Preoperative evaluation of the histological grade of hepatocellular carcinoma with diffusion-weighted imaging: a meta-analysis

Apparent diffusion coefficient and tissue stiffness are associated with different tumor microenvironment features of hepatocellular carcinoma

OBJECTIVES

To investigate associations between tissue diffusion, stiffness, and different tumor microenvironment features in resected hepatocellular carcinoma (HCC).

METHODS

Seventy-two patients were prospectively included for preoperative magnetic resonance (MR) diffusion-weighted imaging and MR elastography examination. The mean apparent diffusion coefficient (ADC) and stiffness value were measured on the central three slices of the tumor and peri-tumor area. Cell density, tumor-stroma ratio (TSR), lymphocyte-rich HCC (LR-HCC), and CD8 + T cell infiltration were estimated in resected tumors. The interobserver agreement of MRI measurements and subjective pathological evaluation was assessed. Variables influencing ADC and stiffness were screened with univariate analyses, and then identified with multivariable linear regression. The potential relationship between explored imaging biomarkers and histopathological features was assessed with linear regression after adjustment for other influencing factors.

RESULTS

Seventy-two patients (male/female: 59/13, mean age: 56 ± 10.2 years) were included for analysis. Inter-reader agreement was good or excellent regarding MRI measurements and histopathological evaluation. No correlation between tumor ADC and tumor stiffness was found. Multivariable linear regression confirmed that cell density was the only factor associated with tumor ADC (Estimate = -0.03, p = 0.006), and tumor-stroma ratio was the only factor associated with tumor stiffness (Estimate = -0.18, p = 0.03). After adjustment for fibrosis stage (Estimate = 0.43, p < 0.001) and age (Estimate = 0.04, p < 0.001) in the multivariate linear regression, intra-tumoral CD8 + T cell infiltration remained a significant factor associated with peri-tumor stiffness (Estimate = 0.63, p = 0.02).

CONCLUSIONS

Tumor ADC surpasses tumor stiffness as a biomarker of cellularity. Tumor stiffness is associated with tumor-stroma ratio and peri-tumor stiffness might be an imaging biomarker of intra-tumoral immune microenvironment.

CLINICAL RELEVANCE STATEMENT

Tissue stiffness could potentially serve as an imaging biomarker of the intra-tumoral immune microenvironment of hepatocellular carcinoma and aid in patient selection for immunotherapy.

KEY POINTS

Apparent diffusion coefficient reflects cellularity of hepatocellular carcinoma. Tumor stiffness reflects tumor-stroma ratio of hepatocellular carcinoma and is associated with tumor-infiltrating lymphocytes. Tumor and peri-tumor stiffness might serve as imaging biomarkers of intra-tumoral immune microenvironment.

Diagnostic evaluation and ablation treatments assessment in hepatocellular carcinoma

This article provides an overview of diagnostic evaluation and ablation treatment assessment in Hepatocellular Carcinoma (HCC). Only studies, in the English language from January 2010 to January 202, evaluating the diagnostic tools and assessment of ablative therapies in HCC patients were included. We found 173 clinical studies that satisfied the inclusion criteria.HCC may be noninvasively diagnosed by imaging findings. Multiphase contrast-enhanced imaging is necessary to assess HCC. Intravenous extracellular contrast agents are used for CT, while the agents used for MRI may be extracellular or hepatobiliary. Both gadoxetate disodium and gadobenate dimeglumine may be used in hepatobiliary phase imaging. For treatment-naive patients undergoing CT, unenhanced imaging is optional; however, it is required in the post treatment setting for CT and all MRI studies. Late arterial phase is strongly preferred over early arterial phase. The choice of modality (CT, US/CEUS or MRI) and MRI contrast agent (extracelllar or hepatobiliary) depends on patient, institutional, and regional factors. MRI allows to link morfological and functional data in the HCC evaluation. Also, Radiomics is an emerging field in the assessment of HCC patients.Postablation imaging is necessary to assess the treatment results, to monitor evolution of the ablated tissue over time, and to evaluate for complications. Post- thermal treatments, imaging should be performed at regularly scheduled intervals to assess treatment response and to evaluate for new lesions and potential complications.

