (arterial enhancement and delayed washout). The technical development of MDCT and MRI has made possible the fast scanning with better image quality and resolution, which enables an accurate CT hemodynamic evaluation of hepatocellular tumor, as well as the application of perfusion CT and MRI in clinical practice. Perfusion CT and MRI can measure perfusion parameters of tumor quantitatively and can be used for treatment response assessment to anti-vascular agents. Besides assessing the hemodynamic or perfusion features of HCC, new advances in MRI can provide a cellular information of HCC. Liver-specific hepatobiliary contrast agents, such as gadoxetic acid, give information regarding hepatocellular function or defect of the lesion, which improves lesion detection and characterization. Diffusion-weighted imaging (DWI) of the liver provides cellular information of HCC and also has broadened its role in lesion detection, lesion characterization, and treatment response assessment to chemotherapeutic agents. In this article, we provide an overview of the state-of-the art imaging techniques of the liver and their clinical role in management of HCC.

Non-invasive diagnosis of focal liver lesions: an individualized approach

Modern cross-sectional imaging with multidetector computed tomography (MDCT) or magnetic resonance imaging (MRI) often reveals small focal liver lesions, which puts pressure on the reporting radiologist to characterize these tiny lesions. On the other hand, in patients with underlying diffuse liver disease, such as cirrhosis or severe steatosis, the detection of focal liver lesions can be quite difficult. Strategies for optimal detection and characterization of focal liver lesions should be developed according to the clinical situation, the likelihood of malignant disease and the presence of underlying diffuse liver disease. The presence or absence of a clinical history of cancer determines the algorithm for further characterization: work-up with contrast-enhanced MRI, biopsy or follow-up. In patients with chronic liver disease, recent guidelines on the detection of hepatocellular carcinoma (HCC) favour the use of multiphasic MRI or MDCT, which allows confident diagnoses of HCC >1 cm. For lesions <1 cm in chronic liver disease, follow-up is recommended. In patients with moderate to severe steatosis, contrast-enhanced MDCT has low diagnostic yield for the detection of liver lesions; contrast-enhanced MRI is far superior. This review describes successful strategies for the detection and characterization of focal liver lesions in different clinical scenarios.

Hepatocellular carcinoma in a North American population: does hepatobiliary MR imaging with Gd-EOB-DTPA improve sensitivity and confidence for diagnosis?

PURPOSE

To evaluate the value of hepatobiliary phase imaging for detection and characterization of hepatocellular carcinoma (HCC) in liver MRI with Gd-EOB-DTPA, in a North American population.

MATERIALS AND METHODS

One hundred MRI examinations performed with the intravenous injection of Gd-EOB-DTPA in patients with cirrhosis were reviewed retrospectively. Nodules were classified as HCC (n = 70), indeterminate (n = 33), or benign (n = 22). Five readers independently reviewed each examination with and without hepatobiliary phase images (HBP). Lesion conspicuity scores were compared between the two readings. Lesion detection, confidence scores, and receiver operating characteristic (ROC) analysis were compared.

RESULTS

Lesion detection was slightly improved for all lesion types with the inclusion of the HBP, and was substantially higher for small HCCs (96.0% versus 85.3%). Mean confidence scores for the diagnosis of HCC increased for HCCs overall and each size category (P < 0.001). Diagnostic performance improved with the addition of the HBP (aggregate AROC 87.7% versus 80.0%, P < 0.01), and sensitivity for characterization improved (90.9% versus 78.3%, P < 0.01) while specificity was unchanged.

CONCLUSION

Hepatobiliary phase imaging may improve small lesion detection (<1 cm) and characterization of lesions in general, in MRI of the cirrhotic liver with Gd-EOB-DTPA.

Hyperintense HCC on hepatobiliary phase images of gadoxetic acid-enhanced MRI: correlation with clinical and pathological features

PURPOSE

To retrospectively determine whether the hyperintense hepatocellular carcinomas (HCCs) seen on the hepatobiliary phase of gadoxetic acid-enhanced MR imaging (EOB-MRI) might have different histologic characteristics from usual hypointense HCCs.

