Hepatocellular carcinoma in liver transplantation candidates: detection with gadobenate dimeglumine-enhanced MRI. AJR Am J Roentgenol. 2008;191:529-536. [PMID: 18647927 DOI: 10.2214/ajr.07.2565]

Magnetic resonance imaging for the diagnosis of hepatocellular carcinoma in adults with chronic liver disease

BACKGROUND

Hepatocellular carcinoma occurs mostly in people with chronic liver disease and ranks sixth in terms of global incidence of cancer, and third in terms of cancer deaths. In clinical practice, magnetic resonance imaging (MRI) is used as a second-line diagnostic imaging modality to confirm the presence of focal liver lesions suspected as hepatocellular carcinoma on prior diagnostic test such as abdominal ultrasound or alpha-fetoprotein, or both, either in surveillance programmes or in clinical settings. According to current guidelines, a single contrast-enhanced imaging study (computed tomography (CT) or MRI) showing typical hallmarks of hepatocellular carcinoma in people with cirrhosis is considered valid to diagnose hepatocellular carcinoma. The detection of hepatocellular carcinoma amenable to surgical resection could improve the prognosis. However, a significant number of hepatocellular carcinomas do not show typical hallmarks on imaging modalities, and hepatocellular carcinoma may, therefore, be missed. There is no clear evidence of the benefit of surveillance programmes in terms of overall survival: the conflicting results can be a consequence of inaccurate detection, ineffective treatment, or both. Assessing the diagnostic accuracy of MRI may clarify whether the absence of benefit could be related to underdiagnosis. Furthermore, an assessment of the accuracy of MRI in people with chronic liver disease who are not included in surveillance programmes is needed for either ruling out or diagnosing hepatocellular carcinoma.

OBJECTIVES

Primary: to assess the diagnostic accuracy of MRI for the diagnosis of hepatocellular carcinoma of any size and at any stage in adults with chronic liver disease. Secondary: to assess the diagnostic accuracy of MRI for the diagnosis of resectable hepatocellular carcinoma in adults with chronic liver disease, and to identify potential sources of heterogeneity in the results.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Hepato-Biliary Group Diagnostic Test of Accuracy Studies Register, the Cochrane Library, MEDLINE, Embase, and three other databases to 9 November 2021. We manually searched articles retrieved, contacted experts, handsearched abstract books from meetings held during the last 10 years, and searched for literature in OpenGrey (9 November 2021). Further information was requested by e-mails, but no additional information was provided. No data was obtained through correspondence with investigators. We applied no language or document-type restrictions.

SELECTION CRITERIA

Studies assessing the diagnostic accuracy of MRI for the diagnosis of hepatocellular carcinoma in adults with chronic liver disease, with cross-sectional designs, using one of the acceptable reference standards, such as pathology of the explanted liver and histology of resected or biopsied focal liver lesion with at least a six-month follow-up.

DATA COLLECTION AND ANALYSIS

At least two review authors independently screened studies, extracted data, and assessed the risk of bias and applicability concerns, using the QUADAS-2 checklist. We presented the results of sensitivity and specificity, using paired forest plots, and we tabulated the results. We used a hierarchical meta-analysis model where appropriate. We presented uncertainty of the accuracy estimates using 95% confidence intervals (CIs). We double-checked all data extractions and analyses.

MAIN RESULTS

We included 34 studies, with 4841 participants. We judged all studies to be at high risk of bias in at least one domain because most studies used different reference standards, often inappropriate to exclude the presence of the target condition, and the time interval between the index test and the reference standard was rarely defined. Regarding applicability, we judged 15% (5/34) of studies to be at low concern and 85% (29/34) of studies to be at high concern mostly owing to characteristics of the participants, most of whom were on waiting lists for orthotopic liver transplantation, and due to pathology of the explanted liver being the only reference standard. MRI for hepatocellular carcinoma of any size and stage: sensitivity 84.4% (95% CI 80.1% to 87.9%) and specificity 93.8% (95% CI 90.1% to 96.1%) (34 studies, 4841 participants; low-certainty evidence). MRI for resectable hepatocellular carcinoma: sensitivity 84.3% (95% CI 77.6% to 89.3%) and specificity 92.9% (95% CI 88.3% to 95.9%) (16 studies, 2150 participants; low-certainty evidence). The observed heterogeneity in the results remains mostly unexplained. The sensitivity analyses, which included only studies with clearly prespecified positivity criteria and only studies in which the reference standard results were interpreted without knowledge of the results of the index test, showed no variation in the results.

AUTHORS' CONCLUSIONS

We found that using MRI as a second-line imaging modality to diagnose hepatocellular carcinoma of any size and stage, 16% of people with hepatocellular carcinoma would be missed, and 6% of people without hepatocellular carcinoma would be unnecessarily treated. For resectable hepatocellular carcinoma, we found that 16% of people with resectable hepatocellular carcinoma would improperly not be resected, while 7% of people without hepatocellular carcinoma would undergo inappropriate surgery. The uncertainty resulting from the high risk of bias in the included studies and concerns regarding their applicability limit our ability to confidently draw conclusions based on our results.

Thermal ablation of CT 'invisible' liver tumors using MRI fusion: a case control study

Purpose: To evaluate whether 'invisible' liver tumors on CT can be treated by stereotactic radiofrequency ablation (SRFA) using fusion of pre-ablation MRI.Methods: In this retrospective case-control study, 60 patients (14 with Hepatocellular carcinoma (HCC) and 46 with metastatic liver tumors) with CT 'invisible' lesions underwent SRFA using MRI-fusion between June 2005 and June 2018 ('fusion group'). For comparison, 60 patients who underwent SRFA without image fusion were selected using nearest neighbor propensity score matching ('control group'). Endpoints consisted of local tumor control, safety, overall and disease-free survival.Results: Major complications occurred in 6/69 ablations (8.7%) in the fusion group and in 6/89 ablations (6.7%) in the control group (p = 0.434). Primary technical efficacy rate (i.e., successful initial ablation) was 96.6% (28/29) for HCC and 97.9% (166/170) for metastatic disease in the fusion group and 100% (33/33) and 93.3% (184/194) in the control group, respectively (p = 0.468 and 0.064). Local recurrence (LR) was observed in 1/29 (3.5%) HCCs and in 6/170 metastases (4.0%) in the fusion group and 1/33 (3.0%) and 21/196 (10.7%) in the control group, respectively. The LR rate of metastasis in the control group was significantly higher (p = 0.007), although differences in OS and DFS did not reach statistical significance.Conclusions: Image fusion using pre-procedural MRI allows for ablation of CT-'invisible' liver tumors that are otherwise untreatable. Moreover, local oncological control was higher in metastatic liver tumors versus matched controls which suggests it could be useful tool for all stereotactic radiofrequency ablation procedures.

Differentiation of Small Hepatocellular Carcinoma From Dysplastic Nodules in Cirrhotic Liver: Texture Analysis Based on MRI Improved Performance in Comparison Over Gadoxetic Acid-Enhanced MR and Diffusion-Weighted Imaging

Background: Accurate characterization of small (3 cm) hepatocellular carcinoma (sHCC) and dysplastic nodules (DNs) in cirrhotic liver is challenging. We aimed to investigate whether texture analysis (TA) based on T2-weighted images (T2WI) is superior to qualitative diagnosis using gadoxetic acid-enhanced MR imaging (Gd-EOB-MRI) and diffusion-weighted imaging (DWI) for distinguishing sHCC from DNs in cirrhosis.