A study of the correlations between IVIM-DWI parameters and the histologic differentiation of hepatocellular carcinoma

The present study aimed to investigate the value of intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) in the preoperative prediction of the histologic differentiation of hepatocellular carcinoma (HCC). Seventy HCC patients were scanned with a 3.0 T magnetic resonance scanner. The values of apparent diffusion coefficient (ADC), slow apparent diffusion coefficient (D), fast apparent diffusion coefficient (D*), and the fraction of the fast apparent diffusion coefficient (f) were measured. Analysis of variance was used to compare the differences in parameters between groups with different degrees of histologic differentiation. p < 0.05 was considered statistically significant. Receiver operating characteristic (ROC) curves were used to analyse the efficacy of IVIM-DWI parameters for predicting the histologic differentiation of HCC. The ADC and D values for well, moderately and poorly differentiated HCC were 1.35 ± 0.17 × 10^-3 mm²/s, 1.16 ± 0.17 × 10^-3 mm²/s, 0.98 ± 0.21 × 10^-3 mm²/s, and 1.06 ± 0.15 × 10^-3 mm²/s, 0.88 ± 0.16 × 10^-3 mm²/s, 0.76 ± 0.18 × 10^-3 mm²/s, respectively, and all differences were significant. The D* and f values of the three groups were 32.87 ± 14.70 × 10^-3 mm²/s, 41.68 ± 17.90 × 10^-3 mm²/s, 34.54 ± 18.60 × 10^-3 mm²/s and 0.22 ± 0.07, 0.23 ± 0.08, 0.18 ± 0.07, respectively, with no significant difference. When the cut-off values of ADC and D were 1.25 × 10^-3 mm²/s and 0.97 × 10^-3 mm²/s, respectively, their diagnostic sensitivities and specificities for distinguishing well differentiated HCC from moderately differentiated and poorly differentiated HCC were 73.3%, 85.5%, 86.7%, and 78.2%, and their areas under the ROC curve were 0.821 and 0.841, respectively. ADC and D values can be used preoperatively to predict the degree of histologic differentiation in HCC, and the D value has better diagnostic value.

A study of the correlations between IVIM-DWI parameters and the histologic differentiation of hepatocellular carcinoma

The present study aimed to investigate the value of intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) in the preoperative prediction of the histologic differentiation of hepatocellular carcinoma (HCC). Seventy HCC patients were scanned with a 3.0 T magnetic resonance scanner. The values of apparent diffusion coefficient (ADC), slow apparent diffusion coefficient (D), fast apparent diffusion coefficient (D*), and the fraction of the fast apparent diffusion coefficient (f) were measured. Analysis of variance was used to compare the differences in parameters between groups with different degrees of histologic differentiation. p < 0.05 was considered statistically significant. Receiver operating characteristic (ROC) curves were used to analyse the efficacy of IVIM-DWI parameters for predicting the histologic differentiation of HCC. The ADC and D values for well, moderately and poorly differentiated HCC were 1.35 ± 0.17 × 10⁻³ mm²/s, 1.16 ± 0.17 × 10⁻³ mm²/s, 0.98 ± 0.21 × 10⁻³ mm²/s, and 1.06 ± 0.15 × 10⁻³ mm²/s, 0.88 ± 0.16 × 10⁻³ mm²/s, 0.76 ± 0.18 × 10⁻³ mm²/s, respectively, and all differences were significant. The D* and f values of the three groups were 32.87 ± 14.70 × 10⁻³ mm²/s, 41.68 ± 17.90 × 10⁻³ mm²/s, 34.54 ± 18.60 × 10⁻³ mm²/s and 0.22 ± 0.07, 0.23 ± 0.08, 0.18 ± 0.07, respectively, with no significant difference. When the cut-off values of ADC and D were 1.25 × 10⁻³ mm²/s and 0.97 × 10⁻³ mm²/s, respectively, their diagnostic sensitivities and specificities for distinguishing well differentiated HCC from moderately differentiated and poorly differentiated HCC were 73.3%, 85.5%, 86.7%, and 78.2%, and their areas under the ROC curve were 0.821 and 0.841, respectively. ADC and D values can be used preoperatively to predict the degree of histologic differentiation in HCC, and the D value has better diagnostic value.

