Multidetector-row computed tomography (MDCT) for the diagnosis of hepatocellular carcinoma in cirrhotic candidates for liver transplantation: prevalence of radiological vascular patterns and histological correlation with liver explants

SIMAP500: A novel risk score to identify recipients at higher risk of hepatocellular carcinoma recurrence following liver transplantation

BACKGROUND

Recurrence of hepatocellular carcinoma (HCC) following liver transplantation (LT) has a devastating influence on recipients' survival; however, the risk of recurrence is not routinely stratified. Risk stratification is vital with a long LT waiting time, as that could influence the recurrence despite strict listing criteria.

AIM

This study aims to identify predictors of recurrence and develop a novel risk prediction score to forecast HCC recurrence following LT.

METHODS

A retrospective review of LT for HCC recipients at University Hospitals Birmingham between July 2011 and February 2020. Univariate and multivariate analyses were performed to identify recurrence predictors, based on which the novel SIMAP500 (satellite nodules, increase in size, microvascular invasion, AFP > 500, poor differentiation) risk score was proposed.

RESULTS

234 LTs for HCC were performed with a median follow-up of 5.3 years. Recurrence developed in 25 patients (10.7%). On univariate analyses, RETREAT score > 3, α-fetoprotein (AFP) at listing 100-500 and > 500, bridging, increased tumour size between imaging at the listing time and explant histology, increase in the size of viable tumour between listing and explant, presence of satellite nodules, micro- and macrovascular invasion on explant and poor differentiation of tumours were significantly associated with recurrence, based on which, the SIMAP500 risk score is proposed. The SIMAP500 demonstrated an excellent predictive ability (c-index = 0.803) and outperformed the RETREAT score (c-index = 0.73). SIMAP500 is indicative of the time to disease recurrence.

CONCLUSION

SIMAP500 risk score identifies the LT recipients at risk of HCC recurrence. Risk stratification allows patient-centric post-transplant surveillance programs. Further validation of the score is recommended.

Clinical Practice Guidelines For the Management of Hepatocellular Carcinoma: A Systematic Review

BACKGROUND

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths globally, including Australia. The absence of a consensus clinical practice guideline (CPG) specific to HCC management poses challenges in reducing morbidity, mortality, and improving patient recovery. This systematic review aims to evaluate the existing evidence and assess the potential of published guidelines, including those with an international scope, to provide guidance for healthcare professionals in Australia.

METHODS

Electronic search of MEDLINE, Embase, Cochrane Library, Google Scholar, and PubMed was conducted. Peer-reviewed English language articles from 2005 to June 2022 were included if they described management of HCC as part of an evidence-based overall management plan or CPG. The quality of the included CPGs was assessed by the Appraisal of Guidelines for Research and Evaluation II (AGREE II) tool.

RESULTS

Twenty-one articles from 16 regions throughout the world were included in this review. All included guidelines (n = 21, 100%) recommended evaluating cirrhosis, hepatitis B, and hepatitis C as potential risk factors of HCC. Obesity and non-alcoholic fatty liver disease were recommended by 19 CPGs (91%) as risk factor for HCC. Fourteen guidelines (67%) endorsed using the BCLC staging system. Eighteen guidelines (86%) recommended a multidisciplinary approach for the management of HCC. Eighteen guidelines (86%) advised that surveillance using ultrasound should be implemented in all cirrhotic patients every 6 months regardless of the cause of cirrhosis. AGREE II mean overall assessment score was 90% indicating that all guidelines included were highly recommended in majority of domains.

CONCLUSIONS

The included CPGs provided a comprehensive approach, emphasizing the evaluation of risk factors, utilization of the BCLC staging system, and the importance of a multidisciplinary approach. Regular surveillance using ultrasound for cirrhotic patients was widely recommended. An understanding of contemporary international CPGs can prioritize aspects of the management of HCC to assist healthcare professionals to develop a national guideline to enable standardized, comprehensive, and evidence-based care for patients with HCC.

Multimodality imaging of hepatocellular carcinoma and intrahepatic cholangiocarcinoma

Hepatocellular carcinoma and intrahepatic cholangiocarcinoma are the two most common primary malignant tumors of the liver. The similarities and variations in imaging characteristics that may aid in distinguishing between these two primary tumors will be discussed and outlined in this review. Knowledge of imaging techniques that are currently available would assist in the differentiation between these primary malignancies.

An improved diagnostic algorithm for subcentimeter hepatocellular carcinoma on gadoxetic acid-enhanced MRI

OBJECTIVES

Accurate diagnosis of subcentimeter hepatocellular carcinoma (HCC) is a challenge also with gadoxetic acid-enhanced MRI (EOB-MRI). This study aimed to assess the diagnostic accuracy of the Liver Imaging Reporting and Data System (LI-RADS) for subcentimeter HCC and to determine whether new diagnostic criteria (washout either on portal venous phase (PVP) or transitional phase (TP)) would improve the diagnostic performance.

METHODS

We evaluated 240 subcentimeter observations in 225 consecutive treatment-naïve patients at risk of HCC. Final diagnoses were 132 HCCs (all by pathology) and 108 non-HCC (41 by pathology and 67 by follow-up). Two radiologists assessed MR imaging features and assigned LI-RADS categories. A variety of diagnostic criteria were developed by combining significant MRI features based on washout on PVP or TP. Diagnostic performance was compared.

RESULTS

Non-rim arterial phase hyperenhancement (non-rim APHE), washout on PVP or TP, and hepatobiliary-phase hypointensity were significant predictors for subcentimeter HCC diagnosis according to multivariable analysis. One criterion (non-rim APHE and washout on PVP or TP) yielded higher sensitivity (68.2% vs. 56.8%, p = 0.011) with comparable specificity (91.7% vs. 92.6%, p > 0.999) compared to the LR-4 category. This criterion had improved sensitivity (68.2% vs. 49.2%, p < 0.001) and slightly decreased specificity (91.7% vs. 94.4%, p = 0.250) compared to non-rim APHE with washout on PVP.

CONCLUSIONS

LI-RADS exhibits modest diagnostic performance for subcentimeter HCC. Our new criterion (non-rim APHE and non-peripheral washout on PVP or TP) may increase the diagnostic sensitivity without compromised specificity compared to the LR-4 category.

KEY POINTS

• The LR-4 category shows modest diagnostic performance for the diagnosis of subcentimeter HCC on EOB-MRI with a sensitivity and specificity of 56.8% and 92.6%, respectively. • Non-rim APHE, non-peripheral washout on PVP or TP, and HBP hypointensity were independent predictors for the diagnosis of subcentimeter HCC. • The combination of non-rim APHE and non-peripheral washout on PVP or TP improves the sensitivity from 56.8 to 68.2% (p = 0.011) with comparable specificity (91.7 vs. 92.6%, p > 0.999).

Current Imaging Diagnosis of Hepatocellular Carcinoma

Simple Summary

The role of imaging in the management of hepatocellular carcinoma (HCC) has significantly evolved and expanded beyond the plain radiological confirmation of the tumor based on the typical appearance in a multiphase contrast-enhanced CT or MRI examination. The introduction of hepatobiliary contrast agents has enabled the diagnosis of hepatocarcinogenesis at earlier stages, while the application of ultrasound contrast agents has drastically upgraded the role of ultrasound in the diagnostic algorithms. Newer quantitative techniques assessing blood perfusion on CT and MRI not only allow earlier diagnosis and confident differentiation from other lesions, but they also provide biomarkers for the evaluation of treatment response. As distinct HCC subtypes are identified, their correlation with specific imaging features holds great promise for estimating tumor aggressiveness and prognosis. This review presents the current role of imaging and underlines its critical role in the successful management of patients with HCC.

Abstract

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer related death worldwide. Radiology has traditionally played a central role in HCC management, ranging from screening of high-risk patients to non-invasive diagnosis, as well as the evaluation of treatment response and post-treatment follow-up. From liver ultrasonography with or without contrast to dynamic multiple phased CT and dynamic MRI with diffusion protocols, great progress has been achieved in the last decade. Throughout the last few years, pathological, biological, genetic, and immune-chemical analyses have revealed several tumoral subtypes with diverse biological behavior, highlighting the need for the re-evaluation of established radiological methods. Considering these changes, novel methods that provide functional and quantitative parameters in addition to morphological information are increasingly incorporated into modern diagnostic protocols for HCC. In this way, differential diagnosis became even more challenging throughout the last few years. Use of liver specific contrast agents, as well as CT/MRI perfusion techniques, seem to not only allow earlier detection and more accurate characterization of HCC lesions, but also make it possible to predict response to treatment and survival. Nevertheless, several limitations and technical considerations still exist. This review will describe and discuss all these imaging modalities and their advances in the imaging of HCC lesions in cirrhotic and non-cirrhotic livers. Sensitivity and specificity rates, method limitations, and technical considerations will be discussed.