Materials and methods: Sixty-eight patients with 73 liver nodules (46 HCCs, 27 DNs) pathologically confirmed by operation were included. For imaging diagnosis, three sets of images were reviewed by two experienced radiologists in consensus: a Gd-EOB-MRI set, a DWI set, and a combined set (combination of Gd-EOB-MRI and DWI). For TA, 279 texture features resulting from T2WI were extracted for each lesion. The performance of each approach was evaluated by a receiver operating characteristic analysis. The area under the receiver operating characteristic curve (A_z), sensitivity, specificity, and accuracy were determined.

Results: The performance of TA (A_z = 0.96) was significantly higher than that of imaging diagnosis using Gd-EOB-MRI set (A_z = 0.86) or DWI set (A_z = 0.80) alone in differentiation of sHCC from DNs (P = 0.008 and 0.025, respectively). The combination of Gd-EOB-MRI and DWI showed a greater sensitivity (95.6%) but reduced specificity (66.7%). The specificity of TA (92.6%) was significantly higher than that of the combined set (P < 0.001), but no significant difference was observed in sensitivity (97.8 vs. 95.6%, P = 0.559).

Conclusion: TA-based T2WI showed a better classification performance than that of qualitative diagnosis using Gd-EOB-MRI and DW imaging in differentiation of sHCCs from DNs in cirrhotic liver. TA-based MRI may become a potential imaging biomarker for the early differentiation HCCs from DNs in cirrhosis.

Hepatocellular carcinoma detection in liver cirrhosis: diagnostic performance of contrast-enhanced CT vs. MRI with extracellular contrast vs. gadoxetic acid

OBJECTIVES

To evaluate the diagnostic performance of contrast-enhanced CT vs. MRI with extracellular contrast agents (EC-MRI) vs. MRI with gadoxetic acid (EOB-MRI) for HCC detection in patients with liver cirrhosis using liver explant as the reference. The additional value of hepatobiliary phase (HBP) post Gadoxetic acid was also assessed.

METHODS

Two-hundred seventy-seven consecutive patients who underwent liver transplantation over a 9 year period and imaging within 90 days of were retrospectively included. Imaging consisted in CT (n = 100), EC-MRI (n = 77) and EOB-MRI (n = 100), the latter subdivided into dynamic EOB-MRI and full EOB-MRI (dynamic+HBP). Three radiologists retrospectively categorized lesions ≥ 1 cm using the LI-RADSv2017 algorithm. Dynamic EOB-MRI was re-evaluated with the addition of HBP. Results were correlated with explant pathology.

RESULTS

Pathology demonstrated 265 HCCs (mean size 2.1 ± 1.4 cm) in 177 patients. Per-patient sensitivities were 86.3% for CT, 89.5% for EC-MRI, 92.8% for dynamic EOB-MRI and 95.2% for full EOB-MRI (pooled reader data), with a significant difference between CT and dynamic/full EOB-MRI (p = 0.032/0.002), and between EC-MRI and full EOB-MRI (p = 0.047). Per-lesion sensitivities for CT, EC-MRI, dynamic EOB-MRI and full EOB-MRI were 59.5%,78.5%,69.7% and 76.8%, respectively, with a significant difference between MRI groups and CT (p-range:0.001-0.04), and no difference between EC-MRI and dynamic EOB-MRI (p = 0.949). For HCCs 1-1.9 cm, sensitivities were 34.4%, 64.6%, 57.3% and 67.3%, respectively, with all MRI groups significantly superior to CT (p ≤ 0.01) and full EOB-MRI superior to dynamic EOB-MRI (p = 0.002).

CONCLUSIONS

EOB-MRI outperforms CT and EC-MRI for per-patient HCC detection sensitivity, and is equivalent to EC-MRI for per-lesion sensitivity. MRI methods outperform CT for detection of HCCs 1-1.9 cm.

KEY POINTS

• MRI is superior to CT for HCC detection in patients with liver cirrhosis. • EOB-MRI outperforms CT and MRI using extracellular contrast agents (EC-MRI) for per-patient HCC detection sensitivity, and is equivalent to EC-MRI for per-lesion sensitivity. • The addition of hepatobiliary phase images improves HCC detection when using gadoxetic acid.

New hallmark of hepatocellular carcinoma, early hepatocellular carcinoma and high-grade dysplastic nodules on Gd-EOB-DTPA MRI in patients with cirrhosis: a new diagnostic algorithm

OBJECTIVE

Many improvements have been made in diagnosing hepatocellular carcinoma (HCC), but the radiological hallmarks of HCC have remained the same for many years. We prospectively evaluated the imaging criteria of HCC, early HCC and high-grade dysplastic nodules (HGDNs) in patients under surveillance for chronic liver disease, using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) MRI and diffusion-weighted imaging.

DESIGN

Our study population included 420 nodules >1 cm in 228 patients. The MRI findings of each nodule were collected in all sequences/phases. The diagnosis of HCC was made according to the American Association for the Study of Liver Diseases (AASLD) criteria; all atypical nodules were diagnosed using histology.

RESULTS

A classification and regression tree was developed using three MRI findings which were independently significant correlated variables for early HCC/HCC, and the best sequence of their application in a new diagnostic algorithm (hepatobiliary hypointensity, arterial hyperintensity and diffusion restriction) was suggested. This algorithm demonstrated, both in the entire study population and for nodules ≤2 cm, higher sensitivity (96% [95% CI 93.5% to 97.6%] and 96.6% [95% CI 93.9% to 98.5%], P<0.001, respectively) and slightly lower specificity (91.8% [95% CI 88.6% to 94.1%], P=0.063, and 92.7% [95% CI 88.9% to 95.4%], P=0.125, respectively) than those of the AASLD criteria. Our new diagnostic algorithm also showed a very high sensitivity (94.7%; 95% CI 92% to 96.6%) and specificity (99.3%; 95% CI 97.7% to 99.8%) in classifying HGDN.

CONCLUSION

Our new diagnostic algorithm demonstrated significantly higher sensitivity and comparable specificity than those of the AASLD imaging criteria for HCC in patients with cirrhosis evaluated using Gd-EOB-DTPA MRI, even for lesions ≤2 cm. Moreover, this diagnostic algorithm allowed evaluating other lesions which could arise in a cirrhotic liver, such as early HCC and HGDN.

Comparison of hepatic MDCT, MRI, and DSA to explant pathology for the detection and treatment planning of hepatocellular carcinoma

Background/Aims

The diagnosis and treatment plan for hepatocellular carcinoma (HCC) can be made from radiologic imaging. However, lesion detection may vary depending on the imaging modality. This study aims to evaluate the sensitivities of hepatic multidetector computed tomography (MDCT), magnetic resonance imaging (MRI), and digital subtraction angiography (DSA) in the detection of HCC and the consequent management impact on potential liver transplant patients.

Methods

One hundred and sixteen HCC lesions were analyzed in 41 patients who received an orthotopic liver transplant (OLT). All of the patients underwent pretransplantation hepatic DSA, MDCT, and/or MRI. The imaging results were independently reviewed retrospectively in a blinded fashion by two interventional and two abdominal radiologists. The liver explant pathology was used as the gold standard for assessing each imaging modality.