Diagnostic accuracy of quantitative diffusion parameters in the pathological grading of hepatocellular carcinoma: A meta-analysis

BACKGROUND

Accurate preoperative assessment of the pathological grade of hepatocellular carcinoma (HCC) could greatly benefit prognostic predictions.

PURPOSE

To assess and compare the diagnostic accuracy of the apparent diffusion coefficient (ADC) and tissue diffusivity (D) for the noninvasive pathological grading of HCC.

STUDY TYPE

Meta-analysis.

DATA SOURCES

PubMed/Medline, EMBASE, the Web of Science, and the Cochrane Library were searched to find related original articles published up to May 30, 2019.

FIELD STRENGTH/SEQUENCE

Diffusion-weighted imaging (DWI) and/or intravoxel incoherent motion (IVIM) were performed with a 1.5T or 3.0T scanner.

ASSESSMENT

The Quality Assessment of Diagnostic Accuracy Studies 2 tool was used to assess the methodologic quality.

STATISTICAL TESTS

The bivariate random-effects model was used to obtain the pooled sensitivity and specificity, and the area under summary receiver operating characteristic curve (AUROC) was obtained. Subgroup analyses were performed.

RESULTS

A total of 16 original articles (1428 HCCs) were included. Most studies had a low to unclear risk of bias and minimal concerns regarding applicability. For the discrimination of well-differentiated HCCs, the pooled sensitivity and specificity of the ADC value were 85% and 92%, respectively. For the discrimination of poorly differentiated HCCs, the pooled sensitivity and specificity of the ADC value and D were 84% and 80%, and 92% and 77%, respectively. The summary AUROC of D (0.94) was significantly higher than that of ADC (0.89) (z = -2.718, P = 0.007). The subgroup analyses identified three covariates including size, number of included lesions in the studies, and blindness to the reference standard as possible sources of heterogeneity.

DATA CONCLUSION

This meta-analysis showed that the ADC and D values had a high to excellent accuracy for the noninvasive pathological grading of HCCs and that the D value was superior to the ADC value for discriminating poorly differentiated HCCs.

LEVEL OF EVIDENCE

3 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:1581-1593.

Microvascular invasion and grading in hepatocellular carcinoma: correlation with major and ancillary features according to LIRADS

PURPOSE

To assess major and ancillary parameters that could be correlated with Microvascular Invasion (MIV) and with histologic grade of HCC.

MATERIALS AND METHODS

In this retrospective study, we assessed 62 patients (14 women-48 men; mean age, 63 years; range 38-80 years) that underwent hepatic resection for HCC. All patients were subject to Multidetector computed tomography (MDCT); 40 to Magnetic Resonance (MR) study. The radiologist assessed major and ancillary features according to LIRADS (v. 2018) and reported any radiological accessory findings if detected.

RESULTS

No major feature showed statistically significant differences and correlation with grading. Mean ADC value was correlated with grading and with MIV status. No major feature was correlated to MIV; progressive contrast enhancement and satellite nodules showed statistically different percentages with respect to the presence of MIV, so as at the monovariate correlation analysis, satellite nodules were correlated with the presence of MIV. At multivariate regression analysis, no factor proved to be strong predictors of grading while progressive contrast enhancement and satellite nodules were significantly associated with the MIV.

CONCLUSION

Mean ADC value is correlated to HCC grading and MIV status. Progressive contrast enhancement and the presence of satellite nodules are correlated to MIV status.

Diffusion-weighted imaging of hepatocellular carcinoma before and after transarterial chemoembolization: role in survival prediction and response evaluation

BACKGROUND

Survival outcomes of patients with hepatocellular carcinoma (HCC) treated with transarterial chemoembolization (TACE) are heterogeneous. Measuring the apparent diffusion coefficient (ADC) using diffusion-weighted imaging (DWI) may improve overall survival prediction.

AIM

To assess the value of measuring the ADC before and after TACE in predicting overall survival.

METHODS

A retrospective analysis was performed in HCC patients treated with TACE at a tertiary referral center between 2008 and 2017. The ADC values and changes in ADC value (ΔADC) of HCC lesions (≥ 1 cm) and liver parenchyma were assessed by DWI ≤ 3 months before and after first TACE. Pre- and post-TACE ADC values were compared with tumor response according to mRECIST and correlated with overall survival (OS) in a univariable and multivariable Cox-regression analysis.

