Single-breath-hold T2WI liver MRI with deep learning-based reconstruction: A clinical feasibility study in comparison to conventional multi-breath-hold T2WI liver MRI.

OBJECTIVE: To investigate the clinical feasibility of single-breath-hold (SBH) T2-weighted (T2WI) liver MRI with deep learning-based reconstruction in the evaluation of image quality and lesion delineation, compared with conventional multi-breath-hold (MBH) T2WI. METHODS: One hundred and fifty-two adult patients with suspected liver disease were prospectively enrolled. Two independent readers reviewed images acquired with conventional MBH-T2WI and SBH-T2WI at 3.0 T MR scanner. For image quality analyses, motion artifacts scores and boundary sharpness scores were compared using nonparametric Wilcoxon matched pairs tests between MBH-T2WI and SBH-T2WI. With the reference standard, 89 patients with 376 index lesions were included for lesion analyses. The lesion detection rates were compared by chi-square test, the lesion conspicuity scores and lesion-liver contrast ratio (CR) were compared using nonparametric Wilcoxon matched pairs tests between the two sequences. RESULTS: For both readers, motion artifacts scores of SBH-T2WI were significantly lower than MBH-T2WI (P < 0.001). Boundary sharpness scores of SBH-T2WI were significantly higher than MBH-T2WI (P < 0.001). The lesion detection rates for SBH-T2WI were significantly higher than MBH-T2WI (P < 0.001); the differences of lesion detection rates between the two sequences were statistically significant for small (≤ 10 mm) liver lesions (P < 0.001), while not significant for larger (> 10 mm) lesions (P > 0.05). Lesion conspicuity scores were significantly higher on SBH-T2WI than MBH-T2WI in the entire cohort as well as in both stratified subgroups of lesions ≤10 mm and > 10 mm (P < 0.001 for all). CRs for focal liver lesions were also significantly higher with SBH-T2WI (P < 0.001). CONCLUSION: The SBH-T2WI sequence with deep-learning based reconstruction showed promising performance as it provided significantly better image quality, lesion detectability, lesion conspicuity and contrast within a single breath-hold, compared with the conventional MBH-T2WI.

Multi-scale and multi-parametric radiomics of gadoxetate disodium-enhanced MRI predicts microvascular invasion and outcome in patients with solitary hepatocellular carcinoma ≤ 5 cm.

OBJECTIVES: To develop radiomics-based nomograms for preoperative microvascular invasion (MVI) and recurrence-free survival (RFS) prediction in patients with solitary hepatocellular carcinoma (HCC) ≤ 5 cm. METHODS: Between March 2012 and September 2019, 356 patients with pathologically confirmed solitary HCC ≤ 5 cm who underwent preoperative gadoxetate disodium-enhanced MRI were retrospectively enrolled. MVI was graded as M0, M1, or M2 according to the number and distribution of invaded vessels. Radiomics features were extracted from DWI, arterial, portal venous, and hepatobiliary phase images in regions of the entire tumor, peritumoral area ≤ 10 mm, and randomly selected liver tissue. Multivariate analysis identified the independent predictors for MVI and RFS, with nomogram visualized the ultimately predictive models. RESULTS: Elevated alpha-fetoprotein, total bilirubin and radiomics values, peritumoral enhancement, and incomplete or absent capsule enhancement were independent risk factors for MVI. The AUCs of MVI nomogram reached 0.920 (95% CI: 0.861-0.979) using random forest and 0.879 (95% CI: 0.820-0.938) using logistic regression analysis in validation cohort (n = 106). With the 5-year RFS rate of 68.4%, the median RFS of MVI-positive (M2 and M1) and MVI-negative (M0) patients were 30.5 (11.9 and 40.9) and > 96.9 months (p < 0.001), respectively. Age, histologic MVI, alkaline phosphatase, and alanine aminotransferase independently predicted recurrence, yielding AUC of 0.654 (95% CI: 0.538-0.769, n = 99) in RFS validation cohort. Instead of histologic MVI, the preoperatively predicted MVI by MVI nomogram using random forest achieved comparable accuracy in MVI stratification and RFS prediction. CONCLUSIONS: Preoperative radiomics-based nomogram using random forest is a potential biomarker of MVI and RFS prediction for solitary HCC ≤ 5 cm. KEY POINTS: • The radiomics score was the predominant independent predictor of MVI which was the primary independent risk factor for postoperative recurrence. • The radiomics-based nomogram using either random forest or logistic regression analysis has obtained the best preoperative prediction of MVI in HCC patients so far. • As an excellent substitute for the invasive histologic MVI, the preoperatively predicted MVI by MVI nomogram using random forest (MVI-RF) achieved comparable accuracy in MVI stratification and outcome, reinforcing the radiologic understanding of HCC angioinvasion and progression.