Simplified LI-RADS for Hepatocellular Carcinoma Diagnosis at Gadoxetic Acid-enhanced MRI

Background Although various modifications to the Liver Imaging Reporting and Data System (LI-RADS) at gadoxetic acid-enhanced MRI have been suggested, LI-RADS shows suboptimal sensitivity for hepatocellular carcinoma (HCC) and is perceived to be too complex. Purpose To evaluate clinical usefulness of a simplified LI-RADS for diagnosing HCCs of 30 mm or smaller at gadoxetic acid-enhanced MRI. Materials and Methods Patients who underwent gadoxetic acid-enhanced MRI examination and subsequent resection, transplantation, or biopsy for focal solid nodules of 30 mm or smaller between January 2019 and December 2020 at a single tertiary referral institution were retrospectively analyzed. Two strategies for simplified LI-RADS using one size criterion (≥10 mm) were evaluated (strategy A, using classifications for nodules of 10-19 mm for nodules both 10-19 mm and ≥20 mm; strategy B, using classifications for nodules ≥20 mm for nodules both 10-19 mm and ≥20 mm). Multivariable analysis was performed to determine significant ancillary features for HCC. Generalized estimating equations were used to compare diagnostic performance for LR-5 (definite HCC) between LI-RADS version 2018 and simplified LI-RADS. The time required for LI-RADS category assignment was compared between the two systems with use of a paired t test. Results A total of 645 nodules from 510 patients (mean age ± SD, 60 years ± 10; 393 men) were evaluated. Compared with strategy A, strategy B had a higher sensitivity of 74% (347 of 470 nodules [95% CI: 70, 78]) vs 73% (342 of 470 nodules [95% CI: 69, 77]) (P = .02) with the same specificity of 96% (168 of 175 nodules [95% CI: 92, 98]) vs 96% (168 of 175 nodules [95% CI: 92, 98]) (P > .99). In strategy B, transitional phase hypointensity was an independent ancillary feature for HCC (P = .04) in LR-4 of at least 10 mm with arterial phase hyperenhancement and no other major features. In all 645 nodules, simplified LI-RADS with use of both strategy B and transitional phase hypointensity had a higher sensitivity of 82% (387 of 470 nodules [95% CI: 79, 86]) vs 73% (343 of 470 nodules [95% CI: 69, 77]) (P < .001) than LI-RADS version 2018, without lower specificity (94%, 165 of 175 nodules [95% CI: 90, 97] vs 96%, 168 of 175 nodules [95% CI: 92, 98], P = .08). Compared with LI-RADS version 2018, simplified LI-RADS reduced the time for LI-RADS category assignment (44 seconds ± 23 vs 74 seconds ± 22, P < .001). Conclusion A simplified Liver Imaging Reporting and Data System was found to be clinically useful for diagnosing hepatocellular carcinomas of 30 mm or smaller at gadoxetic acid-enhanced MRI. © RSNA, 2022 Online supplemental material is available for this article.

A Narrative Review on LI-RADS Algorithm in Liver Tumors: Prospects and Pitfalls

Liver cancer is the sixth most detected tumor and the third leading cause of tumor death worldwide. Hepatocellular carcinoma (HCC) is the most common primary liver malignancy with specific risk factors and a targeted population. Imaging plays a major role in the management of HCC from screening to post-therapy follow-up. In order to optimize the diagnostic-therapeutic management and using a universal report, which allows more effective communication among the multidisciplinary team, several classification systems have been proposed over time, and LI-RADS is the most utilized. Currently, LI-RADS comprises four algorithms addressing screening and surveillance, diagnosis on computed tomography (CT)/magnetic resonance imaging (MRI), diagnosis on contrast-enhanced ultrasound (CEUS) and treatment response on CT/MRI. The algorithm allows guiding the radiologist through a stepwise process of assigning a category to a liver observation, recognizing both major and ancillary features. This process allows for characterizing liver lesions and assessing treatment. In this review, we highlighted both major and ancillary features that could define HCC. The distinctive dynamic vascular pattern of arterial hyperenhancement followed by washout in the portal-venous phase is the key hallmark of HCC, with a specificity value close to 100%. However, the sensitivity value of these combined criteria is inadequate. Recent evidence has proven that liver-specific contrast could be an important tool not only in increasing sensitivity but also in diagnosis as a major criterion. Although LI-RADS emerges as an essential instrument to support the management of liver tumors, still many improvements are needed to overcome the current limitations. In particular, features that may clearly distinguish HCC from cholangiocarcinoma (CCA) and combined HCC-CCA lesions and the assessment after locoregional radiation-based therapy are still fields of research.

Presence of tumour capsule on contrast-enhanced CT is associated with improved outcomes of stereotactic body radiation therapy in hepatocellular carcinoma patients

PURPOSE

Stereotactic body radiation therapy (SBRT) is a novel local therapy for the treatment of hepatocellular carcinoma (HCC). While effective, there is currently no reliable radiological marker to guide patient selection. In this study, we investigated the prognostic value of capsule appearance on contrast-enhanced computed tomography (CT) for patients undergoing SBRT.

MATERIALS AND METHODS

Between 2006 and 2017, 156 consecutive patients with Child-Pugh score class A/B and HCC ≥ 5 cm who underwent SBRT were retrospectively analysed. Baseline triple-phase CTs of the abdomen were reviewed for the presence of capsule appearances and correlated with objective response rate (ORR), overall survival (OS) and pattern of treatment failure.

RESULTS

Capsule appearance on CT was present in 83 (53.2%) patients. It was associated with improved ORR by Response Evaluation Criteria in Solid Tumours (RECIST) (60.2 vs. 24.7%, p < 0.001) and Modified Response Evaluation Criteria in Solid Tumours (mRECIST) (78.3 vs. 34.2%, p < 0.001). The presence of a capsule was also associated with superior 2‑year local control (89.1 vs. 51.4%, p < 0.001) and 2‑year OS (34.1 vs. 14.8%, p < 0.01). Hepatic out-field failure was the dominant mode of progression, which was less common in patients with intact capsule (54.2 vs. 60.3%, p = 0.01).

CONCLUSION

Capsule appearance on CT could potentially be a non-invasive prognostic marker for selecting HCC patients to undergo SBRT. A larger cohort is warranted to validate our findings.

Computed tomography 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 fourth in terms of cancer deaths. In clinical practice, computed tomography (CT) 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-foetoprotein, or both, either in surveillance programmes or in clinical settings. According to current guidelines, a single contrast-enhanced imaging study CT or magnetic resonance imaging (MRI) showing typical hallmarks of hepatocellular carcinoma in people with cirrhosis is valid to diagnose hepatocellular carcinoma. However, a significant number of hepatocellular carcinomas do not show typical hallmarks on imaging modalities, and hepatocellular carcinoma is, therefore, 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 CT may clarify whether the absence of benefit could be related to underdiagnosis. Furthermore, an assessment of the accuracy of CT 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 multidetector, multiphasic contrast-enhanced CT for the diagnosis of hepatocellular carcinoma of any size and at any stage in adults with chronic liver disease, either in a surveillance programme or in a clinical setting. Secondary: to assess the diagnostic accuracy of CT for the diagnosis of resectable hepatocellular carcinoma in adults with chronic liver disease.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Trials Register, Cochrane Hepato-Biliary Diagnostic-Test-Accuracy Studies Register, the Cochrane Library, MEDLINE, Embase, LILACS, Science Citation Index Expanded, and Conference Proceedings Citation Index - Science until 4 May 2021. We applied no language or document-type restrictions.