RESULTS

A total of 89 patients were included, mostly Child-Pugh A (85%) and BCLC stage B (53%) with a median OS of 21.7 months (95% CI 17.6-25.9). Tumor ADC increased from 1081 mm²/s before (IQR 964-1225) to 1328 mm²/s (IQR 1197-1560) after TACE (p < 0.001). Responders according to mRECIST showed a higher ΔADC after first TACE than non-responders (26 vs. 14%, p = 0.048). Pre-TACE ADC and ΔADC were not significantly associated with OS in both univariable and multivariable analysis, whereas response according to mRECIST remained an independent predictor of OS.

CONCLUSION

mRECIST was confirmed as an independent prognostic factor of OS, but pre- or post-TACE ADC measurements were not. Response according to mRECIST was associated with a higher increase in ADC than non-response.

Histopathological characteristics of needle core biopsy and surgical specimens from patients with solitary hepatocellular carcinoma or intrahepatic cholangiocarcinoma

BACKGROUND

Pathological manifestations of hepatic tumours are often associated with prognosis. Although surgical specimens (SS) can provide more information, currently, pre-treatment needle core biopsy (NCB) is increasingly showing important value in understanding the nature of liver tumors and even in diagnosis and treatment decisions. However, the concordance of the clinicopathological characteristics and immunohistochemical (IHC) staining between NCB and SS from patients with hepatic tumours were less concerned.

AIM

To introduce a more accurate method for interpreting the IHC staining results in order to improve the diagnostic value of hepatic malignancy in NCB samples.

METHOD

A total of 208 patients who underwent both preoperative NCB and surgical resection for hepatocellular carcinoma (HCC) or intrahepatic cholangiocarcinoma (ICC) between 2008 and 2015 were enrolled in this study. The expression of CK19, GPC3, and HepPar1 were detected by IHC staining. Clinicopathological, NCB, and surgical data were collected and analysed using χ² and kappa statistics.

RESULTS

Morphologically, the presence of compact tumour nests or a cord-like structure in NCB was considered the primary cause of misdiagnosis of HCC from ICC. The kappa statistic showed a moderate agreement in histomorphology (k = 0.504) and histological grade (k = 0.488) between NCB and SS of the tumours. A 4-tier (+++, ++, +, and -) scoring scheme that emphasized the focal neoplastic cell immunoreactivity of tumour cells revealed perfect concordance of CK19, GPC3 and HepPar1 between NCB and SS (k = 0.717; k = 0.768; k = 0.633). Furthermore, with the aid of a binary classification derived from the 4-tier score, a high concordance was achieved in interpreting the IHC staining of the three markers between NCB and final SS (k = 0.931; k = 0.907; k = 0.803), increasing the accuracy of NCB diagnosis C (k = 0.987; area under the curve = 0.997, 95%CI: 0.990-1.000; P < 0.001).

CONCLUSION

These findings imply that reasonable interpretation of IHC results in NCB is vital for improving the accuracy of tumour diagnosis. The simplified binary classification provides an easy and applicable approach.

Diffusion kurtosis imaging (DKI) of hepatocellular carcinoma: correlation with microvascular invasion and histologic grade

BACKGROUND

The aim of this study was to prospectively evaluate the diagnostic efficacy of diffusion kurtosis imaging (DKI) in predicting microvascular invasion (MVI) and histologic grade of hepatocellular carcinoma (HCC) with comparison to the conventional diffusion-weighted imaging (DWI).

METHODS

This prospective study was approved by the Institutional Review Board, and written informed consent was obtained from all patients. From September 2015 to January 2017, 74 consecutive HCC patients were enrolled in this study. Preoperative magnetic resonance imaging including DKI protocol was performed, and patients were followed up for at least one year after surgery. Diffusion parameters including the mean corrected apparent diffusion coefficient (MD), mean apparent kurtosis coefficient (MK), and apparent diffusion coefficient (ADC) were calculated. Differences of diffusion parameters among different histopathological groups were compared. For parameters that were significantly different between pathological groups, receiver operating characteristics (ROC) curve analyses were performed to evaluate the diagnostic efficiency for identifying MVI and predicting high-grade HCC. Univariate and multivariate logistic regression analyses were used to evaluate the relative value of clinical and laboratory variables and diffusion parameters as risk factors for early recurrence (≤1 year).