Results

The sensitivity for overall HCC detection was higher for cross-sectional imaging using MRI (51.5%, 95% confidence interval [CI]=36.2-58.4%) and MDCT (49.8%, 95% CI=43.7-55.9%) than for DSA (41.7%, 95% CI=36.2-47.3%) (P=0.05). The difference in false-positive rate was not statistically significant between MRI (22%), MDCT (29%), and DSA (29%) (P=0.67). The sensitivity was significantly higher for detecting right lobe lesions than left lobe lesions for all modalities (MRI: 56.1% vs. 43.1%, MDCT: 55.0% vs. 42.0%, and DSA: 46.9% vs. 33.9%; all P<0.01). The sensitivities of the three imaging modalities were also higher for lesions ≥2 cm vs. <2 cm (MRI: 73.4% vs. 32.7%, MDCT: 66.9% vs. 33.8%, and DSA: 62.2% vs. 24.1%; all P<0.01). The interobserver correlation was rated as very good to excellent.

Conclusion

The sensitivity for detecting HCC is higher for MRI and MDCT than for DSA, and so cross-sectional imaging modalities should be used to evaluate OLT candidacy.

Incorporating the hepatobiliary phase of gadobenate dimeglumine-enhanced MRI in the diagnosis of hepatocellular carcinoma: increasing the sensitivity without compromising specificity

BACKGROUND

Diagnosis of hepatocellular carcinoma (HCC) is centered on wash-in of contrast during the arterial phase followed by washout during the portal or delayed venous phase. Nodules showing hypointensity on the hepatobiliary phase are also likely to represent HCC, however, the role of this phase is not yet established.

PURPOSE

To investigate the role of the hepatobiliary phase on Gadobenate dimeglumine (Gd-BOPTA) magnetic resonance imaging (MRI) in characterizing HCCs lacking the typical arterial enhancement and venous washout.

MATERIAL AND METHODS

Ninety-seven cirrhotic patients (78 men, 19 women; mean age, 58.5 years) who underwent liver transplantation (2004-2012) and Gd-BOPTA enhanced MRI within 3 months of surgery were retrospectively reviewed. A nodule-by-nodule analysis was performed, followed by liver explant correlation. Statistical analysis was then performed by a biostatistician using commercially available software.

RESULTS

A total of 193 HCCs were found in 97 liver explants, of which 24.9% (48/193) were not detectable on imaging. The 145 HCCs seen on imaging showed the typical wash-in/washout pattern (Pattern A) in 46.9% (68/145), arterial enhancement without washout (Pattern B) in 37.9% (55/145), and hypovascularity on arterial and venous sequences (Pattern C) in 15.2% (22/145). Pattern A was exclusive to HCC. Twenty-three of the 55 HCCs showing Pattern B were also hypointense on the hepatobiliary phase (Pattern B1). Combining Pattern B1 with Pattern A raises the sensitivity of HCC characterization from 46.9% to 62.8% (P = 0.007), with no significant compromise on specificity.

CONCLUSION

When coupled with Pattern A, Pattern B1 augments sensitivity of HCC characterization with no significant compromise on the specificity.

Diagnostic criteria for hepatocellular carcinoma ⩽3 cm with hepatocyte-specific contrast-enhanced magnetic resonance imaging

BACKGROUND & AIMS

Current diagnostic imaging criteria for hepatocellular carcinoma (HCC) are dedicated to imaging with nonspecific extracellular contrast agents. This study aimed to evaluate diagnostic criteria for HCC ⩽3 cm on magnetic resonance imaging (MRI) with a hepatocyte-specific contrast agent through an inception cohort study.

METHODS

Of 291 patients with chronic liver disease and new nodules of 1-3 cm in diameter at surveillance ultrasonography, 295 solid nodules (194 HCCs, 98 benign nodules, and three other malignancies) in 198 patients with a confirmed final diagnosis or ⩾24 months follow-up were evaluated on gadoxetic acid-enhanced MRI. Through univariate and multivariate logistic regression analyses, various diagnostic criteria were developed by combining significant MRI findings for diagnosing HCC. The diagnostic performance of each criterion was compared with that of the European Association for the Study of the Liver (EASL) criteria.

RESULTS

Four MRI findings (arterial-phase hyperintensity, transitional-phase hypointensity, hepatobiliary-phase hypointensity, and rim enhancement) were independently significant for diagnosis of HCC ⩽3 cm. For whole nodules, EASL criteria showed the best performance for diagnosing HCC (sensitivity, 83.5%; specificity, 81.2%). For nodules ⩽2 cm in diameter, a new criterion (arterial-phase hyperintensity and hepatobiliary-phase hypointensity) showed a significantly higher sensitivity than that of the EASL criteria (83.0% vs. 74.5%, p=0.008), without a significantly different specificity (76.7% vs. 81.1%, p=0.125).

CONCLUSIONS

EASL criteria exhibit the best diagnostic performance for HCC ⩽3 cm on hepatocyte-specific contrast-enhanced MRI. A newly identified criterion (arterial-phase hyperintensity and hepatobiliary-phase hypointensity) may increase the diagnostic sensitivity of small (⩽2 cm) HCC.

Focal lesions in cirrhotic liver: what else beyond hepatocellular carcinoma?

Detection and characterization of focal lesions in the cirrhotic liver may pose a diagnostic dilemma. Several benign and malignant lesions may be found in a cirrhotic liver along with hepatocellular carcinoma (HCC), and may exhibit typical or atypical imaging features. In this pictorial essay, we illustrate computed tomography and magnetic resonance imaging findings of lesions such as simple bile duct cysts, hemangioma, focal nodular hyperplasia-like nodules, peribiliary cysts, intrahepatic cholangiocarcinoma, lymphoma, and metastases, all of which occur in cirrhotic livers with varying prevalences. Pseudolesions, such as perfusion anomalies, focal confluent fibrosis, and segmental hyperplasia, will also be discussed. Imaging characterization of non-HCC lesions in cirrhosis is important in formulating an accurate diagnosis and triaging the patient towards the most appropriate management.

Adherence to diagnostic guidelines of hepatocellular carcinoma: 12-year experience in a veterans affairs medical center

BACKGROUND

Noninvasive diagnostic criteria for cirrhotic hepatocellular carcinoma (HCC) were first established in 2001 by the European Association for the Study of the Liver.

OBJECTIVES

The aim of this study was to evaluate adherence to the HCC diagnostic algorithm over time and identify factors associated with nonadherence.

METHODS

Between 2001 and 2013, 224 consecutive cirrhotic HCC cases were retrospectively reviewed. Nonadherent biopsy (NAB) was defined as cases diagnosed either by biopsy despite meeting noninvasive criteria for HCC or by biopsy in place of an optional second imaging modality. Nonadherent nonbiopsy (NANB) was defined as cases diagnosed without performing biopsy when noninvasive criteria were not met. Factors associated with nonadherence were identified using multivariate analysis.

RESULTS

Nonadherence rate decreased from 52 to 30% over the study period (P = 0.003). Among all patients, there were 34% NAB and 13% NANB cases. Compared with the adherence group, both NAB and NANB groups were likely to undergo only computed tomography scanning [odds ratio (OR) 3.08, 95% confidence interval (CI) 1.71-5.66 and OR 3.18, 95% CI 1.28-8.27, respectively] and were less likely to undergo MRI (OR 0.29, 95% CI 0.16-0.53 and OR 0.26, 95% CI 0.10-0.66, respectively). In addition, the NAB group was less likely to be presented in a multidisciplinary tumor conference (OR 0.12, 95% CI 0.02-0.61).

CONCLUSION

This is the first study to report adherence to HCC diagnostic guidelines over time in a veteran hospital. Despite overall improvement, nonadherence at the present time is still high (∼ 30%). Underutilization of MRI and the multidisciplinary tumor conference is associated with nonadherence, representing a potential area for improvement.