Magnetic resonance texture analysis for the identification of cytokeratin 19-positive hepatocellular carcinoma.

PURPOSE: To investigate potential findings associated with cytokeratin 19 (CK19)-positive HCC, with special emphasis on MR texture analysis. MATERIALS AND METHODS: Forty-eight patients with CK19-negative HCC and 38 patients with CK19-positive were retrospectively evaluated by texture analysis based on conventional MRI. Clinicalpathological characteristics, conventional MR imaging findings, and the MR texture analysis contained of 2415 texture features in the seven conventional sequences were compared. Significant features for differentiating were identified by univariate and multivariate analyses. Receiver operating characteristic analyses of the significant findings were performed and compared to evaluate their diagnostic performance. RESULTS: There was no significant difference between the top1 texture feature (three-dimensional standard deviation separation of intensity on T2-weighted original images, abbreviated as: StdSeparation 3D) and the combined top1-6 feature in identifying CK19-positive HCC(P = 0.660). Univariate and multivariate analyses indicated that serum alpha-fetoprotein (AFP) level ≥400 ng/mL(P = 0.013), arterial rim enhancement(P = 0.005), and StdSeparation 3D texture character(P = 0.002) were independent variables associated with CK19-positive HCCs. The combination of the three indices showed a better performance than AFP level(P = 0.0028), arterial rim enhancement(P < 0.0001), and their combination(P = 0.0098); while no significantly better than the StdSeparation 3D texture character alone(P = 0.0788). An acceptable discrimination(AUC = 0.765) with both sensitivity and specificity greater than 75% was achieved for StdSeparation 3D texture character. CONCLUSION: Serum AFP level ≥400 ng/mL, arterial rim enhancement, and the StdSeparation 3D texture character were independently associated with CK19-positive HCC. The StdSeparation 3D texture character may be a reliable imaging biomarker which can improve the diagnostic performance.

Assessing liver fibrosis in chronic hepatitis B using MR extracellular volume measurements: Comparison with serum fibrosis indices.

OBJECTIVES: To evaluate the diagnostic value of liver extracellular volume (ECVliver) measurement by equilibrium MR in staging liver fibrosis in chronic hepatitis B (CHB) patients, and to compare its performance with serum fibrosis indices. MATERIALS AND METHODS: 91 CHB patients were included and underwent gadopentetate dimeglumine-enhanced MRI with T1 mapping sequence before and 15-min after contrast. ECVliver, aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis index based on the four factors (FIB-4) were calculated and compared between fibrosis subgroups, and the correlations between the three indices and fibrosis stage or inflammatory activity were measured by Spearman correlation analysis and stepwise multiple regression analysis. Diagnostic performance in evaluating liver fibrosis stage was assessed and compared using receiver operating characteristic analysis. RESULTS: Interobserver agreement showed an excellent interclass correlation coefficient of 0.895 for ECVliver. ECVliver, APRI and FIB-4 were different between fibrosis stages as a whole (F/H = 18.44-24.36, P ≤ 0.001). ECVliver had the strongest correlation with fibrosis stage (r = 0.727, P < 0.001), while APRI and FIB-4 had weak correlations (r = 0.466 and 0.440, P < 0.001). Multivariate analysis showed that only ECVliver was independently correlated with fibrosis stage (P < 0.001). The fibrosis stage was the only independent factor correlated with ECVliver comparing to inflammatory activity (P < 0.001). AUCs of ECVliver were larger than both APRI and FIB-4 in fibrosis staging, with significant differences in the diagnosis of advanced fibrosis (≥F3) and cirrhosis (F4) (P = 0.0024 to 0.0049). CONCLUSION: MR ECVliver provides a promising noninvasive tool in staging liver fibrosis for CHB patients, superior to the fibrosis indices of APRI and FIB-4.