RESULTS

Among all the studied diffusion parameters, only MK differed significantly between the MVI-positive and MVI-negative group (0.91±0.10 vs. 0.82±0.09, P<0.001), and showed moderate diagnostic efficacy (AUC =0.77) for identifying MVI. High-grade HCCs showed significantly higher MK values (0.93±0.10 vs. 0.82±0.09, P<0.001), along with MD (1.34±0.18 vs. 1.54±0.22, P<0.001) and ADC values (1.17±0.15 vs. 1.30±0.16, P=0.001) than low-grade HCCs. For differentiating high-grade from low-grade HCCs, MK demonstrated a higher area under the ROC curve (AUC) and significantly higher specificity than MD and ADC (AUC =0.81 vs. 0.76 and 0.74; specificity =82.2% vs. 60.0% and 60.0%, P=0.02). In addition, higher MK (OR =5.700, P=0.002) and Barcelona Clinic Liver Cancer (BCLC) stage C (OR =6.329, P=0.005) were independent risk factors for early HCC recurrence.

CONCLUSIONS

DKI-derived MK values outperformed conventional ADC values for predicting MVI and histologic grade of HCC, and are associated with increased risk of early tumor recurrence.

The current role and future prospectives of functional parameters by diffusion weighted imaging in the assessment of histologic grade of HCC

Hepatocellular carcinoma (HCC) is one of the most common human solid malignancies worldwide. Although the MRI is the technique that is best adapted to characterize HCC, there is not an agreement regarding the study protocol and even what the role of Diffusion-weighted imaging (DWI). The possibility that imaging study can correlate to histologic grade to selecting the therapeutic strategy would be valuable in helping to direct the proper management of HCC. Apparent Diffusion Coefficient (ADC) and IVIM-derived perfusion fraction (fp) and tissue diffusivity (Dt) values of HCC showed significantly better diagnostic performance in differentiating high-grade HCC from low-grade HCC, and significant correlation was observed between ADC, fp, Dt and histological grade.

Apparent diffusion coefficient of hepatocellular carcinoma on diffusion-weighted imaging: Histopathologic tumor grade versus arterial vascularity during dynamic magnetic resonance imaging

Objectives

Apparent diffusion coefficient (ADC) has been suggested to reflect the tumor grades of hepatocellular carcinomas (HCCs); i.e., it can be used as a biomarker to predict the patients’ prognosis. To verify its feasibility as a biomarker, the present study sought to determine how the ADC values of HCC are affected by a tumor’s histopathologic grade and arterial vascularity.

Materials and methods

From 131 consecutive patients, 141 surgically resected HCCs (16 well-differentiated [wd-HCCs], 83 moderately-differentiated [md-HCCs], and 42 poorly-differentiated HCCs [pd-HCCs]) were subjected to a comparison of the tumors’ arterial vascularity (non-, slightly-, or markedly-hypervascular) determined on dynamic magnetic resonance imaging (MRI) and the ADC was measured retrospectively.

Results

The pd-HCCs (1.05±0.16 × 10⁻³ mm²/s) had a significantly lower ADC than md-HCCs (1.16±0.21 × 10⁻³ mm²/s; p = 0.010), but there was no significant difference compared to wd-HCCs (1.11±0.18 × 10⁻³ mm²/s; p = 0.968). The mean ADC was significantly higher in markedly hypervascular lesions (1.20±0.20 × 10⁻³ mm²/s) than in nonhypervascular lesions (0.95±0.14 × 10⁻³mm²/s; p<0.001) or slightly hypervascular lesions (1.04±0.15 × 10⁻³mm²/s; p<0.001). The ADC values and arterial vascularity were significantly correlated in wd-HCCs (p = 0.005) and md-HCCs (p<0.001). The mean ADC of pd-HCCs was significantly lower than those of other lesions, even in the markedly hypervascular lesion subgroup (p = 0.020).

Conclusion

Although pd-HCC constantly shows low ADCs regardless of arterial vascularities, ADCs cannot stably stratify histopathologic tumor grades due to the variable features of wd-HCCs; and the ADC should be used with caution as a tumor biomarker of HCC.