SELECTION CRITERIA

Studies assessing the diagnostic accuracy of CT 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 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 21 studies, with a total of 3101 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 in the patient selection domain, we judged 14% (3/21) of studies to be at low concern and 86% (18/21) of studies to be at high concern owing to characteristics of the participants who were on waiting lists for orthotopic liver transplantation. CT for hepatocellular carcinoma of any size and stage: sensitivity 77.5% (95% CI 70.9% to 82.9%) and specificity 91.3% (95% CI 86.5% to 94.5%) (21 studies, 3101 participants; low-certainty evidence). CT for resectable hepatocellular carcinoma: sensitivity 71.4% (95% CI 60.3% to 80.4%) and specificity 92.0% (95% CI 86.3% to 95.5%) (10 studies, 1854 participants; low-certainty evidence). In the three studies at low concern for applicability (861 participants), we found sensitivity 76.9% (95% CI 50.8% to 91.5%) and specificity 89.2% (95% CI 57.0% to 98.1%). 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

In the clinical pathway for the diagnosis of hepatocellular carcinoma in adults with chronic liver disease, CT has roles as a confirmatory test for hepatocellular carcinoma lesions, and for staging assessment. We found that using CT in detecting hepatocellular carcinoma of any size and stage, 22.5% of people with hepatocellular carcinoma would be missed, and 8.7% of people without hepatocellular carcinoma would be unnecessarily treated. For resectable hepatocellular carcinoma, we found that 28.6% of people with resectable hepatocellular carcinoma would improperly not be resected, while 8% 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.

Assessment of factors affecting washout appearance of hepatocellular carcinoma on CT

OBJECTIVES

To identify independent imaging and histopathologic factors that affect washout appearance of hepatocellular carcinoma (HCC) in CT images.

METHODS

This retrospective study included 264 patients who had undergone surgical resection for treatment-naïve single HCC between January 2014 and December 2015 and had available preoperative multiphasic CT images. Two reviewers evaluated the CT imaging features of HCC using LI-RADS v2018. The "washout" was visually assessed in portal venous or equilibrium phases. Depending on the presence of washout appearance of HCC, all patients were divided into "washout" (n = 228) and "no washout" (n = 36) groups. Multivariable logistic regression analysis was used to identify factors associated with the absence of washout appearance of HCC.

RESULTS

A total of 264 HCCs (median size, 2.6 cm) were analyzed. Histologically proven hepatic steatosis (macrovesicular steatosis ≥ 5%) (odds ratio [OR], 2.65; 95% confidence interval [CI], 1.05-6.74; p = 0.040), tumor capsule on histopathology (OR, 0.17; 95% CI, 0.06-0.50; p = 0.001), and mosaic appearance on CT image (OR, 0.34; 95% CI, 0.14-0.85; p = 0.021) were independent factors associated with the absence of washout appearance of HCC. In 189 patients with available unenhanced CT images, CT-diagnosed hepatic steatosis was also an independent factor for the absence of washout appearance of HCC (OR, 9.26; 95% CI, 3.06-28.02; p < 0.001).

CONCLUSIONS

Washout appearance of HCC in CT images could be obscured in both histologically proven hepatic steatosis and CT-diagnosed hepatic steatosis, and could be enhanced with tumor capsule on histopathology and mosaic appearance on CT image.

KEY POINTS

• Hepatic steatosis is an independent factor related to the absence of washout appearance of hepatocellular carcinoma in CT images, in both histologically proven hepatic steatosis and CT-diagnosed hepatic steatosis. • Both histologically proven hepatic steatosis and CT-diagnosed hepatic steatosis have higher odds of absence of washout appearance of hepatocellular carcinoma compared to non-steatotic liver. • Tumor capsule on histopathology and mosaic appearance on CT image are independent factors that enhance the probability that washout appearance of hepatocellular carcinoma is visible.

Comparison of LI-RADS with other non-invasive liver MRI criteria and radiological opinion for diagnosing hepatocellular carcinoma in cirrhotic livers using gadoxetic acid with histopathological explant correlation

AIM

To establish the diagnostic accuracy of the Liver Imaging Reporting and Data System (LI-RADS) for hepatocellular carcinoma (HCC) and compare its performance to that of international criteria from European Assofor the Study of the Liver (EASL), Japan Society of Hepatology (JSH), Asian Pacific Association for the Study of the Liver (APASL), and Organ Procurement and Transplantation Network (OPTN), and to the reporting radiologist's overall opinion regarding the probability of a nodule being a HCC by correlating with a histological diagnosis from whole liver explants.

MATERIALS AND METHODS

The present single-centre, retrospective review selected participants based on the following criteria: adults (≥18 years) listed for liver transplantation in 2014/2015, with liver cirrhosis at the time of magnetic resonance imaging (MRI) with hepatocyte specific contrast agent, and at least one liver lesion ≥10 mm on MRI with histology from subsequent liver explant for comparison. Each lesion was assessed against international criteria and given a "radiologist opinion" score of 1-5 (1 = definitely benign, 5 = definitely HCC).

RESULTS

Total 268 patient records were reviewed, with 105 eligible lesions identified from 47 patients. Median lesion size was 15.5 mm (range 10-68 mm). Sensitivity (%), specificity (%), and positive predictive value (PPV; %) for LI-RADS LR5 was 45, 89, and 89, for LI-RADS LR4+5 + TIV was 61, 80, and 86, for EASL was 44, 86 and 86, for JSH/APASL was 64, 81, and 87, for OPTN was 36, 90, and 88, and for "radiologist impression" of probably or definitely HCC was 79, 79, and 88 respectively.

CONCLUSIONS

MRI has moderate sensitivity and good specificity for the diagnosis of HCC with considerable variation depending on criteria used. OPTN criteria have the best specificity, but low sensitivity. "Radiologist opinion" gives highest overall accuracy with increases in sensitivity and reduction in specificity when compared to the imaging criteria.

Gadoxetic acid-enhanced MRI for diagnosis of hepatocellular carcinoma in patients with chronic liver disease: can hypointensity on the late portal venous phase be used as an alternative to washout?

PURPOSE

To investigate the added value of considering hypointensity on late portal venous phase (LPVP) images as washout for diagnosis of hepatocellular carcinoma (HCC) using gadoxetic acid-enhanced MRI (Gd-EOB-MRI) in patients with chronic liver disease (CLD).

METHODS

This retrospective study comprised 97 patients at high risk for HCC who underwent Gd-EOB-MRI including unenhanced, multi-arterial phase, conventional portal venous phase (CPVP, 60 s), and LPVP (mean, 99.9 ± 9.1 s; range, 90-119 s) images. A total of 115 hepatic lesions were identified by histopathological or clinical diagnosis. Three independent radiologists assessed the MRI images by consensus. Diagnosis of HCC was made using criteria of arterial hyperenhancement and hypointensity relative to the surrounding liver parenchyma (1) on CPVP or (2) on CPVP and/or LPVP images. The generalized estimating equation was used to compare diagnostic performance for HCC between Criterion 1 and 2.

RESULTS

In 82 HCCs, the frequency of hypointensity differed significantly between the CPVP and LPVP images (64.6% [53/82] vs. 84.1% [69/82], P < 0.001). Among 33 non-HCCs, two cHCC-CCs showed additional hypointensity on LPVP than CPVP images (33.3% [11/33] vs. 39.4% [13/33], P = 0.500). Criterion 2 provided significantly greater sensitivity for diagnosing HCC than Criterion 1 (54.9% [45/82] vs. 74.4% [61/82], P < 0.001), with relatively little reduction in specificity (90.9% [30/33] vs. 84.8% [28/33], P = 0.145).

CONCLUSION

Additional use of LPVP hypointensity as washout could significantly improve sensitivity for HCC diagnosis when utilizing Gd-EOB-MRI in patients with CLD, without a significant decrease in specificity.

ACR Appropriateness Criteria® Chronic Liver Disease

The liver fibrosis stage is the most important clinical determinate of morbidity and mortality in patients with chronic liver diseases. With newer therapies, liver fibrosis can be stabilized and possibly reversed, thus accurate diagnosis and staging of liver fibrosis are clinically important. Ultrasound, CT, and conventional MRI can be used to establish the diagnosis of advanced fibrosis/cirrhosis but have limited utility for assessing earlier stages of fibrosis. Elastography-based ultrasound and MRI techniques are more useful for assessment of precirrhotic hepatic fibrosis. In patients with advanced fibrosis at risk for hepatocellular carcinoma (HCC), ultrasound is the surveillance modality recommended by international guidelines in nearly all circumstances. However, in patients in whom ultrasound does not assess the liver well, including those with severe steatosis or obesity, multiphase CT or MRI may have a role in surveillance for HCC. Both multiphase CT and MRI can be used for continued surveillance in patients with a history of HCC, and contrast-enhanced ultrasound may have an emerging role in this setting. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Multi-marker diagnosis method for early Hepatocellular Carcinoma based on surface plasmon resonance

Early diagnosis of Hepatocellular Carcinoma (HCC) is an important means to raise the survival rate of patients. Multi-marker combined detection is a powerful tool of early HCC diagnosis. Traditional detection methods are not effective and accurate because it is difficult to achieve combined detection of multiple markers. In this paper, we selected Alpha Fetoprotein (AFP) and miRNA-125b as the combined detection markers to improve the simultaneously diagnostic sensitivity and specificity. The anti-AFP monoclonal antibody and the DNA probes paired with the miRNA-125b were modified on the surface of surface plasmon resonance (SPR) sensor respectively to specifically recognize AFP and miRNA-125b in serum. In order to enhance the SPR response signal and detection sensitivity, Double Antibody Sandwich Method (DASM) and S9.6 antibody enhanced method were applied to achieve low detection limit of the two markers. Experimental results showed that AFP (25-400 ng/mL) was accurately detected by DASM and the detection limit of miRNA-125b by S9.6 antibody enhanced method reached 123.044 pM. These results verified the feasibility of the multi-marker detection method in early diagnosis of HCC.

