Detection of small (≤2 cm) HCC in cirrhotic patients: added value of diffusion MR-imaging

Diagnostic accuracy of apparent diffusion coefficient (ADC) value in differentiating malignant from benign solid liver lesions: a systematic review and meta-analysis

OBJECTIVES

We undertook a systematic review and meta-analysis of the diagnostic performance of mean apparent diffusion coefficient (ADC) values derived by diffusion-weighted (DW)-MRI in the characterization of solid benign and malignant liver lesions, and to assess their value in discriminating these lesions in daily routine practice.

METHODS

A systematic review of PubMed, Embase, Scopus, and Web of Science was conducted to retrieve studies that used ADC values for differentiating solid benign/dysplastic nodules and malignant liver lesions. A bivariate random-effects model with pooled sensitivity and specificity values with 95% CI (confidence interval) was used. This meta-analysis was performed on the per-lesion basis. Summary receiver operating characteristic (SROC) plot and area under curve (AUC) were created.

RESULTS

A total of 14 original articles were retrieved. The combined (95% CI) sensitivity and specificity of mean ADC values for differentiating solid benign from malignant lesions were 78% (67-86%) and 74% (64-81%), respectively. The pooled (95% CI) positive and negative LRs were respectively 3 (2.3-3.8) and 0.3 (0.21-0.43). The DOR (95% CI) was 10 (7-15). The AUC (95% CI) of the SROC plot was 82% (78-85%). Reporting bias was negligible (p value of regression test = 0.36). Mean size of malignant lesions and breathing pattern of MRI were found to be sources of heterogeneity of pooled sensitivity.

CONCLUSION

ADC measurement independently may not be an optimal diagnostic imaging method for differentiating solid malignant from solid benign hepatic lesions. The meta-analysis showed that ADC measurement had moderate diagnostic accuracy for characterizing solid liver lesions. Further prospective and comparative studies with pre-specified ADC thresholds could be performed to investigate the best MRI protocol and ADC threshold for characterizing solid liver lesions.

ADVANCES IN KNOWLEDGE

ADC measurement by DW-MRI does not have a good diagnostic performance to differentiate solid malignant from solid benign lesions. Therefore, we suggest not using ADC values in clinical practice to evaluate solid liver lesions.

A meta-analysis of the added value of diffusion weighted imaging in combination with contrast-enhanced magnetic resonance imaging for the diagnosis of small hepatocellular carcinoma lesser or equal to 2 cm

Diffusion weighted imaging (DWI) has been found to increase the sensitivity in the diagnosis of small hepatocellular carcinoma (HCC), although additional studies are required to confirm its value. The aim of the present study was to explore the diagnostic performance of DWI combined with contrast-enhanced magnetic resonance imaging (MRI) for small HCC by performing a meta-analysis. Literature databases (PubMed, Embase, Web of Science and Cochrane Library databases) were searched to identify studies reporting the sensitivity and specificity of MRI with DWI for the diagnosis of small HCCs. Pooled sensitivity and specificity were generated using a bivariate random effect model. Multilevel mixed-effects logistic regression analysis was used to examine the value of DWI combined with conventional MRI. A total of 837 small HCCs and 545 benign liver lesions from 10 studies were included. The overall sensitivity and specificity of DWI combined with contrast-enhanced MRI was 0.88 (95% CI, 0.80-0.93) and 0.90 (95% CI, 0.81-0.95), respectively. Compared with that in contrast-enhanced MRI, DWI with contrast-enhanced MRI had a significantly higher sensitivity for the diagnosis of small HCC (P=0.01) while there was no significant difference in the specificity (P=0.603). The present meta-analysis suggests that DWI combined with contrast-enhanced MRI may increase the sensitivity, whilst maintaining high specificity for the diagnosis of small HCCs with a diameter ≤2 cm.

Independent risk factors for disease recurrence after surgery in patients with hepatitis B virus-related hepatocellular carcinoma ≤3 cm in diameter

Background

Post-operative recurrence rates are high for hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). This study aimed to explore the factors associated with post-operative 1-year recurrence rate in patients with HBV-related HCC who had a single small primary tumor (≤3 cm in diameter).