Prediction of high-stage liver fibrosis using ADC value on diffusion-weighted imaging and quantitative enhancement ratio at the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI at 1.5 T

Background Recently, diffusion-weighted imaging (DWI) and quantitative enhancement ratio measured at the hepatobiliary phase (HBP) of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) has been established as an effective method for evaluating liver fibrosis. Purpose To evaluate which is a more favorable surrogate marker in predicting high-stage liver fibrosis, apparently diffusion coefficient (ADC) value or quantitative enhancement ratio measured on HBP. Material and Methods Eighty-three patients with 99 surgically resected hepatic lesions were enrolled in this study. DWI was performed with b-values of 100 and 800 s/mm². Regions of interest were set on ADC map, and the HBP of Gd-EOB-DTPA-enhanced MRI, to calculate ADC value, liver-to-muscle ratio (LMR), liver-to-spleen ratio (LSR), and contrast enhancement index (CEI) of liver. We compared these parameters between low-stage fibrosis (F0, F1, and F2) and high-stage fibrosis (F3 and F4). Receiver operating characteristic analysis was performed to compare the diagnostic performance when distinguishing low-stage fibrosis from high-stage fibrosis. Results LMR and CEI were significantly lower at high-stage fibrosis than at the low stage ( P < 0.01 and P = 0.04, respectively), whereas LSR did not show a significant difference ( P = 0.053). No significant difference was observed in diagnostic performance between LMR and CEI ( P = 0.185). The best sensitivity and specificity, when an LMR of 2.80 or higher was considered to be low-stage fibrosis, were 82.4% and 75.6%, respectively. ADC value showed no significant differences among fibrosis grades ( P = 0.320). Conclusion LMR and CEI were both adequate surrogate parameters to distinguish high-stage fibrosis from low-stage fibrosis.

Intravoxel incoherent motion (IVIM) in diffusion-weighted imaging (DWI) for Hepatocellular carcinoma: correlation with histologic grade

Purpose

To assess the correlation between DWI diffusion parameters obtained using Intravoxel Incoherent Motion Method (IVIM) and histological grade of Hepatocellular carcinoma (HCC).

Results

According to Edmondson-Steiner grade lesions were classified with grade 1 (14), grade 2 (30), grade 3 (18), and grade 4 (0). Apparent Diffusion Coefficient (ADC), perfusion fraction (fp), tissue diffusion coefficient (Dt) median values were statistically different in HCC groups with 1, 2, 3 histological grade (p<0.001). A significant correlation was reported between ADC, fp, Dt and histologic grade respectively of 0.687, 0.737 and 0.674. Receiver operating characteristic (ROC) analysis demonstrated that an ADC of 2.11×10-3 mm2/sec, an fp of 47.33% and an Dt of 0.94×10-3 mm²/sec were the optimal cutoff values to differentiate high histological grade (3) versus low histological grade (1-2), with a sensitivity and specificity for ADC of 100% and 100%, for fp of 100% and 89%, for Dt of 100% and 74%, respectively.

Material and Methods

A retrospective approved study was performed including 34 patients with 62 HCCs. IVIM was performed to obtain ADC, fp, pseudo-diffusion coefficient (Dp), Dt coefficients. Kruskal Wallis, Spearman Correlation Coefficient, ROC analysis were performed.

Conclusions

ADC and IVIM-derived fp showed significantly better diagnostic performance in differentiating high-grade from low-grade HCC, and significant correlation was observed between ADC, fp, Dt and histological grade.

Intraoperative ultrasound for prediction of hepatocellular carcinoma biological behaviour: Prospective comparison with pathology

BACKGROUND & AIMS

Preoperative prediction of both microinvasive hepatocellular carcinoma and histological grade of hepatocellular carcinoma is pivotal to treatment planning and prognostication. The aim of this study was to evaluate whether some intraoperative ultrasound features correlate with both the presence of same histological patterns and differentiation grade of hepatocellular carcinoma on the histological features of the primary resected tumour.

METHODS

All patients with single, small hepatocellular carcinoma that underwent hepatic resection were included in this prospective double-blind study: the intraoperative ultrasound patterns of nodule were registered and compared with similar histological features.