Skewness of apparent diffusion coefficient (ADC) histogram helps predict the invasive potential of intraductal papillary neoplasms of the bile ducts (IPNBs).

OBJECTIVE: This retrospective study was to explore the value of whole lesion apparent diffusion coefficient (ADC) histogram in distinguishing invasive and noninvasive intraductal papillary neoplasms of the bile ducts (IPNBs). METHOD AND MATERIALS: Fifty-two patients of IPNB underwent MRI at 1.5T with diffusion-weighted imaging (DWI, b = 500 s/mm2) before surgical resections. ADC histogram metrics were generated by using the software MR OncoTreat. The mean, standard deviation, median, skewness, kurtosis as well as the 10th, 25th, 75th, and 90th percentiles were compared between pathologically defined invasive (n = 35) and noninvasive (n = 17) IPNBs. Such conventional imaging characters as lesion location, bile duct wall dilation, and mural nodularity were also assessed. Multivariate regression analysis as well as receiver operating characteristics (ROC) analysis were then conducted to determine the predictive factors and to evaluate potential diagnostic performances. RESULTS: The inter-operator reliability was good to excellent (ICC: 0.693-979). Mean median, kurtosis, and the 10th, 25th, 75th, 90th percentiles were all greater in noninvasive group than invasive ones (P: 0.00-002). Skewness was lower in noninvasive group than invasive ones (- 1.0 ± 0.6 vs. - 0.3 ± 0.6, P = 0.00). After multivariate regression, skewness (AUC = 0.822, 95%CI 0.70-0.91) and mural nodularity (accuracy = 0.808) were the only two independent factors in predicting invasive IPNBs. The diagnostic performance improved (AUC = 0.867, 95%CI 0.742-0.946) when combining skewness and mural nodularity, however, the difference did not reach statistical significance (P = 0.16). CONCLUSION: The ADC histogram has capability of distinguishing invasive and noninvasive IPNBs, in which skewness was an independent predictive factor.

Histogram Analysis of Diffusion Kurtosis Magnetic Resonance Imaging for Diagnosis of Hepatic Fibrosis.

Objective: To investigate the diagnostic value of diffusion kurtosis imaging (DKI) histogram analysis in hepatic fibrosis staging. Materials and Methods: Thirty-six rats were divided into carbon tetrachloride-induced fibrosis groups (6 rats per group for 2, 4, 6, and 8 weeks) and a control group (n = 12). MRI was performed using a 3T scanner. Histograms of DKI were obtained for corrected apparent diffusion (D), kurtosis (K) and apparent diffusion coefficient (ADC). Mean, median, skewness, kurtosis and 25th and 75th percentiles were generated and compared according to the fibrosis stage and inflammatory activity. Results: A total of 35 rats were included, and 12, 5, 5, 6, and 7 rats were diagnosed as F0-F4. The mean, median, 25th and 75th percentiles, kurtosis of D map, median, 25th percentile, skewness of K map, and 75th percentile of ADC map demonstrated significant correlation with fibrosis stage (r = -0.767 to 0.339, p < 0.001 to p = 0.039). The fibrosis score was the independent variable associated with histogram parameters compared with inflammatory activity grade (p < 0.001 to p = 0.041), except the median of K map (p = 0.185). Areas under the receiver operating characteristic curve of D were larger than K and ADC maps in fibrosis staging, although no significant differences existed in pairwise comparisons (p = 0.0512 to p = 0.847). Conclusion: Corrected apparent diffusion of DKI histogram analysis provides added value and better diagnostic performance to detect various liver fibrosis stages compared with ADC.