Magnetic resonance imaging of the cirrhotic liver: An update

Noninvasive imaging has become the standard for hepatocellular carcinoma (HCC) diagnosis in cirrhotic livers. In this review paper, we go over the basics of MR imaging in cirrhotic livers and describe the imaging appearance of a spectrum of hepatic nodules marking the progression from regenerative nodules to low- and high-grade dysplastic nodules, and ultimately to HCCs. We detail and illustrate the typical imaging appearances of different types of HCC including focal, multi-focal, massive, diffuse/infiltrative, and intra-hepatic metastases; with emphasis on the diagnostic value of MR in imaging these lesions. We also shed some light on liver imaging reporting and data system, and the role of different magnetic resonance imaging (MRI) contrast agents and future MRI techniques including the use of advanced MR pulse sequences and utilization of hepatocyte-specific MRI contrast agents, and how they might contribute to improving the diagnostic performance of MRI in early stage HCC diagnosis.

Hepatocellular carcinoma: diagnostic performance of multidetector CT and MR imaging-a systematic review and meta-analysis

PURPOSE

To perform a systematic review and meta-analysis of the diagnostic performance of computed tomography (CT) and magnetic resonance (MR) imaging as noninvasive modalities for evaluating hepatocellular carcinoma (HCC) in patients with chronic liver disease.

MATERIALS AND METHODS

A search of the MEDLINE, EMBASE, and Cochrane Library databases was performed to identify studies providing per-patient or per-lesion diagnostic accuracies of multidetector CT and MR imaging for HCCs in patients with chronic liver disease. Studies published from January 2000 to December 2012 that used a reference standard based on histopathologic findings and/or findings at follow-up were included. Summary estimates of diagnostic accuracy were obtained by using a random-effects model with further exploration with meta-regression and subgroup analyses.

RESULTS

Forty studies (six on multidetector CT, 22 on MR imaging, and 12 on both CT and MR imaging) were included. The studies evaluated a total of 1135 patients with multidetector CT and 2489 patients with MR imaging. The overall per-patient sensitivity of MR imaging was 88% (95% confidence interval [CI]: 83%, 92%), with a specificity of 94% (95% CI: 85%, 98%). The overall per-lesion sensitivity of MR imaging was higher than that of multidetector CT when the paired data of the 11 available studies were pooled (80% vs 68%, P = .0023). Gadoxetic acid-enhanced MR imaging showed significantly higher per-lesion sensitivity than MR imaging performed with other contrast agents (87% vs 74%, P = .03). Per-lesion sensitivity was significantly lower for HCCs smaller than 1 cm than that for HCCs 1 cm or larger (P < .001 for CT, P = .02 for MR imaging) and for those in explanted livers (P = .04 for CT, P < .001 for MR imaging).

CONCLUSION

MR imaging showed higher per-lesion sensitivity than multidetector CT and should be the preferred imaging modality for the diagnosis of HCCs in patients with chronic liver disease.

Evaluating the validity of model for end-stage liver disease exception points for hepatocellular carcinoma patients with multiple nodules <2 cm

Liver transplant allocation policy does not give model for end-stage liver disease (MELD) exception points for patients with a single hepatocellular carcinoma (HCC) <2 cm in size, but does give points to patients with multiple small nodules. Because standard-of-care imaging for HCC struggles to differentiate HCC from other nodules, it is possible that a subset of patients receiving liver transplant for multiple nodules <2 cm in size does not have HCC. We evaluate risk of post-transplant HCC recurrence and wait-list dropout for patients with multiple small nodules using competing risks regression based on the Fine and Gray model. We identified 5002 adult HCC patients in the OPTN/UNOS dataset diagnosed and transplanted between January 2006 and September 2010. Compared to patients with >1 tumor <2 cm, risk of developing recurrence was significantly higher in patients with one or more tumors with only one tumor ≥2 cm (SHR 1.63, p = 0.009), as well as in patients with 2-3 tumors ≥2 cm (SHR 1.84, p = 0.02). Dropout risk was not significantly different among size categories. HCC recurrence risk was significantly lower in patients with multiple nodules <2 cm in size than in those with larger tumors, supporting the possibility that some patients received unnecessary transplants. The priority given to these patients must be re-examined.

Pretransplant diagnosis of hepatocellular carcinoma by gadoxetic acid-enhanced and diffusion-weighted magnetic resonance imaging

We sought to evaluate the diagnostic performance of gadoxetic acid-enhanced magnetic resonance imaging (MRI) with and without additional diffusion-weighted imaging (DWI) in the detection of hepatocellular carcinoma (HCC) in pretransplant patients. We included 63 liver transplant patients (54 men and 9 women; mean age = 52 years) who had undergone gadoxetic acid-enhanced MRI with DWI at 3.0 T within 90 days before transplantation. Two image sets were reviewed for HCC in 2 separate sessions by 2 independent observers: the gadoxetic acid set and the combined set (gadoxetic acid plus DWI). The sensitivity, specificity, positive predictive value, and negative predictive value were calculated for each image set. In all, 113 HCCs (size range = 0.5-7.8 cm, mean = 2.0 ± 1.3 cm) were identified in the 52 liver explants. The per-lesion sensitivity of the combined set (78.8% for both observers) was higher than the sensitivity of the gadoxetic acid set [71.7% (P = 0.02) and 72.6% (P = 0.03) for the 2 observers], with the highest trend for Child-Pugh class A (94.4% and 97.2% for gadoxetic acid and 97.2% for combined), which was followed by class B (73.2% for gadoxetic acid and 82.9% for combined) and then class C (47.2% for gadoxetic acid and 55.6% for combined, P = 0.01). The per-patient negative predictive value of the combined set was higher than that of the gadoxetic acid set for both observers (P = 0.046). There was no difference in specificity between the 2 image sets (P > 0.05). The addition of DWI to gadoxetic acid-enhanced MRI resulted in significantly higher sensitivity to detect HCC. However, the sensitivity decreased with increasing cirrhosis severity for both imaging types.

Diagnostic performance of gadoxetic acid-enhanced liver MR imaging in the detection of HCCs and allocation of transplant recipients on the basis of the Milan criteria and UNOS guidelines: correlation with histopathologic findings

PURPOSE

To determine whether hepatobiliary phase ( HBP hepatobiliary phase ) imaging can improve the diagnostic performance of gadoxetic acid-enhanced liver magnetic resonance (MR) imaging in the detection of hepatocellular carcinomas ( HCC hepatocellular carcinoma s) and to investigate the accuracy of gadoxetic acid-enhanced MR imaging in the allocation of transplant recipients on the basis of the Milan criteria and United Network for Organ Sharing ( UNOS United Network for Organ Sharing ) guidelines.

MATERIALS AND METHODS

This retrospective study had institutional review board approval; the requirement for informed consent was waived. Between June 2008 and June 2011, 63 patients who underwent liver transplantation (LT) were included. All patients underwent a gadoxetic acid-enhanced 3.0-T MR imaging examination of the liver that included HBP hepatobiliary phase images obtained 20 minutes after contrast material administration. Two abdominal radiologists independently assessed two MR imaging data sets to detect HCC hepatocellular carcinoma s: Set 1 included unenhanced and gadoxetic acid-enhanced dynamic images, and set 2 also included HBP hepatobiliary phase images. Patients were allocated into three groups: Those who did not meet the Milan criteria, those who did meet the Milan criteria with additional priority according to UNOS United Network for Organ Sharing guidelines, and those who did meet the Milan criteria without additional priority. Diagnostic performance of each data set in depicting HCC hepatocellular carcinoma s was compared by using jackknife alternative free-response receiver operating characteristics ( JAFROC jackknife alternative free-response receiver operating characteristic s). Sensitivity and accuracy of patient allocation were compared by using generalized estimating equations.