Methods

This was a retrospective study of 203 (training cohort) and 64 (validation cohort) patients newly diagnosed with HBV-related HCC who had a single small primary tumor. The first year of post-operative follow-up was examined. Factors potentially associated with HCC recurrence were identified using Cox regression analyses. A model was constructed based on the factors identified and the prognostic value of the model was evaluated using receiver operating characteristic (ROC) curve analysis and calculation of the area under the ROC curve (AUC).

Results

A history of alcoholism and serum levels of α-fetoprotein, total protein and γ-glutamyl transpeptidase (GGT) were independently associated with 1-year recurrence rate after surgery. A predictive model based on these four factors had an AUC of 0.711 (95% confidence interval, 0.643-0.772) in the training cohort and 0.727 (95% confidence interval, 0.601-0.831) in the validation cohort. The 1-year recurrence rate was significantly lower in the low-risk group than in the high-risk group in both the training cohort (17.0% vs. 49.5%, P < 0.001) and the validation cohort (43.2% vs. 74.1%, P = 0.031).

Conclusion

A history of alcoholism and serum levels of α-fetoprotein, total protein and γ-glutamyl transpeptidase were independently associated with post-operative 1-year recurrence rate in patients with HBV-related HCC who had a single small primary tumor (≤3 cm in diameter).

Diagnostic accuracy of Magnetic Resonance Imaging using liver tissue specific contrast agents and contrast enhanced Multi Detector Computed Tomography: A systematic review of diagnostic test in Hepatocellular Carcinoma (HCC)

OBJECTIVES

The aim of this systematic review is to investigate diagnostic accuracy of Magnetic Resonance Imaging (MRI) scans using liver specific tissue contrast media over contrast enhanced Multi Detector CT (MDCT) in diagnoses of Hepatocellular Carcinoma (HCC) in patients with chronic liver disease.

KEY FINDINGS

A total of 8 diagnostic studies were identified and generally considered of high quality. The studies reported sufficient evidence on sensitivity and specificity, which was synthesised and summarised providing an overview of the evidence. Findings indicate that MRI scans using liver specific tissue contrast have a better diagnostic performance compared to contrast enhanced MDCT in diagnostic work-up of HCC in patients with chronic liver disease.

CONCLUSION

The current review identified sufficient high quality studies reporting statistical difference (P < 0.05), to establish the superiority of gadoxetetic acid enhanced MRI for sensitivity and specificity in comparison to MDCT in the diagnosis of HCC in chronic liver disease.

Preoperative detection of malignant liver tumors: Comparison of 3D-T2-weighted sequences with T2-weighted turbo spin-echo and single shot T2 at 1.5 T

PURPOSE

To assess the performances of three-dimensional (3D)-T2-weighted sequences compared to standard T2-weighted turbo spin echo (T2-TSE), T2-half-Fourier acquisition single-shot turbo spin-echo (T2-HASTE), diffusion weighted imaging (DWI) and 3D-T1-weighted VIBE sequences in the preoperative detection of malignant liver tumors.

METHODS

From 2012 to 2015, all patients of our institution undergoing magnetic resonance imaging (MRI) examination for suspected malignant liver tumors were prospectively included. Patients had contrast-enhanced 3D-T1-weighted, DWI, 3D-T2-SPACE, T2-HASTE and T2-TSE sequences. Imaging findings were compared with those obtained at follow-up, surgery and histopathological analysis. Sensitivities for the detection of malignant liver tumors were compared for each sequence using McNemar test. A subgroup analysis was conducted for HCCs. Image artifacts were analyzed and compared using Wilcoxon paired signed rank-test.

RESULTS

Thirty-three patients were included: 13 patients had 40 hepatocellular carcinomas (HCC) and 20 had 54 liver metastases. 3D-T2-weighted sequences had a higher sensitivity than T2-weighted TSE sequences for the detection of malignant liver tumors (79.8% versus 68.1%; P < 0.001). The difference did not reach significance for HCC. T1-weighted VIBE and DWI had a higher sensitivity than T2-weighted sequences. 3D-T2-weighted-SPACE sequences showed significantly less artifacts than T2-weitghted TSE.