RESULTS

A total of 179 patients were enclosed in this study: 97 (54%) patients (34% in HCC ≤2 cm) had a microinvasive hepatocellular carcinoma at ultrasound examination, while 82 (46%) patients (41% in HCC ≤2 cm) at histological evaluation. Statistical analysis showed that diameters ≤2 cm, presence of satellites and microinvasive hepatocellular carcinoma at ultrasound examination were the variables with the strongest association with the histological findings. In the multivariate analysis, the vascular microinfiltration and infiltrative hepatocellular carcinoma aspect were independent predictors for grading.

CONCLUSIONS

In patients with cirrhosis and hepatocellular carcinoma, the prevalence of microinvasive hepatocellular carcinoma is high, even in cases of HCC ≤2 cm. Intraoperative ultrasound findings strongly correlated with histopathological criteria in detecting microinvasive patterns and are useful to predict neoplastic differentiation. The knowledge of these features prior to treatment are highly desired (this can be obtained by an intraoperative ultrasound examination), as they could help in providing optimal management of patients with hepatocellular carcinoma.

Histological Grading of Hepatocellular Carcinomas with Intravoxel Incoherent Motion Diffusion-weighted Imaging: Inconsistent Results Depending on the Fitting Method

Purpose:

To compare the abilities of three intravoxel incoherent motion (IVIM) imaging approximation methods to discriminate the histological grade of hepatocellular carcinomas (HCCs).

Methods:

Fifty-eight patients (60 HCCs) underwent IVIM imaging with 11 b-values (0–1000 s/mm²). Slow (D) and fast diffusion coefficients (D^*) and the perfusion fraction (f) were calculated for the HCCs using the mean signal intensities in regions of interest drawn by two radiologists. Three approximation methods were used. First, all three parameters were obtained simultaneously using non-linear fitting (method A). Second, D was obtained using linear fitting (b = 500 and 1000), followed by non-linear fitting for D^* and f (method B). Third, D was obtained by linear fitting, f was obtained using the regression line intersection and signals at b = 0, and non-linear fitting was used for D^* (method C). A receiver operating characteristic analysis was performed to reveal the abilities of these methods to distinguish poorly-differentiated from well-to-moderately-differentiated HCCs. Inter-reader agreements were assessed using intraclass correlation coefficients (ICCs).

Results:

The measurements of D, D^*, and f in methods B and C (Az-value, 0.658–0.881) had better discrimination abilities than did those in method A (Az-value, 0.527–0.607). The ICCs of D and f were good to excellent (0.639–0.835) with all methods. The ICCs of D^* were moderate with methods B (0.580) and C (0.463) and good with method A (0.705).

Conclusion:

The IVIM parameters may vary depending on the fitting methods, and therefore, further technical refinement may be needed.

MR elastography of hepatocellular carcinoma: Correlation of tumor stiffness with histopathology features-Preliminary findings

PURPOSE

To determine if tumor stiffness by MR Elastography (MRE) is associated with hepatocellular carcinoma (HCC) pathologic features.

MATERIAL AND METHODS

A retrospective review was undertaken of all patients with pathologically confirmed HCC who underwent MRE prior to loco-regional therapy, surgical resection or transplant between 1/1/2007 to 12/31/2015. An independent observer measured tumor stiffness (kilopascals, kPa) by drawing regions of interest (ROI) covering the HCC and in the case of HCCs with non-enhancing/necrotic components, only the solid portion was included in the ROI. HCC tumor grade (WHO criteria), vascular invasion and tumor encapsulation were assessed from retrievable pathology specimens by an expert hepatobiliary pathologist. Tumor stiffness was compared by tumor grade, size, presence of capsule and vascular invasion using Student's t-test (or Exact Mann-Whitney test).

RESULTS

21 patients were identified who had pathologically confirmed HCCs and tumor MRE data. 17 patients (81.0%) had underlying chronic liver disease. The mean±SD tumor size (cm) was 5.3±3.9cm. The mean±SD tumor stiffness was 5.9±1.4kPa. Tumors were graded as well differentiated (N=2), moderately differentiated (N=11) and poorly differentiated (N=8). There was a trend toward increased tumor stiffness in well/moderately differentiated HCCs (6.5±1.2kPa; N=13) compared to poorly differentiated HCCs (4.9±1.2kPa; N=8) (p<0.01). There was no significant correlation between tumor stiffness and liver stiffness or tumor size. There was no significant difference in tumor stiffness by presence or etiology of chronic liver disease, vascular invasion or tumor encapsulation.