MATERIALS AND METHODS

Two hundred three surgically proven HCCs from 192 patients who underwent preoperative EOB-MRI were analyzed. The demographic and histologic characteristics of hyperintense HCCs were compared with usual hypointense HCCs by using the t-test or Fisher's exact test.

RESULTS

By visual assessment, 18 (8.8%) tumors were classified as hyperintense HCCs. Patients with hyperintense HCC were significantly (p<0.05) older (60.1 vs. 55.2 years) than those with hypointense HCCs. Hyperintense HCCs showed significantly lower rate of microvascular invasion (27.8% vs. 53.5%) and significantly higher rate of peliosis (61.1% vs. 30.8%). Hyperintense HCCs were more frequently expanding type, and none showed infiltrative type or scirrhous histologic pattern.

CONCLUSIONS

Hyperintense HCCs seem to have clinical and histologic features that might be related with more favorable outcomes.

Assessment of Gd-EOB-DTPA-enhanced MRI for HCC and dysplastic nodules and comparison of detection sensitivity versus MDCT

BACKGROUND

We aimed to evaluate gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) for the detection of hepatocellular carcinomas (HCCs) and dysplastic nodules (DNs) compared with dynamic multi-detector row computed tomography (MDCT), and to discriminate between HCCs and DNs.

METHODS

Eighty-six nodules diagnosed as HCC or DNs were retrospectively investigated. Gd-EOB-DTPA-enhanced MRI and dynamic MDCT were compared with respect to their diagnostic ability for hypervascular HCCs and detection sensitivity for hypovascular tumors. The ability of hepatobiliary images of Gd-EOB-DTPA-enhanced MRI to discriminate between these nodules was assessed. We also calculated the EOB enhancement ratio of the tumors.

RESULTS

For hypervascular HCCs, the diagnostic ability of Gd-EOB-DTPA-enhanced MRI was significantly higher than that of MDCT for tumors less than 2 cm (p = 0.048). There was no difference in the detection of hypervascular HCCs between hepatobiliary phase images of Gd-EOB-DTPA-enhanced MRI (43/45: 96%) and dynamic MDCT (40/45: 89%), whereas the detection sensitivity of hypovascular tumors by Gd-EOB-DTPA-enhanced MRI was significantly higher than that by dynamic MDCT (39/41: 95% vs. 25/41: 61%, p = 0.001). EOB enhancement ratios were decreased in parallel with the degree of differentiation in DNs and HCCs, although there was no difference between DNs and hypovascular well-differentiated HCCs.

CONCLUSION

The diagnostic ability of Gd-EOB-DTPA-enhanced MRI for hypervascular HCCs less than 2 cm was significantly higher than that of MDCT. For hypovascular tumors, the detection sensitivity of hepatobiliary phase images of Gd-EOB-DTPA-enhanced MRI was significantly higher than that of dynamic Gd-EOB-DTPA-enhanced MRI and dynamic MDCT. It was difficult to distinguish between DNs and hypovascular well-differentiated HCCs based on the EOB enhancement ratio.

Hypovascular hypointense nodules on hepatobiliary phase gadoxetic acid-enhanced MR images in patients with cirrhosis: potential of DW imaging in predicting progression to hypervascular HCC

PURPOSE

To investigate the imaging features of hypovascular hypointense nodules on hepatobiliary phase gadoxetic acid-enhanced magnetic resonance (MR) images in patients with cirrhosis that may be associated with progression to hypervascular hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

The institutional review board approved this retrospective study and waived informed patient consent. This study included 135 patients with a diagnosis of hepatitis B-induced liver cirrhosis and 214 hypovascular hypointense nodules on hepatobiliary phase gadoxetic acid-enhanced MR images. MR images were analyzed with respect to nodule size, degree of hypointensity at hepatobiliary phase (four grades), presence of fat, and signal intensity on T1- and T2-weighted and diffusion-weighted (DW) images. Univariate and multivariate Cox regression analyses were used to identify variables that are associated with developing hypervascular HCC.