RESULTS

Sixty-three HCC hepatocellular carcinoma s were found in 36 of 63 patients. Eight patients were classified as not meeting Milan criteria, 12 as meeting Milan criteria with additional priority, and 43 as meeting Milan criteria without additional priority. For the detection of HCC hepatocellular carcinoma s, reader-averaged figures of merit estimated with JAFROC jackknife alternative free-response receiver operating characteristic s were 0.761 for set 1 and 0.791 for set 2 (P < .001). Addition of HBP hepatobiliary phase images significantly improved sensitivity for the detection of HCC hepatocellular carcinoma s, particularly 1-2-cm HCC hepatocellular carcinoma s (six [20.7%] vs 13 [44.8%] of 29 [P = .008] for reader 1 and eight [27.6%] vs 12 [41.4%] of 29 [P = .041] for reader 2). Accuracy of patient allocation was 88.9% for set 1 and 92.1% for set 2 (P = .151).

CONCLUSION

Addition of HBP hepatobiliary phase images can significantly improve the diagnostic performance of gadoxetic acid-enhanced liver MR imaging in the detection of 1-2-cm HCC hepatocellular carcinoma s in liver transplantation candidates. In addition, gadoxetic acid-enhanced MR imaging showed 92.1% accuracy in patient allocation on the basis of the Milan criteria and UNOS United Network for Organ Sharing guidelines.

The role of hepatocyte-specific contrast agents in hepatobiliary magnetic resonance imaging

Hepatocyte-specific contrast agents have been made available in the last 15 years for magnetic resonance imaging of the liver. These agents are differentially taken up by functioning hepatocytes and excreted in the biliary system. They can help distinguish focal liver lesions of hepatocellular origin from lesions of nonhepatocellular origin, and can also be used in the evaluation of the biliary tree. The purpose of this review is to summarize the different types of hepatocyte-specific contrast agents presently available, their use in the characterization of focal liver lesions, their role in the evaluation of biliary pathology, and their potential future applications.

Hepatocellular carcinoma likelihood on MRI exams: evaluation of a standardized categorization system

PURPOSE

Evaluate the reliability and validity of a standardized reporting system designed to improve communication between the clinician and radiologist regarding likelihood of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

The system assigns liver lesions into 1 of 5 categories of estimated likelihood of HCC: 1, <5%; 2, 5%-20%; 3, 21%-70%; 4, 71%-95%; 5, >95%. Six American Board of Radiology-certified radiologists reviewed 100 abdominal MRI studies (performed between September 2009 and June 2010 for HCC surveillance) blinded to the official reports and clinical information. Each reader recorded the highest category (1-5) assigned to any lesion per study. Reliability between readers was calculated by the Shrout-Fliess random sets intraclass correlation (ICC). To examine validity, original pretransplant reports from January 2009 to December 2010 were compared to pathology reports on liver explants. Sensitivities, specificities, predictive values, and receiver operating characteristic (ROC) curves were then produced.

RESULTS

The ICC for retrospective readings was 0.80, indicating very good reliability. Of 45 pathologically proven cases, 16 category 1 or 2 cases were all free of HCC (negative predictive value 100%). Five of nine category 3 cases contained HCC. Six of eight category 4 cases contained HCC (PPV 75%). All 12 category 5 cases contained HCC (positive predictive value 100%). The area underneath the ROC curve was 0.949. If categories 1 and 2 are considered negative and categories 3-5 considered positive, this achieves 100% sensitivity with 73% specificity.

CONCLUSION

This standardized system for reporting likelihood of HCC, which is a forerunner of the recently introduced Liver Imaging Reporting and Data System, produces strong reliability and validity, while aiming to improve the clarity of clinical magnetic resonance imaging reports.

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.

Imaging of hepatocellular carcinoma: diagnosis, staging and treatment monitoring

Hepatocellular carcinoma (HCC) is the most common primary liver cancer. Imaging is important for establishing a diagnosis of HCC. Several imaging modalities including ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET) and angiography are used in evaluating patients with chronic liver disease and suspected HCC. CT, MRI and contrast-enhanced US have replaced biopsy for diagnosis of HCC. Dynamic multiphase contrast-enhanced CT or MRI is the current standard for imaging diagnosis of HCC. Functional imaging techniques such as perfusion CT and diffusion-weighted MRI provide additional information about tumor angiogenesis that may be useful for treatment. Techniques evaluating tissue mechanical properties such as magnetic resonance elastography, and acoustic radiation force impulse imaging are being explored for characterizing liver lesions. The role of PET in the evaluation of HCC is evolving with promise seen especially with the use of a hepatocyte-specific PET tracer. Imaging is also critical for assessment of treatment response and detection of recurrence following locoregional treatment. Knowledge of the post-treatment appearance of HCC is essential for correct interpretation. This review article provides an overview of the role of imaging in the diagnosis, staging and post-treatment follow-up of HCC.

Retrospective audit to determine the diagnostic accuracy of Primovist-enhanced MRI in the detection of hepatocellular carcinoma in cirrhosis with explant histopathology correlation

INTRODUCTION

This study aims to determine the diagnostic accuracy of Primovist-enhanced MRI in the detection of hepatocellular carcinoma (HCC) in cirrhosis, using liver explant histopathology correlation.

METHODS

Thirty patients underwent a Primovist-enhanced MRI prior to liver transplantation for cirrhosis at the Princess Alexandra Hospital from 2006 to June 2012. Pre-contrast T1, T2 and post-Primovist arterial, portal venous and delayed hepatobiliary phase sequences were routinely obtained. A retrospective audit of MRI reports determined whether HCCs was identified on pre-transplantation imaging. Results were correlated to the explant liver histopathology. Specificity and sensitivity of Primovist in HCC identification in cirrhosis was determined.

RESULTS

The time interval between preoperative MRI and transplantation ranged from the day of transplantation to 112 weeks pre-transplantation. Thirty-nine HCCs were identified histologically in explants. Fifteen HCCs were identified on pre-transplant MRI in 11 patients, ranging from 11 to 43 mm, all confirmed on histopathology. Fourteen MRI studies identified no lesion, concordant on histology. Twenty-four either well or moderately differentiated HCCs were identified on histopathology, all of which were less than 17 mm, were not depicted on MRI. No poorly differentiated HCCs were present in the explants. Two regenerative nodules were correctly identified on MRI. This correlated to a sensitivity of 42.5%, specificity of 100% and a positive predictive value of 100% and negative predictive value of 39.5%.

CONCLUSION

Primovist-enhanced MRI is very accurate in the identification of HCC in cirrhosis, especially if the tumour is greater than 17 mm and undifferentiated. However, sensitivity is reduced for well- and moderately differentiated HCC less than 17 mm.

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.

Use of magnetic resonance imaging contrast agents in the liver and biliary tract

This article presents an overview of liver and biliary contrast agents including their mechanisms of action, dosage and elimination, current clinical indications, and potential future uses.