CONCLUSION

Preliminary data suggest that tumor stiffness by MRE may be able to differentiate HCC tumor grade.

Diffusion-weighted imaging of hepatocellular carcinomas: a retrospective analysis of correlation between apparent diffusion coefficients and histological grade

PURPOSE

To define correlations between the pathological grades of hepatocellular carcinomas (HCCs) and apparent diffusion coefficients (ADCs) derived using breath-holding diffusion-weighted imaging (BH-DWI).

METHODS

We retrospectively evaluated 94 patients (105 lesions) with pathologically proved HCC who underwent hepatic DWI on a 3.0-T MR platform. HCCs were divided into five groups: well-differentiated (n = 10), well-to-moderately differentiated (n = 11), moderately differentiated (n = 51), moderately to poorly differentiated (n = 20), and poorly differentiated (n = 13) groups. The ADCs of carcinomas across different histological grades were compared by one-way analysis of variance. Spearman's rank correlation test was used to analyze correlations between the degree of histopathological differentiation and ADC. Results were corrected for multiple comparisons using the Bonferroni correction.

RESULTS

The BH technique yielded ADC values that differed significantly by the extent of differentiation (F = 8.392, p < 0.001). A significant negative correlation was found between the extent of differentiation and ADCs (r = -0.462, p < 0.001). The mean ADC values of poorly differentiated HCCs were significantly lower than the well-, well-to-moderately, moderately, and moderately to poorly differentiated HCCs (p values were <0.001, <0.001, 0.003, and 0.031, respectively).

CONCLUSION

ADC values obtained with BH-DWI may be of importance to non-invasively predict HCC tumor differentiation, and the extent of histological HCC differentiation was inversely correlated with ADC values.

Diffusion-Weighted Imaging with Two Different b-Values in Detection of Solid Focal Liver Lesions

One hundred and eighty-two consecutive patients with suspected liver disease were recruited to receive diffusion-weighted imaging (DWI) with two different b-values, in comparison with T2-weighted imaging (T2WI). The detection rate of three MR sequences in solid focal liver lesions (FLLs) and subgroup analyses were performed. Our prospective study found that DWI600 was equivalent to DWI100 and T2WI for the detection of solid FLLs overall but was significantly more accurate in the detection of malignant solid FLLs and lesions larger than 10 mm.

Multiparametric MR Imaging in Abdominal Malignancies

Modern MR imaging protocols can yield both anatomic and functional information for the assessment of hepatobiliary and pancreatic malignancies. Diffusion-weighted imaging is fully integrated into state-of-the-art protocols for tumor detection, characterization, and therapy monitoring. Hepatobiliary contrast agents have gained ground in the evaluation of focal liver lesions during the last years. Perfusion MR imaging is expected to have a central role for monitoring therapy in body tumors treated with antivascular drugs. Approaches such as Magnetic resonance (MR) elastography and (1)H-MR spectroscopy are still confined to research centers, but with the potential to grow in a short time frame.

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.

Imaging of HCC-Current State of the Art

Early diagnosis of hepatocellular carcinoma (HCC) is crucial for optimizing treatment outcome. Ongoing advances are being made in imaging of HCC regarding detection, grading, staging, and also treatment monitoring. This review gives an overview of the current international guidelines for diagnosing HCC and their discrepancies as well as critically summarizes the role of magnetic resonance imaging (MRI) and computed tomography (CT) techniques for imaging in HCC. The diagnostic performance of MRI with nonspecific and hepatobililiary contrast agents and the role of functional imaging with diffusion-weighted imaging will be discussed. On the other hand, CT as a fast, cheap and easily accessible imaging modality plays a major role in the clinical routine work-up of HCC. Technical advances in CT, such as dual energy CT and volume perfusion CT, are currently being explored for improving detection, characterization and staging of HCC with promising results. Cone beam CT can provide a three-dimensional analysis of the liver with tumor and vessel characterization comparable to cross-sectional imaging so that this technique is gaining an increasing role in the peri-procedural imaging of HCC treated with interventional techniques.