RESULTS

On follow-up MR images, 139 nodules (65.0%) had no evidence of HCC (mean follow-up, 522 days) (group 1), but 75 (35.0%) became hypervascular HCC (mean follow-up, 388 days) (group 2). Univariable Cox analysis revealed that the degree of hypointensity on hepatobiliary phase images (P=.044 and .001) and hyperintensity on T2-weighted and DW images (P=.001 and .0001) was significantly related to the development of hypervascular HCC. According to the multivariable Cox analysis, no other variable significantly adjusted the model once hyperintensity at initial DW imaging was already included as an associated variable, (hazard ratio, 7.44; 95% confidence interval: 4.28, 12.94; P=.0001).

CONCLUSION

Hyperintensity on DW images in hypovascular hypointense nodules on hepatobiliary phase gadoxetic acid-enhanced MR images in patients with cirrhosis is strongly associated with progression to hypervascular HCC.

Primovist, Eovist: what to expect?

Gadolinium ethoxybenzyl dimeglumine (Gd-EOB-DTPA, Primovist in Europe and Eovist in the USA) is a liver-specific magnetic resonance imaging contrast agent that has up to 50% hepatobiliary excretion in the normal liver. After intravenous injection, Gd-EOB-DTPA distributes into the vascular and extravascular spaces during the arterial, portal venous and late dynamic phases, and progressively into the hepatocytes and bile ducts during the hepatobiliary phase. The hepatocyte uptake of Gd-EOB-DTPA mainly occurs via the organic anion transporter polypeptides OATP1B1 and B3 located at the sinusoidal membrane and biliary excretion via the multidrug resistance-associated proteins MRP2 at the canalicular membrane. Because of these characteristics, Gd-EOB-DTPA behaves similarly to non-specific gadolinium chelates during the dynamic phases, and adds substantial information during the hepatobiliary phase, improving the detection and characterization of focal liver lesions and diffuse liver disease. This information is particularly relevant for the detection of metastases, and for the detection and characterization of nodular lesions in liver cirrhosis, including early hepatocellular carcinomas. Finally, GD-EOB-DTPA-enhanced magnetic resonance imaging may provide quantitative assessment regarding liver perfusion and hepatocyte function in diffuse liver diseases. The full potential of GD-EOB-DTPA-enhanced magnetic resonance imaging has to be established further. It is already clear that GD-EOB-DTPA-enhanced magnetic resonance imaging provides anatomic and functional information in the setting of focal and diffuse liver disease that is unattainable with magnetic resonance imaging enhanced with non-specific contrast agents.

Hepatocellular carcinoma: natural history, current management, and emerging tools

Hepatocellular carcinoma (HCC) is the most common primary liver tumor and represents the third-leading cause of cancer-related death in the world. The incidence of HCC continues to increase worldwide, with a unique geographic, age, and sex distribution. The most important risk factor associated with HCC is liver cirrhosis, with the majority of cases caused by chronic infection with hepatitis B (HBV) and C (HCV) viruses and alcohol abuse, although nonalcoholic fatty liver disease is emerging as an increasingly important cause. Primary prevention in the form of HBV vaccination has led to a significant decrease in HBV-related HCC, and initiation of antiviral therapy appears to reduce the incidence of HCC in patients with chronic HBV or HCV infection. Additionally, the use of ultrasonography enables the early detection of small liver tumors and forms the backbone of recommended surveillance programs for patients at high risk for the development of HCC. Cross-sectional imaging studies, including computed tomography and magnetic resonance imaging, represent further noninvasive techniques that are increasingly employed to diagnose HCC in patients with cirrhosis. The mainstay of potentially curative therapy includes surgery – either resection or liver transplantation. However, most patients are ineligible for surgery, because of either advanced disease or underlying liver dysfunction, and are managed with locoregional and/or systemic therapies. Randomized controlled trials have demonstrated a survival benefit with both local therapies, either ablation or embolization, and systemic therapy in the form of the multikinase inhibitor sorafenib. Despite this, median survival remains poor and recurrence rates significant. Further advances in our understanding of the molecular pathogenesis of HCC hold promise in improving the diagnosis and treatment of this highly lethal cancer.