Contrast agents as a biological marker in magnetic resonance imaging of the liver: conventional and new approaches

Liver imaging is an important clinical area in everyday practice. The clinical meaning of different lesion types in the liver can be quite different. Therefore, the result of imaging studies of the liver can change therapeutic concepts fundamentally. Contrast agents are used in the majority of MR examinations of the liver parenchyma-despite the already good soft-tissue contrast in plain MRI. This can be explained by the advantages in lesion detection and characterization of contrast-enhanced MRI of the liver. Beyond the qualitative evaluation of contrast-enhanced liver MR examinations, quantification of parameters will be the demand of the future. This can be achieved by perfusion MRI, also called dynamic contrast-enhanced MRI (DCE-MRI) of the liver. Its basic principles and different clinical applications will be discussed in this article. Definite cut-off values to determine disease or therapeutic response will help to increase the objectivity and reliability of liver MRI in future. This is especially important in the oncological setting, where modern therapies cannot be assessed based on changes in size only.

Liver transplantation for unresectable hepatocellular carcinoma in normal livers

BACKGROUND & AIMS

The role of liver transplantation in the treatment of hepatocellular carcinoma in livers without fibrosis/cirrhosis (NC-HCC) is unclear. We aimed to determine selection criteria for liver transplantation in patients with NC-HCC.

METHODS

Using the European Liver Transplant Registry, we identified 105 patients who underwent liver transplantation for unresectable NC-HCC. Detailed information about patient, tumor characteristics, and survival was obtained from the transplant centers. Variables associated with survival were identified using univariate and multivariate statistical analyses.

RESULTS

Liver transplantation was primary treatment in 62 patients and rescue therapy for intrahepatic recurrences after liver resection in 43. Median number of tumors was 3 (range 1-7) and median tumor size 8 cm (range 0.5-30). One- and 5-year overall and tumor-free survival rates were 84% and 49% and 76% and 43%, respectively. Macrovascular invasion (HR 2.55, 95% CI 1.34 to 4.86), lymph node involvement (HR 2.60, 95% CI 1.28 to 5.28), and time interval between liver resection and transplantation < 12 months (HR 2.12, 95% CI 0.96 to 4.67) were independently associated with survival. Five-year survival in patients without macrovascular invasion or lymph node involvement was 59% (95% CI 47-70%). Tumor size was not associated with survival.

CONCLUSIONS

This is the largest reported series of patients transplanted for NC-HCC. Selection of patients without macrovascular invasion or lymph node involvement, or patients ≥ 12months after previous liver resection, can result in 5-year survival rates of 59%. In contrast to HCC in cirrhosis, tumor size is not a predictor of post-transplant survival in NC-HCC.

Which is the best MRI marker of malignancy for atypical cirrhotic nodules: hypointensity in hepatobiliary phase alone or combined with other features? Classification after Gd-EOB-DTPA administration

PURPOSE

To investigate whether the malignancy of atypical nodules in cirrhosis can be identified at gadoxetic-acid-disodium(Gd-EOB-DTPA)-MRI by their hypointensity in the hepatobiliary(HB)-phase alone or combined with any other MR imaging features.

MATERIALS AND METHODS

One hundred eleven atypical nodules detected in 77 consecutive Gd-EOB-DTPA-MRIs were divided, based on arterial-phase behavior, into: Class I, isovascular (n = 82), and Class II, hypervascular without portal/delayed washout (n = 29). The two classes were further grouped based on HB-phase intensity (A/B/C hypo/iso/hyperintensity). Portal/venous/equilibrium-phase behavior and T2w features were also collected. Histology was the gold standard. Per-nodule sensitivity, specificity, negative and positive predictive values (NPV/PPV), and diagnostic accuracy were calculated for HB-phase hypointensity alone, and combined with vascular patterns and T2w hyperintensity.

RESULTS

Histology detected 60 benign and 51 malignant/premalignant nodules [10 overt hepatocellular carcinomas (HCCs) and 41 high-grade dysplastic nodules (HGDN)/early HCC]. Class IA contained 31 (94%) malignancies, IB one (3%), and IC only benign lesions. Class IIA had 100% malignancies, IIB three (37.5%) and IIC only two (28.5%). HB-phase hypointensity alone (Classes I-IIA) had 88% sensitivity, 91% NPV, and 93% diagnostic accuracy, superior (P < 0.05, P < 0.006, and P < 0.05, respectively) to any other MR imaging feature alone or combined.

CONCLUSION

In atypical cirrhotic nodules, HB-phase hypointensity by itself is the strongest marker of malignancy.

MRI of Focal Liver Lesions

Magnetic resonance imaging, MRI has more advantages than ultrasound, computed tomography, CT, positron emission tomography, PET, or any other imaging modality in diagnosing focal hepatic masses. With a combination of basic T1 and T2 weighted sequences, diffusion weighted imaging, DWI, and hepatobiliary gadolinium contrast agents, that is gadobenate dimeglumine (Gd-BOPTA) and gadoxetic acid (Gd-EOB), most liver lesions can be adequately diagnosed. Benign lesions, as cyst, hemangioma, focal nodular hyperplasia, FNH or adenoma, can be distinguished from malignant lesions. In a non-cirrhotic liver, the most common malignant lesions are metastases which may be hypovascular or hypervascular. In the cirrhotic liver hepatocellular carcinoma, HCC, is of considerable importance. Besides, intrahepatic cholangiocarcinoma and other less common malignancies has to be assessed. In this review, the techniques and typical MRI features are presented as well as the new algorithm issued by American Association for the Study of the Liver Diseases (AASLD).

Chronological evaluation of liver enhancement in patients with chronic liver disease at Gd-EOB-DTPA-enhanced 3-T MR imaging: does liver function correlate with enhancement?

PURPOSE

To investigate the chronological relationship between scan delay and liver enhancement for the hepatobiliary phase on Gd-EOB-DTPA-enhanced MRI and evaluate the effects of liver function on liver enhancement.

MATERIALS AND METHODS

Hepatobiliary-phase images were retrospectively evaluated in 125 patients with chronic liver disease. Hepatobiliary phase images were obtained at 5, 10, 15, and 20 min after injection. We calculated relative liver enhancement (RLE) at t min after injection by dividing the signal intensity (SI) of the liver at t min by precontrast SI. We compared RLE values at 5, 10, 15, and 20 min and evaluated the detectability of focal hepatic lesions. We analyzed the effect of liver function on RLE with the generalized linear model.

RESULTS

There was not significant difference in RLE and lesion detectability at 15 and 20 min. RLE in the Child-Pugh C group was significantly lower than in the Child-Pugh A and B groups. The serum albumin level and prothrombin time were significantly correlated with the liver enhancement.

CONCLUSION

A delay time of 15 min for the hepatobiliary phase was thought to be adequate in patients with mild liver dysfunction. The serum albumin level and prothrombin time would be predictive of liver enhancement in the hepatobiliary phase.

Hepatocellular carcinoma lesion characterization: single-institution clinical performance review of multiphase gadolinium-enhanced MR imaging--comparison to prior same-center results after MR systems improvements

PURPOSE

To measure diagnostic performance in the detection of hepatocellular carcinoma (HCC) by using the most recent technology and multiphase gadolinium-enhanced magnetic resonance (MR) imaging and to compare with earlier results at the same institution.

MATERIALS AND METHODS

This retrospective study was institutional review board approved and HIPAA compliant. Informed consent was obtained. Between January 2008 and April 2010, 101 patients underwent liver transplantation and pretransplantation abdominal MR imaging within 90 days. Prospective image interpretations from the clinical record were reviewed for documentation of HCC, including size, number, and location. Liver explant histologic examination provided the reference standard for lesion analysis and was performed in axial gross slices in conjunction with the MR imaging report for direct comparison. Tumors were categorized according to size (≥ 2 cm or <2 cm), and MR imaging detection sensitivity, specificity, predictive values, and accuracy were calculated according to category. The Fisher exact test was used to compare results from this study against prior reported results.