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.

Evaluation of treatment response in hepatocellular carcinoma in the explanted liver with Liver Imaging Reporting and Data System version 2017

OBJECTIVE

To investigate the performance of Liver Imaging Reporting and Data System (LI-RADS) v2017 treatment response algorithm for predicting hepatocellular carcinoma (HCC) viability after locoregional therapy (LRT) using the liver explant as reference.

METHODS

One hundred fourteen patients with 206 HCCs who underwent liver transplantation (LT) after LRT for HCCs were included in this retrospective study. Two radiologists independently evaluated tumor viability using the LI-RADS and modified RECIST (mRECIST) with CT and MRI, respectively. The sensitivity and specificity of arterial phase hyperenhancement (APHE) and LR-TR viable criteria (any of three findings: APHE, washout, and enhancement pattern similar to pretreatment imaging) were compared using logistic regression. Receiver operating characteristics (ROC) analysis was used to compare the diagnostic performance between LI-RADS and mRECIST and between CT and MRI.

RESULTS

The sensitivity and specificity for diagnosing viable tumor were not significantly different between APHE alone and LR-TR viable criteria on CT (p = 0.054 and p = 0.317) and MRI (p = 0.093 and p = 0.603). On CT, the area under the ROC curve (AUC) of LI-RADS was significantly higher than that of mRECIST (0.733 vs. 0.657, p < 0.001). On MRI, there was no significant difference in AUCs between LI-RADS and mRECIST (0.802 vs. 0.791, p = 0.500). Intra-individual comparison of CT and MRI showed comparable AUCs using LI-RADS (0.783 vs. 0.795, p = 0.776).

CONCLUSIONS

LI-RADS v2017 treatment response algorithm showed better diagnostic performance than mRECIST on CT. With LI-RADS, CT and MRI were comparable to diagnose tumor viability of HCC after LRT.

KEY POINTS

• Using Liver Imaging Reporting and Data System (LI-RADS) v2017 treatment response algorithm, the viability of hepatocellular carcinoma (HCC) after locoregional therapy (LRT) can be accurately diagnosed. • LI-RADS v2017 treatment response algorithm is superior to modified Response Evaluation Criteria in Solid Tumors for evaluating HCC viability using CT. • Either CT or MRI can be performed to assess tumor viability after LRT using LI-RADS v2017 treatment response algorithm.

Predicting hepatocellular carcinoma recurrences: A data-driven multiclass classification method incorporating latent variables

Hepatocellular carcinoma (HCC), a malignant form of cancer, is frequently treated with surgical resections, which have relatively high recurrence rates. Effective recurrence predictions enable physicians' timely detections and adequate therapeutic measures that can greatly improve patient care and outcomes. Toward that end, predictions of early versus late HCC recurrences should be considered separately to reflect their distinct onset time horizons, clinical causes, underlying clinical etiology, and pathogenesis. We propose a novel Bayesian network-based method to predict different HCC recurrence outcomes by considering the respective recurrence evolution paths. Typical patient information obtained in early stages is insufficiently informative to predict recurrence outcomes accurately, due to the lack of subsequent patient progression information. Our method alleviates such information deficiency constraints by incorporating an independent latent variable, dominant recurrence type, to regulate recurrence outcome predictions (early, late, or no recurrence). We use a real-world HCC data set to evaluate the proposed method, relative to three prevalent benchmark techniques. Overall, the results show that our method consistently and significantly outperforms all the benchmark techniques in terms of accuracy, precision, recall, and F-measures. For increased robustness, we use another data set to perform an out-of-sample evaluation and obtain similar results. This study thus contributes to HCC recurrence research and offers several implications for clinical practice.

Spectral Photon-Counting Computed Tomography (SPCCT): in-vivo single-acquisition multi-phase liver imaging with a dual contrast agent protocol

Diagnostic imaging of hepatocellular carcinoma (HCC) requires a liver CT or MRI multiphase acquisition protocol. Patients would benefit from a high-resolution imaging method capable of performing multi-phase imaging in a single acquisition without an increase in radiation dose. Spectral Photon-Counting Computed Tomography (SPCCT) has recently emerged as a novel and promising imaging modality in the field of diagnostic radiology. SPCCT is able to distinguish between two contrast agents referred to as multicolor imaging because, when measuring in three or more energy regimes, it can detect and quantify elements with a K-edge in the diagnostic energy range. Based on this capability, we tested the feasibility of a dual-contrast multi-phase liver imaging protocol via the use of iodinated and gadolinated contrast agents on four healthy New Zealand White (NZW) rabbits. To perform a dual-contrast protocol, we injected the agents at different times so that the first contrast agent visualized the portal phase and the second the arterial phase, both of which are mandatory for liver lesion characterization. We demonstrated a sensitive discrimination and quantification of gadolinium within the arteries and iodine within the liver parenchyma. In the hepatic artery, the concentration of gadolinium was much higher than iodine (8.5 ± 3.9 mg/mL versus 0.7 ± 0.1 mg/mL) contrary to the concentrations found in the liver parenchyma (0.5 ± 0.3 mg/mL versus 4.2 ± 0.3 mg/mL). In conclusion, our results confirm that SPCCT allows in-vivo dual contrast qualitative and quantitative multi-phase liver imaging in a single acquisition.

Gadoxetic Acid-enhanced MRI of Hepatocellular Carcinoma: Value of Washout in Transitional and Hepatobiliary Phases

Background Current Liver Imaging Reporting and Data System guidelines define the washout appearance of gadoxetic acid-enhanced MRI only during the portal venous phase. Defining washout only during the portal venous phase may lead to lower sensitivity for diagnosis of hepatocellular carcinoma (HCC). Purpose To compare the diagnostic performances of three gadoxetic acid-enhanced MRI criteria for HCC according to the phases during which washout appearance was determined. Materials and Methods In this retrospective study, patients with a hepatic nodule detected at US surveillance for HCC from January to December 2012 underwent gadoxetic acid-enhanced MRI. Three diagnostic MRI criteria for HCC were defined according to the phases during which washout appearance was observed, with the presence of arterial phase hyperenhancement and hypointensity noted (a) only during the portal venous phase, with washout confined to the portal venous phase; (b) during the portal venous phase or transitional phase, with washout extended to the transitional phase; or (c) during the portal venous, transitional, or hepatobiliary phase, with washout extended to the hepatobiliary phase. If a nodule showed marked T2 hyperintensity or a targetoid appearance, it was precluded from the diagnosis of HCC. The sensitivity and specificity were compared by using a generalized estimating equation. Results A total of 178 patients were included (mean age ± standard deviation, 55.3 years ± 9.1) with 203 surgically confirmed hepatic nodules (186 HCCs and 17 non-HCCs) measuring 3.0 cm or smaller. The sensitivity with washout extended to the hepatobiliary phase (95.2% [177 of 186]) was better than that with washout extended to the transitional phase (90.9% [169 of 186]; P = .01) and washout confined to the portal venous phase (75.3% [140 of 186]; P < .01). The specificity with extensions of washout to the transitional phase and hepatobiliary phase (82% [14 of 17] for both) was similar to that obtained with washout confined to the portal venous phase (94.1% [16 of 17]) (P = .47). Conclusion After exclusion of typical hemangiomas and nodules with a targetoid appearance, extending washout appearance to the transitional or hepatobiliary phase (instead of restricting it to the portal venous phase) allowed higher sensitivity without a reduction in specificity. © RSNA, 2019 See also the editorial by Fowler and Sirlin in this issue.

Optimal criteria for hepatocellular carcinoma diagnosis using CT in patients undergoing liver transplantation

OBJECTIVE

To compare the diagnostic performance of various guidelines for hepatocellular carcinoma (HCC) diagnosis using computed tomography (CT) in patients undergoing liver transplantation (LT).