Hepatobiliary MR imaging with gadolinium-based contrast agents

The advent of gadolinium-based "hepatobiliary" contrast agents offers new opportunities for diagnostic magnetic resonance imaging (MRI) and has triggered great interest for innovative imaging approaches to the liver and bile ducts. In this review article we discuss the imaging properties of the two gadolinium-based hepatobiliary contrast agents currently available in the U.S., gadobenate dimeglumine and gadoxetic acid, as well as important pharmacokinetic differences that affect their diagnostic performance. We review potential applications, protocol optimization strategies, as well as diagnostic pitfalls. A variety of illustrative case examples will be used to demonstrate the role of these agents in detection and characterization of liver lesions as well as for imaging the biliary system. Changes in MR protocols geared toward optimizing workflow and imaging quality are also discussed. It is our aim that the information provided in this article will facilitate the optimal utilization of these agents and will stimulate the reader's pursuit of new applications for future benefit.

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.

Differentiation of early hepatocellular carcinoma from benign hepatocellular nodules on gadoxetic acid-enhanced MRI

OBJECTIVE

To test new diagnostic criteria for the discrimination of early hepatocellular carcinoma (HCC) from benign hepatocellular nodules on gadoxetic acid-enhanced MRI (Gd-EOB-MRI).

METHODS

We retrospectively analysed 34 patients with 29 surgically diagnosed early HCCs and 31 surgically diagnosed benign hepatocellular nodules. Two radiologists reviewed Gd-EOB-MRI, including diffusion-weighted imaging (DWI), and the signal intensity at each sequence, presence of arterial enhancement and washout were recorded. We composed new diagnostic criteria based on the lesion size and MRI findings, and then the diagnostic performance was compared with that of conventional imaging criteria with logistic regression and a generalised estimating equation method.

RESULTS

A size cut-off value (≥1.5 cm diameter) and MRI findings of T(1) hypointensity, T(2) hyperintensity, DWI hyperintensity on both low and high b-value images (b=50 and 800 s mm(-2), respectively), arterial enhancement, late washout and hepatobiliary hypointensity were selected as the diagnostic criteria. When lesions were considered malignant if they satisfied three or more of the above criteria, the sensitivity was significantly higher than when making a diagnosis based on arterial enhancement and washout alone (58.6% vs 13.8%, respectively; p=0.0002), while the specificity was 100.0% for both criteria.

CONCLUSION

Our new diagnostic criteria on Gd-EOB-MRI may help to improve the discrimination of early HCC from benign hepatocellular nodules.

Characteristics and distinguishing features of hepatocellular adenoma and focal nodular hyperplasia on gadoxetate disodium-enhanced MRI

OBJECTIVE

The purpose of this study is to evaluate the performance of gadoxetate disodium-enhanced MRI in the characterization of focal nodular hyperplasia (FNH) and hepatocellular adenoma and to assess potential advantages of hepatocyte phase imaging in identifying features that distinguish FNH from hepatocellular adenoma.

MATERIALS AND METHODS

Gadoxetate disodium-enhanced MRI examinations of 12 patients with hepatocellular adenoma and 35 patients with FNH were retrospectively evaluated by three blinded readers. Diagnoses and confidence scores were recorded before and after disclosure of hepatocyte phase images. The data obtained were combined to create receiver operating characteristic curves, and the areas under the curves were compared. Imaging characteristics, including signal intensity, were recorded. Lesion-to-liver enhancement ratio was calculated for each contrast-enhanced phase.