CONCLUSION

3D-T2-weighted sequences show very promising performances for the detection of liver malignant tumors compared to T2-weighted TSE sequences.

MRI of Small Hepatocellular Carcinoma: Typical Features Are Less Frequent Below a Size Cutoff of 1.5 cm

OBJECTIVE

The purposes of this study were to analyze MRI features of small hepatocellular carcinomas (HCCs) on the basis of size and to evaluate the difference in frequency of typical radiologic hallmarks of HCC (arterial enhancement and washout) according to the tumor size.

MATERIALS AND METHODS

Enrolled were 86 patients with 110 HCCs 3 cm or smaller who underwent surgical resection or transplantation. Two radiologists reviewed gadoxetic acid-enhanced MRI features for signal intensity of T2-weighted and T1-weighted imaging, diffusion restriction, presence of arterial enhancement, washout on portal and transitional phases, and signal intensity on the hepatobiliary phase. ROC curve analysis was performed to determine the optimal HCC cutoff size for radiologic hallmarks of HCC. Tumors were divided into two groups by cutoff size, and the frequencies of MRI features were assessed.

RESULTS

On ROC analysis, the optimal cutoff for radiologic hallmarks of HCC was 1.5 cm in independent and consensus reviews by two radiologists. HCCs smaller than 1.5 cm showed typical finding of HCC less frequently than HCCs 1.5 cm or larger in diameter. In subgroup analyses, HCCs with diameters between 1 and 1.5 cm showed similar MRI findings to HCCs with diameters 1 cm or less but significantly different findings compared with HCCs with diameters from 1.5 to 2 cm and 2-3 cm.

CONCLUSION

HCCs smaller than 1.5 cm in size less frequently showed MRI findings seen typically in larger HCCs. Therefore, small HCCs are harder to detect with certainty not only because of small size but also because of the lower frequency of typical MRI findings.

Qualitative analysis of small (≤2 cm) regenerative nodules, dysplastic nodules and well-differentiated HCCs with gadoxetic acid MRI

Background

The characterization of small lesions in cirrhotic patients is extremely difficult due to the overlap of imaging features among different entities in the step-way of the hepatocarcinogenesis. The aim of our study was to evaluate the role of gadoxetic-acid MRI in the differentiation of small (≤2 cm) well-differentiated hepatocellular carcinomas from regenerative and dysplastic nodules.

Methods

Seventy-three cirrhotic patients, with 118 focal liver lesions (≤2 cm) were prospectively recruited. MRI examination was performed with a 3T magnet and the study protocol included T1 - and T2-weighted pre-contrast sequences and T1 -weighted gadoxetic-acid enhanced post-contrast sequences obtained during the arterial, venous, late dynamic and hepatobiliary phases. All lesions were pathologically confirmed. Two radiologists blinded to clinical and pathological information evaluated two imaging datasets; another radiologist analysed the signal intensity characteristics of each lesion. Sensitivity, specificity and diagnostic accuracy were considered for statistical analysis.

Results

Good agreement was reported between the two readers (κ 0.70). Both readers reported a significantly improved sensitivity (57.7 and 66.2 vs 74.6 and 83.1) and diagnostic accuracy (0.717 and 0.778 vs 0.843 and 0.901) with the adjunction of the hepatobiliary phase 57.7 vs 74.6 and 66.2 vs 83.1 (p ≤ 0.04).

Conclusions

Gadoxetic-acid MRI is a reliable tool for the characterization of HCC and lesions at high risk to further develop.

Magnetic resonance imaging of the cirrhotic liver in the era of gadoxetic acid

Gadoxetic acid improves detection and characterization of focal liver lesions in cirrhotic patients and can estimate liver function in patients undergoing liver resection. The purpose of this article is to describe the optimal gadoxetic acid study protocol for the liver, the unique characteristics of gadoxetic acid, the differences between gadoxetic acid and extra-cellular gadolium chelates, and the differences in phases of enhancement between cirrhotic and normal liver using gadoxetic acid. We also discuss how to obtain and recognize an adequate hepatobiliary phase.