The diagnosis of coronary plaque stability by multi-slice computed tomography coronary angiography.

BACKGROUND: Coronary computed tomographic angiography is a robust non-invasive method to assess coronary artery disease (CAD) and analyze coronary plaque stability, especially for the non-calcified plaques. The aim of this study was to investigate the differential characteristics between the unstable coronary plaques and the stable coronary plaques using multi-slice computed tomography (MSCT). METHODS: Sixty patients with coronary heart disease (37 unstable plaques and 31 stable plaques) were included. The napkin ring thickness, napkin-ring sign, plaque CT attenuation and degree of lumen stenosis were retrospectively analyzed. The diagnostic performances of MSCT were determined to predict the unstable plaques. The difference was statistically significant if P<0.05. RESULTS: The napkin ring thickness of the unstable plaques was thinner than that of the stable plaques (P<0.05). The napkin-ring sign was more frequently observed in the unstable group (89.2%) than the stable group (22.6%, P<0.05). The average CT value of the unstable plaques (26.8±17.8 HU) was lower than that of the stable plaques (68.5±25.5 HU, P<0.05). The unstable plaques had more severe lumen stenosis or occlusion (70.3%) than the stable plaques (41.9%, P<0.05). The measurable napkin ring thickness of the plaques with a cutoff value of 0.8 mm and an accuracy of 89.5% was one independent factor to predict unstable plaques. The optimal combined threshold of the napkin-ring sign and/or the plaque CT value of 53 HU with an accuracy of 80.9% was to predict unstable plaques. CONCLUSIONS: The optimal combined threshold of the napkin-ring sign and/or the plaque CT value ≤53 HU may be a good indicator to predict the unstable plaques in patients with CAD. The subgroup of measurable napkin ring thickness of the non-calcified plaques may also be an independent factor to predict the unstable plaques in patients with CAD.

Assessment of liver regeneration after associating liver partition and portal vein ligation for staged hepatectomy: a comparative study with portal vein ligation.

BACKGROUND: To investigate the diagnostic value of diffusion kurtosis imaging (DKI) and diffusion-weighted imaging (DWI) in assessing liver regeneration after associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) compared with portal vein ligation (PVL). METHODS: Thirty rats were divided into the ALPPS, PVL, and control groups. DKI and DWI were performed before and 7 days after surgery. Corrected apparent diffusion (D), kurtosis (K) and apparent diffusion coefficient (ADC) were calculated and compared, radiologic-pathologic correlations were evaluated. RESULTS: The volume of the right median lobe increased significantly after ALPPS. There were larger cellular diameters after ALPPS and PVL (P = 0.0003). The proliferative indexes of Ki-67 and hepatocyte growth factor were higher after ALPPS (P = 0.0024/0.0433). D, K and ADC values differed between the groups (P = 0.021/0.0015/0.0008). A significant correlation existed between D and the hepatocyte size (r = -0.523), no correlations existed in ADC and K (P = 0.159/0.111). The proliferative indexes showed moderate negative correlations with ADC (r = -0.484/-0.537) and no correlations with D and K (P = 0.100-0.877). DISCUSSION: Liver regeneration after ALPPS was effective and superior to PVL. DKI, especially the D map, may provide added value in evaluating the microstructure of liver regeneration after ALPPS, but this model alone may perform no better than the standard monoexponential model of DWI.