RESULTS

The readers' average receiver operating characteristic area was significantly higher after disclosure of hepatocyte phase images (p=0.024). FNHs were correctly diagnosed in 74.3-97.1% of cases before and 97.1-100% of cases after the disclosure of hepatocyte phase images; hepatocellular adenoma was correctly diagnosed in 83-100% and 91.7-100% of cases (p>0.05). The presence of a central scar in FNH and fat on hepatocellular adenoma were the only morphologic features that were statistically significantly different (p<0.05). FNH had greater average contrast-enhanced signal intensity and enhancement ratio in all phases (p<0.001). A hepatocyte phase enhancement ratio of less than 0.7 was 100% specific and 91.6% sensitive for hepatocellular adenoma, with accuracy of 97.1% for these data.

CONCLUSION

Gadoxetate disodium-enhanced MRI had high accuracy in diagnosis of FNH and hepatocellular adenoma, and the hepatocyte phase improved their distinction. FNH enhances significantly more than hepatocellular adenoma. An enhancement ratio, particularly in the hepatocyte phase, can be potentially used as an additional distinguishing feature.

Using low tube voltage (80kVp) quadruple phase liver CT for the detection of hepatocellular carcinoma: two-year experience and comparison with Gd-EOB-DTPA enhanced liver MRI

PURPOSE

To validate the diagnostic performance of quadruple phase low tube voltage liver CT through the comparison with Gd-EOB-DTPA enhanced liver MRI for the detection of HCC.

MATERIALS AND METHODS

Non-obese patients (38 men, eight women) with 68 HCCs underwent quadruple-phase CT at 16 MDCT (using low tube voltage, 80kVp; moderately high tube current, 280mAs) and Gd-EOB-DTPA-enhanced 3T MRI. Three observers independently and randomly reviewed the CT and MR images on a tumor-by-tumor basis. The diagnostic accuracy of these techniques for detecting HCC was assessed using alternative free-response receiver operating characteristic analysis. Sensitivity and positive predictive values were evaluated. The mean effective doses for the low dose CT were also evaluated.

RESULTS

The areas under the ROC curves were 0.963, 0.959, and 0.941 for low dose CT and 0.981, 0.982, and 0.976 for MRI. Differences in Az of the two techniques for each observer were not statistically significant (P>.05). Differences in sensitivity and positive predictive values between the two techniques for each observer were not also statistically significant: sensitivity (86.8%, 82.4%, 85.3% for CT and 95.6%, 94.1%, 91.2% for MRI) and positive predictive values (92.2%, 90.3%, 89.2% for CT and 92.9%, 92.8%, 92.5% for MRI). Six HCCs (8.8%) in five patients were observed only on hepatobiliary phase of MRI, and all were smaller than 1.5cm. The mean effective dose for CT was approximately 10.2mSv.

CONCLUSIONS

Quadruple-phase low-dose liver CT (80kVp, 280mAs) had relatively good diagnostic performance for detecting HCC in non-obese patients. Because no significant difference was observed between low-dose CT and MRI, the use of low-dose liver CT can be justified based on its reduced radiation effects.

Clinical significance of the transitional phase at gadoxetate disodium-enhanced hepatic MRI for the diagnosis of hepatocellular carcinoma: preliminary results

OBJECTIVES

To investigate the clinical significance of the "transitional phase" at gadoxetate disodium (Gd-EOB)-enhanced magnetic resonance imaging for diagnosing hepatocellular carcinoma (HCC).

METHODS

We studied 54 patients with 70 histologically diagnosed HCC. Transitional- and hepatobiliary-phase (TP, HBP) images were acquired 3 and 20 minutes after Gd-EOB injection, respectively. Radiologists measured the size of the hepatic tumors on images and surgical specimens and qualitatively evaluated the signal intensity of the hepatic tumors during TP and HBP independently.