METHODS

In total, 216 patients who underwent preoperative CT and subsequent LT were included. Two radiologists retrospectively evaluated focal hepatic lesions independently according to various guidelines and allocated patients according to the Milan criteria. The diagnostic performance of the guidelines was compared using alternative free-response receiver-operating characteristics (AFROC) analysis with bootstrapping. Comparisons of sensitivity, specificity, and accuracy of patient allocation based on the Milan criteria between guidelines were performed using logistic regression with generalized estimating equations (GEE).

RESULTS

Fifty-two of 216 patients had 87 HCCs. The reader-averaged figure of merit obtained using AFROC analysis was 0.738 for the AASLD/EASL or KLCSG-NCC guidelines and 0.728 for the LI-RADS v2014 or OPTN/UNOS (bootstrapping, p = 0.005). The per-lesion sensitivity for HCCs (all and 1-2-cm lesions) was significantly higher with the AASLD/EASL (37.9-41.4% and 30.8-41.0%) than with LI-RADS (28.7% and 15.4-18.0%) (logistic regression with GEE, p = 0.008 and 0.030 for reader 1 and p = 0.005 for reader 2). The per-patient specificity (98.8-99.4%) was the same for all guidelines. The accuracy of the Milan criteria was 81.5-83.3% without significant differences among the four guidelines (logistic regression with GEE, p > 0.05).

CONCLUSION

AASLD/EASL showed higher diagnostic performance and sensitivity, particularly for 1-2-cm HCCs, and the same specificity with LI-RADS. All guidelines are comparable for patient allocation based on the Milan criteria for LT.

KEY POINTS

• The overall diagnostic performance of CT for HCC diagnosis was highest with AASLD/EASL. • AASLD/EASL showed higher sensitivity for diagnosis of 1-2-cm HCCs than LI-RADS. • The accuracy of the Milan criteria using CT was comparable among the four guidelines.

Angio-Computed Tomograph-Guided Immediate Lipiodol Computed Tomograph for Diagnosis of Small Hepatocellular Carcinoma Lesions during Transarterial Chemoembolization

BACKGROUND

The diagnosis and treatment of small hepatocellular carcinoma (HCC) play a vital role in the prognosis of patients with HCC. The purpose of our study was to evaluate angio-computed tomography (angio-CT)-guided immediate lipiodol CT (a CT scan performed immediately after transarterial chemoembolization [TACE]) in the diagnosis of potential HCCs ≤1 cm in diameter.

METHODS

This study retrospectively analyzed 31 patients diagnosed with HCCs after routine imaging (contrast-enhanced CT or magnetic resonance imaging) or pathologic examinations with undefined or undetermined tumor lesions (diameter ≤1 cm) from February 2016 to September 2016. After TACE guided by digital subtraction angiography of the angio-CT system, potential HCC lesions with a diameter ≤1 cm were diagnosed by immediate lipiodol CT. The number of well-demarcated lesions was recorded to calculate the true positive rate. The correlation between the number of small HCCs detected by immediate lipiodol CT and the size of HCC lesions (diameter >1 cm) diagnosed preoperatively was analyzed 1 month after TACE. A paired t-test was used to analyze differences in liver function. Pearson analysis was used to analyze correlation. Chi-square test was used to compare the rates.

RESULTS

Fifty-eight lesions were detected on preoperative routine imaging examinations in 31 patients including 15 lesions with a diameter ≤1 cm. Ninety-one lesions were detected on immediate lipiodol CT, of which 48 had a diameter ≤1 cm. After 1 month, CT showed that 45 lesions had lipiodol deposition and three lesions had lipiodol clearance. Correlation analysis showed that the number of small HCCs detected by lipiodol CT was positively correlated with the size of HCC lesions diagnosed by conventional imaging examination (R2 = 0.54, P < 0.05).

CONCLUSION

Immediate lipiodol CT may be a useful tool in the diagnosis of potential HCC lesions with a diameter of ≤1 cm.

Diagnostic accuracy of contrast-enhanced dynamic CT for small hypervascular hepatocellular carcinoma and assessment of dynamic enhancement patterns: Results of two-year follow-up using cone-beam CT hepatic arteriography

Objective

To evaluate the accuracy of CT for small, hypervascular hepatocellular carcinomas (HCCs) and assess the enhancement patterns on CT.

Materials and methods

Ninety-nine patients who underwent cone-beam CT hepatic arteriography (CBCT-HA) during initial chemoembolization for HCC suspected on CT were enrolled in this study. A total of 297 hypervascular HCCs (142 ≥ 1 cm, 155 < 1 cm) were confirmed as HCCs based on two-year follow-up CT and CBCT-HA images. During the two-year follow-up, pre-existing hypervascular foci on CBCT-HA were regarded as HCCs at the initial presentation. Two radiologists categorized HCCs according to the following enhancement patterns on CT: type I, arterial enhancement and washout; type II, arterial enhancement without washout; and type III, no arterial enhancement. Two blinded reviewers rated the possibility of HCC.

Results

For the 297 HCCs, the enhancement patterns according to size were as follows: type I ≥1 cm in 114 HCCs; type I <1 cm in 40 HCCs; type II ≥1 cm in 16 HCCs; type II <1 cm in 37 HCCs; type III ≥1 cm in 12 HCCs; and type III <1 cm in 10 HCCs. The remaining 68 HCCs (22.9%) were not detected on CT. The detection rates of HCCs ≥ 1 cm were 83.1%, 76.8%, and 83.1% in the formal report for reviewer 1 and reviewer 2. In comparison, the detection rates of HCCs < 1 cm were 20.6%, 17.4%, and 17.4% in the formal report for reviewer 1 and reviewer 2.

Conclusion

Many subcentimeter sized hypervascular HCCs were frequently missed or not evident on CT at the initial diagnostic workup. CT has limitations for diagnosing HCCs that are <1 cm in size or have atypical enhancement patterns.

Accuracy of Computed Tomography in the Assessment of Milan Criteria in Liver Transplantation for Hepatocellular Carcinoma

BACKGROUND

Despite worldwide debate on optimal selection of patients with hepatocellular carcinoma (HCC) for liver transplantation, the Milan criteria remain the benchmark for comparisons. Moreover, morphologic tumor features are universally considered important in pretransplant patient evaluation. The aim of this study was to establish the diagnostic accuracy of multiphasic computed tomography (CT) in assessing HCC burden before liver transplantation with special reference to Milan criteria fulfillment.

METHODS

This retrospective study was based on a data from 27 HCC patients after liver transplantation with available CT performed within 30 days pretransplant. CT results were compared with explant pathology with respect to Milan criteria fulfillment, tumor number, and diameter of the largest tumor.

RESULTS

Out of 19 patients within the Milan criteria on CT, 3 fell beyond the criteria on explant pathology with a gross underestimation rate of 15.8%. Out of 8 patients beyond the Milan criteria on CT, 3 were within the criteria on explant pathology with a gross overestimation rate of 37.5%. Regarding tumor number, CT was accurate only in 14 patients (51.9%), while overestimation and underestimation occurred in 5 (18.5%) and 8 (29.6%) patients, respectively. Overestimation and underestimation of largest tumor size by at least 1 cm occurred in 4 (14.8%) and 7 (25.9%) patients, respectively.

DISCUSSION

Multiphasic CT is associated with a remarkable risk of both under- and overestimation of HCC burden before transplantation. Transplant eligibility should not be solely based on CT results.

Evidence Supporting LI-RADS Major Features for CT- and MR Imaging-based Diagnosis of Hepatocellular Carcinoma: A Systematic Review

The Liver Imaging Reporting and Data System (LI-RADS) standardizes the interpretation, reporting, and data collection for imaging examinations in patients at risk for hepatocellular carcinoma (HCC). It assigns category codes reflecting relative probability of HCC to imaging-detected liver observations based on major and ancillary imaging features. LI-RADS also includes imaging features suggesting malignancy other than HCC. Supported and endorsed by the American College of Radiology (ACR), the system has been developed by a committee of radiologists, hepatologists, pathologists, surgeons, lexicon experts, and ACR staff, with input from the American Association for the Study of Liver Diseases and the Organ Procurement Transplantation Network/United Network for Organ Sharing. Development of LI-RADS has been based on literature review, expert opinion, rounds of testing and iteration, and feedback from users. This article summarizes and assesses the quality of evidence supporting each LI-RADS major feature for diagnosis of HCC, as well as of the LI-RADS imaging features suggesting malignancy other than HCC. Based on the evidence, recommendations are provided for or against their continued inclusion in LI-RADS. © RSNA, 2017 Online supplemental material is available for this article.