Combined Application of Gadoxetic Acid Disodium-Enhanced Magnetic Resonance Imaging (MRI) and Diffusion-Weighted Imaging (DWI) in the Diagnosis of Chronic Liver Disease-Induced Hepatocellular Carcinoma: A Meta-Analysis

Objective

Gadoxetic acid disodium (Gd-EOB-DTPA) is a magnetic resonance imaging (MRI) contrast agent to target the liver cells with normal function. In clinical practice, the Gd-EOB-DTPA produces high quality hepatocyte specific image 20 minutes after intravenous injection, so DWI sequence is often performed after the conventional dynamic scanning. However, there are still some disputes about whether DWI sequence will provide more effective diagnostic information in clinical practice. This study aimed to explore the diagnostic value of combining Gd-EOB-DTPA-enhanced MRI and DWI in the detection of hepatocellular carcinoma (HCC) in patients with chronic liver disease.

Methods

A systematic literature search was performed in the PubMed and Cochrane library database up to March 2015. The quality assessment of diagnostic accuracy studies (QUADAS) was used to evaluate the quality of studies. Heterogeneous test on the included literature was performed by using the software Review Manager 5.3. The MetaDiSc 1.4 software was used to calculate the pooled sensitivity, specificity, positive likelihood ratio and negative likelihood ratio; meanwhile the summary receiver operating characteristics (SROC) curve was drawn to compare the diagnostic performance.

Results

A total of 13 literatures were included in this study. In 8 literatures regarding HCC diagnosis based on Gd-EOB-DTPA-enhanced MRI, the pooled sensitivity: 0.90 (95% confidence interval (CI): 0.88–0.93); specificity: 0.89 (95% CI: 0.85–0.92); positive likelihood ratio: 8.60 (95% CI: 6.20–11.92); negative likelihood ratio: 0.10 (95% CI: 0.08–0.14) were obtained. The area under curve (AUC) and Q values were 0.96 and 0.90, respectively. In 5 literatures relating to HCC diagnosis by combination of Gd-EOB-DTPA-enhanced MRI and DWI sequence, the pooled sensitivity: 0.88 (95% CI: 0.85–0.91), specificity: 0.96 (0.94–0.97), positive likelihood ratio: 19.63 (12.77–30.16), negative likelihood ratio: 0.10 (0.07–0.14) were obtained. The AUC value was 0.9833 and Q value was 0.9436. The AUC value of comprehensive evaluation method was significantly higher than that of Gd-EOB-DTPA-enhanced MRI alone(P<0.05).

Conclusion

Combination of Gd-EOB-DTPA-enhanced MRI and DWI sequence significantly improves in both the diagnostic accuracy and specificity of chronic liver disease-associated HCC.

The Diagnostic Performance of Dynamic Contrast-enhanced MR Imaging for Detection of Small Hepatocellular Carcinoma Measuring Up to 2 cm: A Meta-Analysis

PURPOSE

To determine the performance of dynamic contrast material-enhanced magnetic resonance (MR) imaging in the diagnosis of small (≤2-cm) hepatocellular carcinoma (HCC) and to identify factors that influence this performance.

MATERIALS AND METHODS

Medline and Embase databases were searched for studies performed from January 2000 to March 2014 in which the performance of MR imaging was reported for the detection of HCC up to 2 cm on either a lesion- or patient-based level, with sufficient data to construct 2 × 2 contingency tables. Diagnostic performance was quantitatively pooled for all studies by using a bivariate random-effects model with exploration involving subgroup analysis, meta-regression, and determination of study heterogeneity.