RESULTS

In 4 patients with portal tumor embolism who had undergone percutaneous transhepatic portal embolization and who manifested arterioportal (AP) shunts, the low-intensity area was larger during HBP than TP. Of the 70 HCCs, 4 were of high signal intensity during HBP and 2 were of slightly low intensity during TP.

CONCLUSION

Tumor extension seen during TP rather than HBP more accurately reflected histological findings in patients with HCC with portal tumor thrombi, percutaneous transhepatic portal embolization, or AP shunt.

Assessment of arterial hypervascularity of hepatocellular carcinoma: comparison of contrast-enhanced US and gadoxetate disodium-enhanced MR imaging

OBJECTIVE

To compare contrast-enhanced (CE) ultrasound with gadoxetate disodium-enhanced magnetic resonance (MR) imaging in the assessment of arterial hypervascularity of hepatocellular carcinoma (HCC) and dysplastic nodule (DN), with CT during hepatic arteriography (CTHA) as the reference standard.

METHODS

This study included 54 consecutively diagnosed patients, with 57 histologically confirmed HCCs and 3 DNs (high-grade). All patients underwent CE ultrasound, gadoxetate disodium-enhanced MR imaging and CTHA. Two trained diagnostic radiologists interpreted the CTHA images and rated the degree of intratumoral arterial vascularity by consensus using a five-point confidence scale as the reference standard. In the observer study, the degrees of vascularity on CE ultrasound and gadoxetate disodium-enhanced MR images were qualitatively analysed by four independent readers using a five-point confidence scale. Diagnostic accuracy was analysed by receiver-operating characteristic (ROC) analysis.

RESULTS

The diagnostic accuracies of the average area under the ROC curve (AUC) were significantly greater with CE ultrasound (average AUC: 0.94; 95% confidence interval [CI]: 0.88-1.00) than with gadoxetate disodium-enhanced MR imaging (average AUC 0.84, 95% CI 0.74-0.93, P = 0.0014).

CONCLUSION

Contrast-enhanced ultrasound yields a significantly higher AUC value than gadoxetate disodium-enhanced MR imaging in the assessment of arterial hypervascularity of HCC and DN.

KEY POINTS

• Arterial hypervascularity is an important feature determining treatment options in hepatocellular carcinoma. • It can be assessed by contrast-enhanced (CE) ultrasound or magnetic resonance (MR) imaging. • CE ultrasound was more accurate than Gd-EOB-DTPA MRI in assessing intratumoral vascularity. • Hypovascular hepatic nodules should be further investigated using CE ultrasound.

Ultrasonography, computed tomography and magnetic resonance imaging of hepatocellular carcinoma: toward improved treatment decisions

Detection, characterization, staging, and treatment monitoring are major roles in imaging diagnosis in liver cancers. Contrast-enhanced ultrasonography (CEUS) using microbubble contrast agents has expanded the role of US in the detection and diagnosis of liver nodules in patients at high risk of hepatocellular carcinoma (HCC). CEUS provides an accurate differentiation between benign and malignant liver nodules, which is critical for adequate management of HCC and is also useful for guidance of percutaneous local therapy of HCC and postprocedure monitoring of the therapeutic response. The technology of multidetector-row computed tomography (MDCT) has increased spatial and temporal resolutions of computed tomography (CT). It has made possible a more precise evaluation of the hemodynamics of liver tumor, and the diagnostic accuracy of dynamic MDCT has improved. Perfusion CT can measure tissue perfusion parameters quantitatively and can assess segmental hepatic function. Dynamic MDCT with high spatial and temporal resolution enables us to reconstruct 3- and 4-dimensional imaging, which is very useful for pretreatment evaluation. Dual-energy CT makes possible the differentiation of materials and tissues in images obtained based on the differences in iodine and water densities. Monochromatic images, which can be reconstructed by dual-energy CT data, provide some improvement in contrast and show a higher contrast-to-noise ratio for hypervascular HCCs. Dynamic magnetic resonance imaging with fast imaging sequence of 3-dimensional Fourier transformation T(1)-weighted gradient echo and nonspecific contrast medium can show high detection sensitivity of hypervascular HCC. However, the hepatic tissue-specific contrast medium, gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid, has become an essential contrast medium for liver imaging because of its higher diagnostic ability. It may replace CT during hepatic arteriography and during arterioportography.