Diagnostic accuracy of indocyanine green fluorescence imaging and multidetector row computed tomography for identifying hepatocellular carcinoma with liver explant correlation

AIM

Indocyanine green (ICG)-fluorescence imaging is useful for detecting hepatocellular carcinoma (HCC) during surgery, but its accuracy has not been compared to that of multidetector row computed tomography (MDCT) with liver explant correlation. The aim of the present study was to clarify the precise diagnostic accuracy of ICG-fluorescence imaging for detecting HCC in a whole explant liver survey.

METHODS

Thirty-three patients with end-stage liver disease (mean age, 53 years) were prospectively enrolled in the present study. The mean Model for End-stage Liver Disease score was 14.6. One month before and 1 week prior to living donor liver transplantation, all patients underwent MDCT and administration of ICG. Following whole liver resection, the explanted liver was sliced. Gross examination and ICG-fluorescence imaging of both sides of the cut specimen was carried out and all focal liver lesions were recorded.

RESULTS

Pathologic examination diagnosed 18 of 84 focal liver lesions as HCC. Of those, MDCT and ICG-fluorescence imaging diagnosed 12 and 13 HCCs, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MDCT were 66.7%, 92.4%, 70.6%, 91.0%, and 86.9%, respectively, compared with those of ICG-fluorescence imaging at 72.2%, 31.8%, 22.4%, 80.8%, and 40.5%, respectively.

CONCLUSION

The sensitivity of ICG-fluorescence imaging for detecting HCC with liver explant correlation was similar to that of MDCT. However, ICG-fluorescence imaging had low specificity in the setting of decompensated cirrhotic explant liver correlation.

Diagnostic Imaging of Hepatocellular Carcinoma - A Pictorial Essay

Hepatocellular carcinoma (HCC) is the most common primary liver cancer, which develops mostly in the setting of chronic liver disease. European Association for the Study of the Liver (EASL) and European Organization for Research and Treatment of Cancer (EORTC) prepared guidelines for screening, follow-up and diagnosis of HCC to facilitate decision making and optimize both diagnostic and therapeutic protocols. The review briefly describes etiology, epidemiology and histopathology of HCC and presents EASL-EORTC guidelines for surveillance and diagnosis of HCC. Target population and screening algorithm is presented in the surveillance section. Ultrasound imaging of HCC and the role of contrast enhanced ultrasound are described as well as the value of laboratory tests in screening. Further, radiological features of HCC in multiphase CT and dynamic contrast enhanced MRI and diagnostic criteria are presented. Additionally, the advantages of advanced techniques in MRI such as diffusion weighed imaging and the use of hepatocyte-specific contrast agents are discussed. Lastly, the EASL-EORTC guidelines are compared with the guidelines of the American Association for the Study of Liver Diseases and the Japan Society of Hepatology. Also LI-RADS and the Barcelona Clinic Liver Cancer classification are mentioned. In the near future, due to the ongoing advances in imaging a revision of the guidelines may be expected.

Added value of smooth hypointense rim in the hepatobiliary phase of gadoxetic acid-enhanced MRI in identifying tumour capsule and diagnosing hepatocellular carcinoma

OBJECTIVES

To examine the added value of considering smooth hypointense rim in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI as capsule appearance for diagnosing tumour capsules and hepatocellular carcinoma (HCC).

METHODS

A total of 377 hepatic lesions (330 HCCs, 35 non-HCC malignancies and 12 benign) were included from 345 patients who underwent resection after MRI between January 2008 and December 2011. Two radiologists assessed the presence or absence of conventional capsule appearance and smooth hypointense rim in the HBP, and categorized each hepatic lesion according to the Liver Imaging Reporting and Data System. Difference in diagnostic performance was evaluated using the generalized estimating equation method.

RESULTS

For identifying capsule, the sensitivity and accuracy of HBP hypointense rim were significantly higher than those of conventional capsule appearance (81.5 % vs. 57.8 % and 76.1 % vs. 59.4 %, respectively; P < 0.001). For diagnosing HCC, the sensitivity and accuracy of LR-5 or LR-5 V were significantly higher when the HBP hypointense rim was also considered capsule appearance (83 % vs. 72.7 % and 84.1 % vs. 75.1 %, respectively; P < 0.001), with the same specificity (91.5 %).

CONCLUSIONS

Regarding smooth hypointense rim in the HBP as capsule appearance could improve the detection of tumour capsule and the diagnosis of HCC.

KEY POINTS

• Identifying tumour capsule is important for diagnosis of hepatocellular carcinoma (HCC). • Gadoxetic acid-enhanced MRI provides hepatobiliary phase (HBP) images. • Smooth hypointense rim seen in HBP may represent tumour capsule. • Regarding smooth hypointense rim as capsule appearance may improve HCC diagnosis.

Comparison of hepatocellular carcinoma conspicuity on hepatobiliary phase images with gadoxetate disodium vs. delayed phase images with extracellular cellular contrast agent

OBJECTIVE

To compare the conspicuity of hepatocellular carcinoma (HCC) on hepatobiliary phase of gadoxetate disodium-enhanced vs. delayed phase of gadodiamide-enhanced MR images, relative to liver function.

METHODS AND MATERIALS

We retrospectively identified 86 patients with newly diagnosed HCC between 2010 and 2013 and recorded the severity of liver disease by Child-Pugh class (CPC). 38 patients had gadodiamide-enhanced 5-min delayed and 48 had gadoxetate disodium-enhanced 20-min delayed hepatobiliary MR images. The conspicuity of 86 HCCs (mean size, 2.7 cm) was graded visually on a 3-point scale and quantified by liver-to-tumor contrast ratios (LTC). The relative liver parenchymal enhancement (RPE) was measured. For different CPCs, we compared the conspicuity of HCC and RPE between gadodiamide and gadoxetate.

RESULTS

In patients with CPC A, the visual conspicuity and LTC of the 27 HCCs imaged with gadodiamide were significantly lower than those of the 38 HCCs with gadoxetate (P < 0.01, <0.01, respectively). RPE was lower in gadodiamide scans than gadoxetate scans (P < 0.01). Conversely, in patients with CPC B and C, HCCs appeared more frequently as definite hypointensity when imaged with gadodiamide (72.7%, 8/11) than gadoxetate (20%, 2/10, P = 0.03). LTC (mean 18.1 vs. 7.5, P = 0.04) and RPE (mean 75.5 vs. 45.4, P = 0.04) was significantly higher in the gadodiamide than gadoxetate scans.

CONCLUSION

In patients with compromised liver function, hypointensity of HCC is more conspicuous in the gadodiamide delayed phase than the gadoxetate hepatobiliary phase. This likely reflects the high extracellular accumulation of gadodiamide and poor hepatocyte uptake of gadoxetate in patients with compromised liver function.

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.

Arterio-portal shunts in the cirrhotic liver: perfusion computed tomography for distinction of arterialized pseudolesions from hepatocellular carcinoma

OBJECTIVES

To determine perfusion computed tomography (P-CT) findings for distinction of arterial pseudolesions (APL) from hepatocellular carcinoma (HCC) in the cirrhotic liver.

METHODS

32 APL and 21 HCC in 20 cirrhotic patients (15 men; 65 ± 10 years), who underwent P-CT for evaluation of HCC pre- (N = 9) or post- (N = 11) transarterial chemoembolization, were retrospectively included using CT follow-up as the standard of reference. All 53 lesions were qualitatively (visual) and quantitatively (perfusion parameters) analysed according to their shape (wedge, irregular, nodular), location (not-/adjunct to a fistula), arterial liver perfusion (ALP), portal venous liver perfusion (PLP), hepatic perfusion index (HPI). Accuracy for diagnosis of HCC was determined using receiver operating characteristics.

RESULTS

18/32 (56 %) APL were wedge shaped, 10/32 (31 %) irregular and 4/32 (12 %) nodular, while 11/21 (52 %) HCC were nodular or 10/21 (48 %) irregular, but never wedge shaped. Significant difference between APL and HCC was seen for lesion shape in pretreated lesions (P < 0.001), and for PLP and HPI in both pre- and post-treated lesions (all, P < 0.001). Diagnostic accuracy for HCC was best for combined assessment of lesion configuration and PLP showing an area under the curve of 0.901.

CONCLUSION

Combined assessment of lesion configuration and portal venous perfusion derived from P-CT allows best to discriminate APL from HCC with high diagnostic accuracy.