Histogram analyses of diffusion kurtosis indices and apparent diffusion coefficient in assessing liver regeneration after ALPPS and a comparative study with portal vein ligation.

PURPOSE: To investigate the value of diffusion kurtosis imaging (DKI) histogram analysis in assessing liver regeneration and the microstructure basis after associating liver partition and portal vein ligation for staged hepatectomy (ALPPS), in comparison with portal vein ligation (PVL). MATERIALS AND METHODS: Thirty rats were divided into the ALPPS, PVL, and control groups. Histograms of DKI using a 3T magnetic resonance imaging (MRI) scanner were performed for corrected apparent diffusion (D), kurtosis (K), and apparent diffusion coefficient (ADC). Mean, median, skewness, kurtosis, and the percentiles (5th , 25th , 50th , 75th , and 95th ) were generated and compared, and radiologic-pathologic correlations were evaluated. RESULTS: There were more significant volume increases of the right median lobe after ALPPS than PVL (P = 0.0304/0.0017). The ALPPS group had larger hepatocyte size (P = 0.009/0.000), higher Ki-67 and hepatocyte growth factor expression (P = 0.001-0.036) compared with both PVL and control groups. Mean, median, 5th , 25th , 50th , 75th percentiles of D map in ALPPS were lower than the control group (P = 0.001-0.022). Skewness and 75th , 95th percentiles of K map in ALPPS were higher than the PVL group (P = 0.011-0.042). No differences existed in the ADC map between groups (P = 0.073-0.291). Mean, median, 5th , 25th , 50th percentiles of D map, and 5th percentile of K map showed significant correlations with hepatocyte size (r = -0.582 to -0.426); no significant correlations were found in ADC parameters (P = 0.460-0.934). CONCLUSION: ALPPS induced true accelerated liver hypertrophy, superior to that seen with PVL. Histogram analysis of diffusion kurtosis indices may provide added values in evaluating liver regeneration and the intrinsic microstructure basis after ALPPS in comparison with the standard monoexponential ADC. LEVEL OF EVIDENCE: 3 Technical Efficacy Stage: Stage 2 J. Magn. Reson. Imaging 2018;47:729-736.

Assessment of liver fibrosis using T1 mapping on Gd-EOB-DTPA-enhanced magnetic resonance.

BACKGROUND: Few studies have investigated the value of Gd-EOB-DTPA-enhanced T1 mapping in exact fibrosis staging, especially its correlation with hepatic molecular transporters. AIMS: To investigate the diagnostic value of Gd-EOB-DTPA-enhanced T1 mapping in staging liver fibrosis and its relationship with hepatic molecular transporters. METHODS: Thirty rats were divided into the carbon tetrachloride-induced fibrosis groups and a control group. T1-mapping was performed before and 20min after administration of Gd-EOB-DTPA. The T1 relaxation time and reduction rate (Δ%) were calculated, and their correlations with the degree of fibrosis, necroinflammatory activity, iron load and hepatic molecular transporters were assessed and compared. RESULTS: Hepatobiliary phase T1 relaxation time (HBP) and Δ% were different between each adjacent fibrosis subgroups(P=0.000-0.042). Very strong correlations existed between fibrosis and both HBP and Δ% (r=0.960/-0.952), and multivariate analyses revealed that fibrosis was the only factor independently predicted by HBP (P=0.000) and Δ% (P=0.001), comparing to necroinflammatory activity and iron load. The expression of the organic anion transporting polypeptide1a1 (Oatp1a1) was significantly correlated with HBP and Δ% at both mRNA (r=-0.741/0.697) and protein (r=-0.577/0.602) levels. Weaker correlations were found for multidrug resistance associated protein2 (Mrp2). Generally, both transporters showed decreasing levels with increasing degrees of fibrosis. CONCLUSION: Gd-EOB-DTPA-enhanced T1 mapping may provide a reliable diagnostic tool in staging liver fibrosis, and can be regarded as a useful imaging biomarker of hepatocyte transporter function.