Imaging features of small hepatocellular carcinomas with microvascular invasion on gadoxetic acid-enhanced MR imaging

OBJECTIVES

Detection of hepatocellular carcinomas (HCCs) before microvascular invasion (MVI) occurs is important due to the poor outcomes associated with MVI. We retrospectively investigated the imaging features of small HCCs with MVI on gadoxetic acid-enhanced MR imaging.

METHODS

Fifty patients (40 men and 10 women; mean age, 54 years) with 58 surgically proven small (2 cm or less) HCCs were evaluated by gadoxetic acid-enhanced MRI. Signal intensities on imaging sequences and the presence of the typical dynamic enhancement pattern (arterial enhancement and washout) were assessed. Fisher's exact tests were performed to evaluate the relationships between the presence of MVI, tumor size, and imaging findings.

RESULTS

None of the 12 small HCCs with diameters of 1cm or less had MVI, while 15 (33%) of the 46 small HCCs with diameters of 1.1-2.0 cm had MVI (p=0.025, Fisher's exact test). Among the small HCCs with diameters of 1.1-2.0 cm, all HCCs with MVI showed the typical dynamic pattern and hyperintensity on T2- and diffusion-weighted images. Most HCCs (54 lesions, 93%) were hypointense on hepatobiliary phase images regardless of the presence of MVI.

CONCLUSIONS

All small HCCs with MVI showed typical dynamic pattern and hyperintensity on T2-weighted and diffusion-weighted images, while atypical dynamic pattern and size of less than 1cm in diameter may suggest absence of MVI.

Magnetic resonance imaging of focal liver lesions: approach to imaging diagnosis

This article is a review of magnetic resonance imaging (MRI) of incidental focal liver lesions. This review provides an overview of liver MRI protocol, diffusion-weighted imaging, and contrast agents. Additionally, the most commonly encountered benign and malignant lesions are discussed with emphasis on imaging appearance and the diagnostic performance of MRI based on a review of the literature.

Prediction of microvascular invasion of hepatocellular carcinoma: usefulness of peritumoral hypointensity seen on gadoxetate disodium-enhanced hepatobiliary phase images

PURPOSE

To determine whether peritumoral hypointensity seen on hepatobiliary phase images of preoperative gadoxetate disodium-enhanced magnetic resonance imaging (EOB-MRI) is useful for predicting microvascular invasion of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

This study was approved by the Institutional Review Board. In all, 104 HCC masses in 104 patients who had undergone EOB-MRI and liver surgery within 1 month after EOB-MRI were evaluated. Two radiologists independently recorded the presence of a peritumoral hypointensity on hepatobiliary phase. Interobserver agreement was assessed and consensus records were used. Tumor size was measured. A chi-square test and independent t-test were used for univariate analysis. Multiple logistic regression was performed to determine factors for predicting microvascular invasion. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of peritumoral hypointensity were calculated.

RESULTS

Sixty HCCs had microvascular invasion and 44 did not. Interobserver agreement in determining peritumoral hypointensity was excellent (κ = 0.83). By univariate analysis, peritumoral hypointensity and tumor size were significant for predicting microvascular invasion of HCC. On multiple logistic regression analysis, only peritumoral hypointensity was significant in predicting microvascular invasion of HCC (P = 0.013). The sensitivity, specificity, PPV, and NPV of peritumoral hypointensity were 38.3%, 93.2%, 88.5%, and 52.6%, respectively.

CONCLUSION

Peritumoral hypointensity on the hepatobiliary phase of EOB-MRI is not sensitive but has high specificity for predicting microvascular invasion of HCC.