RESULTS

Thirty-five (34.7%) of 101 patients had HCC at explant analysis. Patient-based analysis of all lesions showed a sensitivity and specificity of 97.1% (34 of 35) and 100% (66 of 66), respectively. For lesions 2 cm or larger, MR imaging had a sensitivity and specificity of 100% (23 of 23) and 100% (78 of 78), respectively. For lesions smaller than 2 cm, MR imaging had a sensitivity and specificity of 82.6% (19 of 23) and 100% (78 of 78), respectively. Lesion-based sensitivity for all tumors was 91.4% (53 of 58) in the current study, compared with 77.8% in 2007 (P = .07). For lesions smaller than 2 cm, the sensitivity was 87.5% (28 of 32) in the current study, compared with 55.6% previously (P = .02).

CONCLUSION

MR imaging remains a highly accurate diagnostic method for the preoperative evaluation of HCC, and detection of small (<2 cm) tumors has been significantly improved compared with that of earlier studies.

Engineered nanoparticles for biomolecular imaging

In recent years, the production of nanoparticles (NPs) and exploration of their unusual properties have attracted the attention of physicists, chemists, biologists and engineers. Interest in NPs arises from the fact that the mechanical, chemical, electrical, optical, magnetic, electro-optical and magneto-optical properties of these particles are different from their bulk properties and depend on the particle size. There are numerous areas where nanoparticulate systems are of scientific and technological interest, particularly in biomedicine where the emergence of NPs with specific properties (e.g. magnetic and fluorescence) for contrast agents can lead to advancing the understanding of biological processes at the biomolecular level. This review will cover a full description of the physics of various imaging methods, including MRI, optical techniques, X-rays and CT. In addition, the effect of NPs on the improvement of the mentioned non-invasive imaging methods will be discussed together with their advantages and disadvantages. A detailed discussion will also be provided on the recent advances in imaging agents, such as fluorescent dye-doped silica NPs, quantum dots, gold- and engineered polymeric-NPs, superparamagnetic iron oxide NPs (SPIONs), and multimodal NPs (i.e. nanomaterials that are active in both MRI and optical methods), which are employed to overcome many of the limitations of conventional contrast agents (e.g. gadolinium).

Microvascular invasion in hepatocellular carcinoma: is it predictable with pretransplant MRI?

OBJECTIVE

The purpose of this article is to correlate clinicopathologic and MRI parameters with the presence of microvascular invasion at histopathologic examination in patients with hepatocellular carcinoma (HCC) who are undergoing liver transplantation.

MATERIALS AND METHODS

In this retrospective single-center study, we assessed 60 patients (47 men and 13 women; mean age, 58 years) with HCC who underwent liver transplantation and pretransplant MRI (performed within 90 days before liver transplantation). Two observers analyzed the following tumor parameters in consensus: number, size, T1 and T2 signal intensity, margins, presence of capsule or pseudocapsule, distance to closest vessel, distance to liver capsule, and quantitative tumor enhancement. The size and number of HCCs, tumor differentiation, and the presence or absence of microvascular invasion were determined at histopathologic examination. Odds ratios (ORs) were calculated and logistic regression analysis was performed to assess the utility of these clinicopathologic and imaging parameters for predicting microvascular invasion.

RESULTS

None of the clinical parameters or morphologic and enhancement MRI features of HCC was predictive of microvascular invasion. Tumor multifocality, on both MRI and pathologic examination, was the only variable that predicted microvascular invasion (OR = 2.43 and p = 0.013 for MRI; OR = 1.94 and p = 0.013 for pathologic examination). The presence of three or more tumors on MRI and four or more tumors at pathologic examination had high specificity (88.2% and 91.2%, respectively) for the prediction of microvascular invasion.

CONCLUSION

Tumor multifocality on MRI was the only parameter that correlated significantly with microvascular invasion. All other MRI tumor characteristics failed to predict microvascular invasion.

The role of hepatocyte-specific staining in liver pathology

The advantages of MRI in the investigation of liver disease are well documented. Recent developments, including fast scanning technique and new MRI contrast agents, enable improved detection and characterization of focal liver lesions. Therefore, a definitive diagnosis can be made avoiding invasive procedures, such as liver biopsy. In this article, a special emphasis is placed on the clinical use of combined perfusional and hepatocyte-selective MRI contrast agents, which allow us to obtain morphologic and vascular information, owing to the dynamic study, as well as functional information, owing to the hepatocyte-selective phase of enhancement. Different clinical scenarios are considered in order to highlight the proper use of the hepatocyte phase to noninvasively characterize and detect different focal liver lesions.

MR imaging of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common malignancy typically associated with chronic liver disease and is a leading cause of mortality among these patients. Prognosis is improved when detected early. MRI is the best imaging examination for accurate diagnosis. Although arterial enhancement with delayed washout, increased T2-weighted signal intensity, delayed capsular enhancement, restricted diffusion, and tumor thrombus are typical features, not all lesions demonstrate these findings. The radiologist must be familiar with these typical imaging characteristics, and less common appearances and associated findings of HCC, and must be able to differentiate them from those of lesions that mimic HCC. Knowledge of therapeutic options and how those are related to imaging findings is imperative to assist clinicians in managing these patients.

Analysis of gadobenate dimeglumine-enhanced MR findings for characterizing small (1-2-cm) hepatic nodules in patients at high risk for hepatocellular carcinoma

PURPOSE

To retrospectively identify magnetic resonance (MR) imaging findings that are associated with hepatocellular carcinoma (HCC) in 1-2-cm nodules detected at surveillance ultrasonography (US) and to propose newer MR imaging diagnostic criteria.

MATERIALS AND METHODS

Institutional research ethics board approval was obtained, and informed patient consent was waived. Among 145 consecutive patients who had 1-2-cm nodules that were newly detected at surveillance US, 108 patients underwent gadobenate dimeglumine-enhanced MR imaging. After excluding hemangiomas and unconfirmed nodules, the study sample comprised 96 patients with 116 nodules, including 43 HCCs and 73 benign nodules. MR imaging findings were assessed for signal intensity at each sequence. On the basis of the results of univariate and multivariable logistic regression analyses, several diagnostic criteria were developed by using combinations of MR imaging findings, which were then compared with the American Association for the Study of Liver Diseases (AASLD) practice guideline.

RESULTS

Univariate analysis revealed four imaging findings associated with HCC, including arterial phase hyperintensity, portal or delayed phase hypointensity (washout), hyperintensity on T2-weighted images, and hepatobiliary phase hypointensity (P < .001 for each). In the multivariable analysis, arterial phase hyperintensity (adjusted odds ratio [OR], 17.1; P = .003) and washout (adjusted OR, 11.7; P = .007) were associated with HCC. Of the developed criteria, the criteria including nodules fitting the AASLD practice guideline (arterial phase hyperintensity and washout) or nodules having three or more findings were considered most reasonable, showing improved sensitivity (77% [33 of 43] versus 67% [29 of 43], P = .048) and comparable specificity (95% [69 of 73] versus 99% [72 of 73], P = .09), as compared with AASLD practice guideline.

CONCLUSION

Alternative MR imaging criteria for diagnosing HCC in 1-2-cm nodules detected at surveillance US that can improve sensitivity compared with the AASLD practice guideline were proposed. A larger study is needed to verify the preliminary criteria in this study.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101549/-/DC1.