Role of MR in the differentiation of IgG4-related from non-IgG4-related hepatic inflammatory pseudotumor.

BACKGROUND: Hepatic inflammatory pseudotumor (IPT) is classified into 2 types based on IgG4 stain: IgG4-related and non-IgG4-related; the two types differ not only in their pathological characteristics, but also in the clinical features. This study aimed to investigate the MR character of hepatic IPT, and differentiate the IgG4-related IPT from the non-IgG4-related IPT. METHODS: Twenty-five patients with 27 histologically proven hepatic IPTs were retrospectively analyzed. Ten lesions were diagnosed as IgG4-related IPT, and the other 17 as non-IgG4-related IPT. The MR signal features on T1, T2-weighted, dynamic-enhanced, and diffusion-weighted imaging were evaluated and compared. RESULTS: The dominant lesions were subcapsularly distributed (n=17, 63.0%) with clear boundary (n=20, 74.1%), and showed progressive enhancement pattern (n=21, 77.8%) with diffuse homogeneous (n=12, 44.4%) or heterogeneous (n=8, 29.6%) hyperintensity, accompanied by delayed capsule-like enhancement (n=17, 63.0%) and central nonenhanced areas (n=18, 66.7%). Morphological features (P>0.05) were not sufficient to differentiate IgG4-related IPT from non-IgG4-related IPT; the wash-out pattern was only found in 2 IgG4-related IPT, while the progressive enhancement pattern was more common in the non-IgG4-related lesions (n=16) (P=0.022). During portal and delayed phases, iso-/hypoenhanced lesions were only seen in 3 IgG4-related IPT, and circular-enhanced lesions (n=5) existed exceptionally in the non-IgG4-related group with significant differences (P=0.029 and 0.027). Most IgG4-related IPTs had lower apparent diffusion coefficient compared with the liver parenchyma (n=6), while most non-IgG4-related IPTs had higher apparent diffusion coefficient value (n=13) (P=0.046). CONCLUSIONS: Although MR images of hepatic IPT have certain characteristics, they are not enough to differentiate IgG4-related IPT from non-IgG4-related IPT. The enhancement pattern, signal features on portal and delayed phases, and the apparent diffusion coefficient value of the lesion may be helpful for the diagnosis.

Diffusion kurtosis imaging and diffusion-weighted imaging in assessment of liver fibrosis stage and necroinflammatory activity.

PURPOSE: To investigate and compare the diagnostic value of diffusion kurtosis imaging (DKI) with diffusion-weighted imaging (DWI) in assessing and quantifying hepatic fibrosis. METHODS: Thirty rats were divided into the control group (n = 6) and the fibrosis experimental groups (n = 6 per group) with CCl4 administration for 2, 4, 6, and 8 weeks. Liver fibrosis stage (S) and necroinflammatory activity grade (G) were histopathologically determined. DKI and DWI were performed; mean apparent diffusion (MD), mean kurtosis (MK), and apparent diffusion coefficient (ADC) values were calculated. DKI parameters were compared with ADC values according to G/S scores. RESULTS: Strong inverse correlations were found between the degree of fibrosis and both MD and ADC (r = -0.840 and r = -0.760), while only weak correlation existed in MK (r = 0.405). ROC analyses demonstrated the AUC in MD, MK, and ADC of 0.862, 0.684, 0.817 for identifying mild and severe fibrosis, and 0.757, 0.675, 0.733 for non-cirrhosis and cirrhosis, respectively. The degree of fibrosis was significantly correlated with α-smooth muscle actin (α-SMA) (P < 0.0001); α-SMA had strong inverse correlation with MD (r = -0.723), moderate inverse correlation with ADC (r = -0.613), and very weak correlation with MK (r = 0.175). Additionally, MD was strongly correlated with the necroinflammatory activity (r = -0.758), ADC was moderately correlated (r = -0.492), and MK was weakly correlated (r = 0.254). CONCLUSION: DKI may provide added information and serve as a valuable tool for the characterization and surveillance of liver fibrosis in a non-invasive manner.