RESULTS

Twenty-two studies with 1387 small HCC lesions in 1908 patients met inclusion criteria. Heterogeneity was higher for sensitivity (range, 30%-99%) than specificity (range, 61%-100%). Overall sensitivity was 78% (95% confidence interval [CI]: 68%, 85%; I(2) = 89%), and overall specificity was 92% (95% CI: 88%, 95%; I(2) = 69%). The primary potential source of bias was use of explant as the reference standard in only 13% of studies, although lower sensitivity in such studies was not significant (59% vs 80%, P = .165). Sensitivities were significantly higher for studies that originated from Asia compared with those that originated elsewhere (89% vs 71%, P = .028), those performed with hepatobiliary phase imaging compared with those without (87% vs 65%, respectively; P = .004), and those in which gadoxetate disodium was used versus an extracellular agent (92% vs 67%, P ≤ .001). Specificity was not significantly different between subgroups (P ≥ .122). At pairwise meta-regression analysis with either study origin from Asia or performance of hepatobiliary phase imaging, only gadoxetate disodium contrast agent showed significant independent association with higher sensitivity (P = .002-.007).

CONCLUSION

Results of this meta-analysis suggest that dynamic contrast-enhanced MR imaging has moderate sensitivity and excellent specificity in the detection of HCC up to 2 cm. Gadoxetate disodium contrast agent showed the strongest association with increased sensitivity.

Role of diffusion-weighted imaging, apparent diffusion coefficient and correlation with hepatobiliary phase findings in the differentiation of hepatocellular carcinoma from dysplastic nodules in cirrhotic liver

OBJECTIVES

To investigate the utility of diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC) and the correlation with hepatobiliary phase (delayed phase imaging, DPI) findings in the differentiation of cirrhotic hepatocellular nodules.

METHODS

Forty-three patients with 53 pathology-proven nodules (29 hepatocellular carcinomas (HCCs), 13 high-grade (HGDNs) and 11 low-grade dysplastic nodules (LGDNs); mean size 2.17 cm, range 1-4 cm), who underwent liver MRI with DWI and DPI sequences, were retrospectively reviewed. Lesions were classified as hypointense, isointense, or hyperintense relative to the adjacent liver parenchyma. ADC of each nodule, of the surrounding parenchyma, and lesion-to-liver ratio were calculated.

RESULTS

Hyperintensity versus iso/hypointensity on DWI, hypointensity versus iso/hyperintensity on DPI, and the mean lesion-to-liver ratio showed a statistically significant difference both between HCCs versus DNs and between "HCCs + HGDNs" versus LGDNs (p < 0.05); sensitivity, specificity, and accuracy for the diagnosis of "HCCs + HGDNs" were 96.8 %, 100 %, 97.4 % respectively when combining hyperintensity on DWI and hypointensity on DPI, and 90.9 %, 81.0 %, 83.6 % respectively when lesion-to-liver ratio was <0.95.

CONCLUSIONS

Hyperintensity on DWI, especially in association with hypointensity on DPI, and low lesion-to-liver ratios should raise the suspicion of HCC, or at least of HGDN, thus helping the characterization of atypically enhancing lesions.

KEY POINTS

• Usefulness of DWI and ADC is shown in differential diagnosis of cirrhotic nodules. • Correlation of DWI with DPI improves differential diagnosis of cirrhotic nodules. • Characterization of atypically enhancing lesions becomes more confident.

Impact of 3D Rotational Angiography on Liver Embolization Procedures: Review of Technique and Applications

In the last years, the interest into interventional applications of C-arm cone-beam CT (CBCT) progressively raised, widening its clinical application from the original field of interventional neuroradiology to the field of peripheral procedures. Liver embolization procedures, due to their complexity and potential treatment-related life-threatening complications, represent one of the main clinical applications of this novel angiographic technique. CBCT has been demonstrated to render procedures safer and technically easier, and to predict outcome as well as to avoid major complications in different treatment scenarios (trans-arterial embolization, trans-arterial chemoembolization, selective internal radiation therapy, percutaneous portal vein embolization). This review summarizes all technical, dosimetric and procedural aspects of CBCT techniques, underlying all its potential clinical advantages in the field of liver embolization procedures. Moreover, the paper provides all the instructions to obtain the best diagnostic performance out of this novel angiographic technique.