KEY POINTS

• Arterio-portal shunting is common in the cirrhotic liver, especially after local treatment. • Arterial pseudolesions (APL) due to shunting might mimic hepatocellular carcinoma (HCC). • Perfusion-CT allows for qualitative and quantitative assessment of liver lesions. • Lesion configuration fails to discriminate APL from HCC in locally treated patients. • Integration of quantitative perfusion analysis improves accuracy for diagnosis of HCC.

Review of imaging techniques in the diagnosis of hepatocellular carcinoma in patients who require a liver transplant

OBJECTIVES

The aim of the study was to retrospectively compare the diagnostic performance of ultrasound (US), contrast-enhanced multidetector computed tomography (MDCT) and contrast-enhanced MRI in cirrhotic patients who were candidates for liver transplantation.

MATERIALS AND METHODS

A total of 273 consecutive patients with 218 hepatocellular carcinoma (HCC) nodules, who underwent imaging and subsequent transplantation, were examined. Diagnosis of HCC was based on explant correlation of the whole liver. Three different imaging data sets were evaluated: US, MDCT and MRI unenhanced and dynamic phases. Diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive value, with corresponding 95% confidence intervals, were determined. Statistical analysis was performed for all lesions and for two lesion subgroups (≤2 and >2 cm). Preoperative tumour staging was analysed.

RESULTS

Patient sensitivity to US, MDCT and MRI was 80.4, 81.1 and 90.5%, respectively. Specificity was 96.3, 96.2 and 82.1%. Combined US and MDCT improved sensitivity (88%) without significant loss in specificity (95.7%). Imaging tests resulted in accurate tumour staging in 83.4% of the patients. In per-nodule analysis, technique sensitivity was 55.6, 52.4 and 65.9%, respectively. Sensitivity figures improved when the nodule was larger than 2 cm.

CONCLUSION

Combining imaging techniques is a good strategy for pretransplant HCC diagnosis and provides more accurate cancer staging in patients, which is necessary to decide the correct therapeutic approach.

Hepatocellular carcinoma: A comprehensive review

Hepatocellular carcinoma (HCC) is rapidly becoming one of the most prevalent cancers worldwide. With a rising rate, it is a prominent source of mortality. Patients with advanced fibrosis, predominantly cirrhosis and hepatitis B are predisposed to developing HCC. Individuals with chronic hepatitis B and C infections are most commonly afflicted. Different therapeutic options, including liver resection, transplantation, systemic and local therapy, must be tailored to each patient. Liver transplantation offers leading results to achieve a cure. The Milan criteria is acknowledged as the model to classify the individuals that meet requirements to undergo transplantation. Mean survival remains suboptimal because of long waiting times and limited donor organ resources. Recent debates involve expansion of these criteria to create options for patients with HCC to increase overall survival.

Computed tomography and magnetic resonance imaging features of lipid-rich neuroendocrine tumors of the pancreas

AIM: To clarify the computed tomography (CT) and magnetic resonance imaging (MRI) characteristics of lipid-rich pancreatic neuroendocrine tumors (PanNETs).

METHODS: Enhanced CT and MRI performed before pancreatectomy in 29 patients with 34 histologically-confirmed PanNETs was retrospectively reviewed. Tumor attenuation on CT and signal intensities on conventional (T1- and T2-weighted) and chemical shift MRI were qualitatively analyzed and compared alongside adipose differentiation-related protein (ADRP) immunostaining (ADRP-positive: lipid-rich; ADRP-negative: non-lipid-rich) results using Fisher’s exact test or the Mann-Whitney U test. Signal intensity index on chemical shift MRI was quantitatively assessed.

RESULTS: There were 15 lipid-rich PanNETs (44.1%) in 12 patients (41.4%). Tumor attenuation during the early, portal venous, and delayed phases of enhanced CT (P = 0.888, 0.443, and 0.359, respectively) and signal intensities on conventional MRI (P = 0.698 and 0.798, respectively) were not significantly different between lipid-rich and non-lipid-rich PanNETs. Four of the 15 lipid-rich PanNETs exhibited high signal intensity on subtraction chemical shift MRI, and the association of high signal intensity on subtraction imaging with lipid-rich PanNETs was significant (4 of 15 lipid-rich PanNETs, 26.73%, vs 0 of 19 non-lipid-rich PanNETs, 0%, P = 0.029). Lipid-rich PanNETs showed a significantly higher signal intensity index than non-lipid-rich PanNETs (0.6% ± 14.1% vs -10.4% ± 14.4%, P = 0.004). Eight of 15 lipid-rich PanNETs, vs 0 of 19 non-lipid-rich PanNETs, had positive signal intensity index values in concordance with lipid contents.

CONCLUSION: CT contrast enhancement and conventional MR signal intensities are similar in lipid-rich and non-lipid-rich PanNETs. Chemical shift MRI can demonstrate cytoplasmic lipids in PanNETs.

Imaging Techniques for the Diagnosis of Hepatocellular Carcinoma: A Systematic Review and Meta-analysis

BACKGROUND

Several imaging modalities are available for diagnosis of hepatocellular carcinoma (HCC).

PURPOSE

To evaluate the test performance of imaging modalities for HCC.

DATA SOURCES

MEDLINE (1998 to December 2014), the Cochrane Library Database, Scopus, and reference lists.

STUDY SELECTION

Studies on test performance of ultrasonography, computed tomography (CT), or magnetic resonance imaging (MRI).

DATA EXTRACTION

One investigator abstracted data, and a second investigator confirmed them; 2 investigators independently assessed study quality and strength of evidence.

DATA SYNTHESIS

Few studies have evaluated imaging for HCC in surveillance settings. In nonsurveillance settings, sensitivity for detection of HCC lesions was lower for ultrasonography without contrast than for CT or MRI (pooled difference based on direct comparisons, 0.11 to 0.22), and MRI was associated with higher sensitivity than CT (pooled difference, 0.09 [95% CI, 0.07 to 12]). For evaluation of focal liver lesions, there were no clear differences in sensitivity among ultrasonography with contrast, CT, and MRI. Specificity was generally 0.85 or higher across imaging modalities, but this item was not reported in many studies. Factors associated with lower sensitivity included use of an explanted liver reference standard, and smaller or more well-differentiated HCC lesions. For MRI, sensitivity was slightly higher for hepatic-specific than nonspecific contrast agents.

LIMITATIONS

Only English-language articles were included, there was statistical heterogeneity in pooled analyses, and costs were not assessed. Most studies were conducted in Asia and had methodological limitations.

CONCLUSION

CT and MRI are associated with higher sensitivity than ultrasonography without contrast for detection of HCC; sensitivity was higher for MRI than CT. For evaluation of focal liver lesions, the sensitivities of ultrasonography with contrast, CT, and MRI for HCC are similar.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality. (

PROSPERO

CRD42014007016).

Perfusion computed tomography for detection of hepatocellular carcinoma in patients with liver cirrhosis

PURPOSE

To evaluate the diagnostic performance of dynamic perfusion CT (P-CT) for detection of hepatocellular carcinoma (HCC) in the cirrhotic liver.

MATERIALS AND METHODS

Twenty-six cirrhotic patients (19 men, aged 69 ± 10 years) with suspicion of HCC prospectively underwent P-CT of the liver using the 4D spiral-mode (100/80 kV; 150/175mAs/rot) of a dual-source system. Two readers assessed: (1) arterial liver-perfusion (ALP), portal-venous liver-perfusion (PLP) and hepatic perfusion-index (HPI) maps alone; and (2) side-by-side with maximum-intensity-projections of arterial time-points (art-MIP) for detection of HCC using histopathology and imaging follow-up as standard of reference. Another reader quantitatively assessed perfusion maps of detected lesions.

RESULTS

A total of 48 HCCs in 21/26 (81%) patients with a mean size of 20 ± 10 mm were detected by histopathology (9/48, 19%) or imaging follow-up (39/48, 81%). Detection rates (Reader1/Reader2) of HPI maps and side-by-side analysis of HPI combined with arterial MIP were 92/88% and 98/96%, respectively. Positive-predictive values were 63/63% and 68/71%, respectively. A cut-off value of ≥85% HPI and ≥99% HPI yielded a sensitivity and specificity of 100%, respectively, for detection of HCC.

CONCLUSION

P-CT shows a high sensitivity for detection of HCC in the cirrhotic liver. Quantitative assessment has the potential to reduce false-positive findings improving the specificity of HCC diagnosis.

KEY POINTS

• Visual analysis of perfusion maps shows good sensitivity for detection of HCC. • Additional assessment of anatomical arterial MIPs further improves detection rates of HCC. • Quantitative perfusion analysis has the potential to reduce false-positive findings. • In cirrhotic livers, a hepatic-perfusion-index ≥ 9 9% might be specific for HCC.