MR comparative study of combined hepatocellular-cholangiocarcinoma in normal, fibrotic, and cirrhotic livers.

PURPOSE: To compare MR imaging features of combined hepatocellular-cholangiocarcinoma (cHCC-CC) in normal, fibrotic, and cirrhotic livers. METHODS: A total of 64 patients with 67 pathologically proven cHCC-CCs were retrospectively analyzed. Patients were classified into three groups according to the patients' liver condition: patients with normal liver (F0, group 1), fibrosis without cirrhosis (F1-3, group 2), and cirrhosis (F4, group 3). The morphological and MR signal features on T1- and T2-weighted, dynamic contrast-enhanced, diffusion-weighted imaging, as well as the accompanying imaging findings, were evaluated and compared. RESULTS: There were 12, 19, and 33 patients in groups 1, 2, and 3, respectively. Tumors in the fibrotic and cirrhotic livers were smaller than those in the normal liver, and tumors with cirrhosis had the smallest size (P = 0.0326). No statistical difference was found when comparing the signal intensity on T2-weighted imaging (P = 0.496), but iso- or hypointense lesions were only found in the fibrosis (n = 2) or cirrhosis group (n = 2). Enhancement pattern was different between groups, the washout pattern was more often seen in the cirrhosis group (P = 0.049), and the accompanying mosaic architecture was also more commonly seen in the cirrhosis group (P = 0.048). The ADC values of the lesions were not different among the three groups (P = 0.899). CONCLUSION: MRI may provide valuable information for the diagnosis and differential diagnosis of cHCC-CC in normal, fibrotic, and cirrhotic livers. The nodule size, enhancement pattern, and the presence of mosaic architecture in cHCC-CC differ between different degrees of background liver disease.

Intrahepatic distant recurrence following complete radiofrequency ablation of small hepatocellular carcinoma: risk factors and early MRI evaluation.

BACKGROUND: Radiofrequency ablation (RFA) is related to a high intrahepatic distant recurrence (IDR) rate, and the associations between IDR and relevant imaging features have not yet been fully investigated. This study aimed to determine both clinical and imaging risk factors of IDR after complete RFA for HBV-related small hepatocellular carcinoma (HCC) (≤ 3 cm). METHODS: Thirty-five patients (29 men and 6 women; mean age 60.7 years) with 40 HBV-related small HCCs who underwent complete RFA were included in our study. The incidence and potential clinical and MR imaging risk factors for IDR after RFA were assessed using the Kaplan-Meier method, the log-rank test and a stepwise Cox hazard model. RESULTS: The median follow-up period was 25 (4-45) months, and IDR was observed in 20 (57.1%) patients. The 12- and 24-month cumulative IDR-free survival rates were 76.7% and 61.3%, respectively. Univariate analysis revealed that pretreatment albumin < 3.5 g/dL (P = 0.026), multinodular tumor (P = 0.032), ablative margin < 3 mm (P = 0.007), no or disrupted periablational enhancement within 24 hours (P = 0.001) and at 1 month (P = 0.043) after RFA, and hyperintensity of the central ablative zone on T1-weighted images (T1WI) at 1 month after RFA (P = 0.004) were related to IDR. Multivariate analysis showed that pretreatment albumin < 3.5 g/dL (P = 0.032), multinodular tumor (P = 0.012), no or disrupted periablational enhancement within 24 hours after RFA (P = 0.001), and hyperintensity of the central ablative zone on T1WI at 1 month after RFA (P = 0.003) were independent risk factors for IDR. During the 1-month follow-up, the apparent diffusion coefficient exhibited an up-and-down evolution without significant value in the prediction of IDR following RFA. CONCLUSIONS: Patients with HBV-related small HCC had a high IDR rate after RFA. The risk factors included low serum albumin, multiple nodules, lesions with no or disrupted periablational enhancement and persistent hyperintensity in the central ablative zone on T1WI within 1 month after RFA.