APASL and AASLD Consensus Guidelines on Imaging Diagnosis of Hepatocellular Carcinoma: A Review

Consensus guidelines for radiological diagnosis of hepatocellular carcinoma (HCC) have been drafted by several large international working groups. This article reviews the similarities and differences between the most recent guidelines proposed by the American Association for Study of Liver Diseases and the Asian Pacific Association for the Study of the Liver. Current evidence for the various imaging modalities for diagnosis of HCC and their relevance to the consensus guidelines are reviewed.

Gadoxetate Acid-Enhanced MR Imaging for HCC: A Review for Clinicians

Hepatocellular carcinoma (HCC) is increasingly being detected at an earlier stage, owing to the screening programs and regular imaging follow-up in high-risk populations. Small HCCs still pose diagnostic challenges on imaging due to decreased sensitivity and increased frequency of atypical features. Differentiating early HCC from premalignant or benign nodules is important as management differs and has implications on both the quality of life and the overall survival for the patients. Gadoxetate acid (Gd-EOB-DTPA, Primovist(®), Bayer Schering Pharma) is a relatively new, safe and well-tolerated liver-specific contrast agent for magnetic resonance (MR) imaging of the liver that has combined perfusion- and hepatocyte-specific properties, allowing for the acquisition of both dynamic and hepatobiliary phase images. Its high biliary uptake and excretion improves lesion detection and characterization by increasing liver-to-lesion conspicuity in the added hepatobiliary phase imaging. To date, gadoxetate acid-enhanced MRI has been mostly shown to be superior to unenhanced MRI, computed tomography, and other types of contrast agents in the detection and characterization of liver lesions. This review article focuses on the evolving role of gadoxetate acid in the characterization of HCC, differentiating it from other mimickers of HCC.

Manganese-enhanced MRI predicts the histological grade of hepatocellular carcinoma in potential surgical candidates

AIM

To evaluate the role of manganese-enhanced magnetic resonance (Mn-MRI) in predicting tumour differentiation prior to liver transplant or resection for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

The inclusion criteria were patients with HCC who underwent Mn-MRI prior to transplantation or resection from 2001-2008. T1-weighted MRI images were acquired at 0 and 24h after manganese dipyridoxal diphosphate (MnDPDP) intravenous contrast medium and reviewed prospectively. Manganese retention at 24h was correlated with tumour differentiation and disease-free survival.

RESULTS

Eighty-six patients underwent Mn-MRI (transplantation 60, resection 26); 114/125 lesions (91%) that were arterialised as evidenced at computed tomography (CT) and had manganese uptake on MRI were HCC. There were 11 false positives (9%) that were regenerative nodules. Ten of fourteen non-manganese-retaining HCC (71%) were poorly differentiated, compared with only 13/114 manganese-retaining HCC (11%) (p<0.0001). Sensitivity, specificity, positive and negative predictive values of non-retention of MnDPDP in predicting poorly differentiated tumours were 0.43, 0.96, 0.71 and 0.88. Median disease-free survival of patients with non-manganese-retaining HCC was less than for patients with manganese-retaining HCC (14±5 months versus 39±3 months, log rank p=0.025).

CONCLUSION

Non-manganese-retaining HCCs are likely to be poorly differentiated and have a poor prognosis. Manganese-enhanced MRI appears to have a role in preoperative assessment of HCC and warrants further evaluation.

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.

Comparison of portal venous and delayed phases of gadolinium-enhanced magnetic resonance imaging study of cirrhotic liver for the detection of contrast washout of hypervascular hepatocellular carcinoma

OBJECTIVE

To retrospectively compare portal venous phase (PVP) and delayed phase (DP) for the detection of tumor washout at gadobenate dimeglumine-enhanced liver magnetic resonance imaging (MRI) in cirrhotic patients with hypervascular hepatocellular carcinoma (HCC).

METHODS

Thirty-three patients with 55 HCCs underwent 1.5-T MRI by means of fat-suppressed T1-weighted sequence obtained before and after gadobenate dimeglumine administration, during early and late arterial phases, PVP (70 seconds), and DP (180 seconds). Detection rates of contrast washout of hypervascular HCCs and tumor-to-liver contrast on PVP and DP were measured and compared.

RESULTS

Among 54 hypervascular HCCs, washout was present in 24 (44%) of 54 tumors on PVP and in 44 (82%) of 54 on DP (P < 0.001). In 20 (37%) of 54 tumors, washout was deemed present only on DP. Delayed phase images yielded significantly higher mean tumor-to-liver contrast absolute values compared with PVP images (-24.5 [56.1] vs -9.3 [52.6], P = 0.001).

CONCLUSIONS

Delayed phase is superior to PVP for the washout detection of hypervascular HCC at gadobenate dimeglumine-enhanced MRI of cirrhotic liver.

Hepatocellular carcinoma and regenerating nodule in a 3-year-old child with Alagille syndrome

In Alagille syndrome, routine follow-up imaging of the liver plays an important role in detecting early parenchymal changes and to evaluate portal hypertension. Modern contrast-enhanced imaging methods not only allow early detection of focal liver lesions, but also enable further characterization of their nature and guide biopsy procedures. We present the US and MR imaging findings of hepatocellular carcinoma and a regenerating nodule in a 3-year-old child with Alagille syndrome.

Added value of 80 kVp images to averaged 120 kVp images in the detection of hepatocellular carcinomas in liver transplantation candidates using dual-source dual-energy MDCT: results of JAFROC analysis

BACKGROUND

To assess the added value of 80 kVp images to weighted average 120 kVp images for detecting hepatocellular carcinomas (HCCs) using dual-source, dual-energy MDCT.

MATERIALS AND METHODS

Forty-one HCCs in 42 patients who underwent liver transplantation (LT) were included. All patients underwent quadruple-phase CT using a 64-row dual-source, dual-energy MDCT with 80 kVp and 140 kVp. For 120 kVp, a linear blending ratio of 0.3 was chosen. Interval reviews for both simulated 120 kVp images without and with pure 80 kVp data were performed independently by two radiologists. They detected HCCs using a 4-point confidence scale. Tumor-to-liver contrast-to-noise ratio (CNR) was calculated and compared between the 80 kVp and simulated 120 kVp images. The additional diagnostic value of 80 kVp images was evaluated by jackknife alternative free-response receiver-operating characteristic (JAFROC) analysis.

RESULTS

There were 41 HCCs on pathology and 37 of the 41 HCCs were depicted on CT scan. The mean CNR of the 37 HCCs in late arterial and portal-phase images was significantly better in the 80 kVp images than in 120 kVp images. The average JAFROC figure of merit, however, was not significantly improved when 80 kVp was added. Furthermore, the number of false-positives was significantly increased in reader 1 when adding 80kVp data.

CONCLUSION

The addition of 80 kVp CT images to simulated 120 kVp images did not significantly improve the detection of HCCs despite of the significantly better CNR of 80 kVp images.

Imaging of the liver for hepatocellular cancer

BACKGROUND

Imaging of the liver is a key component in the detection, diagnosis, management, and follow-up of patients with hepatocellular carcinoma.

METHODS

The author uses his own experience as well as a review of pertinent literature to describe the capabilities and the limitations of the principal currently available imaging techniques for the liver.

RESULTS

Ultrasound is widely available, but sensitivity and specificity for small nodules are limited. Computed tomography effectively demonstrates extrahepatic lesions and can differentiate between cysts or hemangiomas and hepatocellular carcinomas. Magnetic resonance imaging better characterizes hepatic lesions, but positron emission tomography is of limited value.

CONCLUSIONS

Cross-sectional imaging with ultrasound, CT, or MRI is critical for nodule characterization in the cirrhotic liver, surgical planning of HCC, and treatment response evaluation.