[Rational imaging of hepatocellular carcinoma. The challenge of multimodal diagnostic criteria]

CLINICAL/METHODICAL ISSUE

Both computed tomography (CT) and magnetic resonance imaging (MRI) constitute the gold standard in radiological imaging of hepatocellular carcinoma (HCC). In cases of typical contrast behavior each modality as a single dynamic technique allows the diagnosis of HCC. There is still a challenge in detection of small HCCs < 2 cm, in differentiating HCC and high-grade dysplasia from other benign liver lesions as well as the evaluation of hypovascular liver lesions in the cirrhotic liver.

PERFORMANCE

Nowadays, both modalities achieve high detection rates of 90-100 % for lesions > 2 cm. Regarding lesions between 1 and 2 cm there is a higher sensitivity for MRI ranging between 80 and 90 % compared to 60-75 % with CT. Besides the multimodal diagnostic criteria, MRI provides significant benefits with the use of hepatobiliary contrast. Especially in combination with diffusion- weighted imaging (DWI) increased sensitivity and diagnostic accuracy compared to CT has been described for lesions sized < 2 cm. Regarding the differentiation from other hepatic nodules in the cirrhotic liver there is strong evidence that the coexistence of arterial enhancement and hypointensity on hepatobiliary imaging is specific for HCC. Moreover, hypointensity on hepatobiliary imaging is associated with a high positive predictive value (PPV) of up to 100 % for the presence of high-grade dysplasia and HCC.

ACHIEVEMENTS

The use of MRI including hepatobiliary imaging and DWI has to be regarded as the best non-invasive imaging modality for the detection of HCC and for the characterization of nodules in patients with liver cirrhosis. In comparison to CT there are benefits regarding detection of small lesions < 2 cm and evaluation of hypovascular liver lesions in the context of the hepatocarcinogenesis including prognostic values of premalignant lesions.

PRACTICAL RECOMMENDATIONS

Both MRI and CT provide a high diagnostic performance in evaluation of HCC in liver cirrhosis. With MRI there are considerable advantages regarding the detection rate and specificity. For daily clinical routine, CT offers a fast, reliable and easy available modality with benefits for patients in reduced general state of health and restricted compliance.

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.

Hepatocellular carcinoma: diagnostic criteria by imaging techniques

Imaging plays a very important role in the diagnosis of HCC. Indeed, in high-risk patients a noninvasive diagnosis can only be obtained by imaging in presence of typical features. These features include arterial enhancement followed by washout during the portal venous and/or delayed phases on CT scan or MRI. This pattern is quite specific and has been endorsed by both Western and Asian diagnostic guidelines. However, its sensitivity is not very high, especially for small lesions. Therefore ancillary signs may be needed to increase the reliability of the diagnosis. Recent hepatobiliary MRI contrast agents seem to be interesting to improve characterization of small nodules in the cirrhotic liver.

Radiological features of hepatocellular carcinoma

Present article is a review of radiological features of hepatocellular carcinoma on various imaging modalities. With the advancement in imaging techniques, biopsy is rarely needed for diagnosis of hepatocellular carcinoma (HCC), unlike other malignancies. Imaging is useful not only for diagnosis but also for surveillance, therapy and assessing response to treatment. The classical and the atypical radiological features of HCC have been described.

Prognostic performance of preoperative gadoxetic acid-enhanced MRI in resectable hepatocellular carcinoma

PURPOSE

To assess the impact of preoperative evaluation by gadoxetic acid-enhanced magnetic resonance imaging (MRI) on early recurrence outcomes after hepatocellular carcinoma (HCC) resection.

MATERIALS AND METHODS

The retrospective study included two groups of Child-Pugh class A patients who underwent curative liver resection for a single HCC; in one group the HCC was identified by dynamic computed tomography (CT) and gadoxetic acid-enhanced MRI (n = 174; MRI group); in the other by dynamic CT only (n = 416; non-MRI group). We compared the two groups with respect to recurrence-free survival after propensity score matching (162 pairs).

RESULTS

In the matched cohorts, disease-free survival rates for overall and intrahepatic recurrence were 92.6% and 91.9% at 1 year and 78.3% and 79.4% at 2 years, respectively, for the MRI group versus 82.7% and 82.7% at 1 year and 67.2% and 70.4% at 2 years, respectively, for the non-MRI group (P < 0.05). Multivariate Cox analyses revealed that the MRI group was independently superior to the non-MRI group in terms of risk of overall and intrahepatic recurrence at 1 and 2 years in the pooled cohort (P < 0.05).

CONCLUSION

Gadoxetic acid-enhanced MRI evaluation is more useful than dynamic CT for identifying good surgical candidates at low risk of early recurrence following hepatic resection for HCC. J. Magn. Reson. Imaging 2015;41:1115-1123. © 2014 Wiley Periodicals, Inc.

Magnetic resonance imaging in cirrhosis: what's new?

Cirrhosis is the main risk factor for the development of hepatocellular carcinoma (HCC). The major causative factors of cirrhosis in the United States and Europe are chronic hepatitis C infection and excessive alcohol consumption with nonalcoholic steatohepatitis emerging as another important risk factor. Magnetic resonance imaging is the most sensitive imaging technique for the diagnosis of HCC, and the sensitivity can be further improved with the use of diffusion-weighted imaging and hepatocyte-specific contrast agents. The combination of arterial phase hyperenhancement, venous or delayed phase hypointensity "washout feature," and capsular enhancement are features highly specific for HCC with reported specificities of 96% and higher. When these features are present in a mass in the cirrhotic liver, confirmatory biopsy to establish the diagnosis of HCC is not necessary. Other tumors, such as cholangiocarcinoma, sometimes occur in the cirrhotic at a much lower rate than HCC and can mimic HCC, as do other benign lesions such as perfusion abnormalities. In this article, we discuss the imaging features of cirrhosis and HCC, the role of magnetic resonance imaging in the diagnosis of HCC and other benign and malignant lesions that occur in the cirrhotic liver, and the issue of nonspecific arterially hyperenhancing nodules often seen in cirrhosis.

Characterization of 1-to 2-cm liver nodules detected on hcc surveillance ultrasound according to the criteria of the American Association for the Study of Liver Disease: is quadriphasic CT necessary?

OBJECTIVE

The purpose of this study was to identify the essential number of phases from multiphasic CT for 1- to 2-cm hepatocellular carcinoma (HCC) on surveillance ultrasound and to compare the results with the American Association for the Study of Liver Disease (AASLD) standard (arterial phase hypervascularity and portal venous phase [PVP] or delayed phase hypovascularity).

MATERIALS AND METHODS

The study included 110 newly detected nodules (1-2 cm; 36 HCC, 74 benign) in 96 patients detected in an HCC surveillance program. Three radiologists prospectively evaluated the attenuation of each nodule relative to the liver on each phase of quadriphasic CT. Univariate and multivariate logistic regression analyses were used to identify parameters associated with HCC. Multiple combinations of phases were compared with the AASLD standard.

RESULTS

Only arterial phase hypervascularity and delayed phase hypovascularity were significantly associated with HCC both on univariate (odds ratio, arterial phase 7.51 [95% CI, 2.79-20.20]; delayed phase, 2.80 [1.14-6.90]) and multivariate analyses (arterial phase, 11.30 [4.30-29.68]; delayed phase, 4.39 [1.20-16.13]). The combination of arterial phase and delayed phase yielded the highest specificity (99%) and sensitivity (57%). There was no significant difference between AASLD standard (sensitivity, 57%; specificity, 98%) versus biphasic (arterial phase hypervascularity and delayed phase hypovascularity: sensitivity, 57%; p = 1 and specificity, 99%; p = 0.32), triphasic (arterial phase hypervascularity and unenhanced or PVP hypovascularity: sensitivity, 53%; p = 0.325 and specificity, 97%; p = 0.32), or quadriphasic combination (arterial phase hypervascularity and unenhanced, PVP or delayed phase hypovascularity: sensitivity, 57%; specificity, 97%), whereas the sensitivity of biphasic arterial phase and PVP was significantly lower (39% vs 57%, p = 0.022).

CONCLUSION

For diagnosing 1- to 2-cm HCC detected on surveillance ultrasound, arterial phase and delayed phase are two essential phases, providing higher sensitivity than the combination of arterial phase and PVP, and equal performance with triphasic and quadriphasic combinations. The biphasic combination of arterial phase and delayed phase may replace quadriphasic CT recommended by AASLD.