MR features of small hepatocellular carcinoma in normal, fibrotic, and cirrhotic livers: a comparative study.

PURPOSE: The objective of this study is to compare MR imaging features of small hepatocellular carcinoma (HCC) (≤ 2 cm) in normal, fibrotic, and cirrhotic liver. METHODS: A total of 215 patients with 235 pathologically proven sHCC were retrospectively analyzed. Patients were classified into three groups according to the patients' liver condition: patients with normal liver (F0, group 1), fibrosis without cirrhosis (F1-3, group 2), and cirrhosis (F4, group 3). The morphological and MR signal features on T1, T2-weighted, dynamic enhanced, and diffusion-weighted imaging were evaluated and compared. RESULTS: There were 10, 38, and 167 patients in group 1, 2, and 3, respectively. Patients with normal liver were older than those with fibrosis or cirrhosis (P = 0.0086), and tumors in the normal liver were larger than those in the fibrotic or cirrhotic liver (P = 0.0407). No statistical differences were found among groups in signals on T2-weighted images (P = 0.163), signals on each phase after contrast (P = 0.269, 0.893, and 0.259, respectively), enhancement patterns (P = 0.753), ADC values (P = 0.760), as well as the presence of capsule-like enhancement (P = 0.953), mosaic pattern (P = 0.572), fat content (P = 0.222), iron sparing (P = 1.000), hemorrhage (P = 0.181), and venous invasion (P = 0.175). Both signal-to-noise ratios (SNR) (χ (2) = 2.045, P = 0.132) and lesion-to-liver contrast-to-noise ratios (CNR) (χ (2) = 0.438, P = 0.646) were not different as well. But confusing features of iso/hypointensity on T2-weighted imaging (n = 11, 6.0%) and progressive enhancement pattern (n = 2, 1.1%) were exclusively found in the cirrhosis background, and hypovascular tumors with iso/hypointensity on arterial phase were only seen in the fibrosis (n = 5, 11.9%) and cirrhosis groups (n = 10, 5.5%). CONCLUSION: MR features of sHCC were similar among patients with normal, fibrotic, and cirrhotic livers.

MRI of small intrahepatic mass-forming cholangiocarcinoma and atypical small hepatocellular carcinoma (≤3 cm) with cirrhosis and chronic viral hepatitis: a comparative study.

OBJECTIVE: The objective was to identify the decision-making magnetic resonance (MR) features in differentiating small intrahepatic mass-forming cholangiocarcinoma (sIMCC) from atypical small hepatocellular carcinoma (sHCC) (≤3 cm) in patients with cirrhosis and chronic viral hepatitis. METHODS: Signal features and relative contrast of sHCCs and sIMCCs in T2-weighted and dynamic enhanced imaging were analyzed. A subgroup comparison between the cirrhosis and noncirrhosis chronic viral hepatitis group was also made. RESULTS: Univariate analysis revealed that tumor contours (P<.001), signals in T2-weighted (P<.001) and each phase of contrast-enhanced scanning (P<.001), enhancement patterns (P<.001), as well as accompanying findings of tumor capsule (P<.001), hepatic capsule retraction (P<.001), bile duct dilation (P=.031), and transient hepatic intensity difference (P=.002) were different between sIMCC and atypical sHCC. Multivariate analysis indicated that dynamic enhancement patterns (P<.001) and signals in T2-weighted images (P=.024) were independent predictors for differentiation. Confusing MR features were more often observed in the cirrhosis group compared with those in the noncirrhosis chronic viral hepatitis group. CONCLUSION: Dynamic enhancement patterns and signals in T2-weighted images were the most important MR features to differentiate sIMCC from atypical sHCC with cirrhosis and chronic viral hepatitis.