Cholangiocarcinoma, the second most common hepatobiliary malignancy after hepatocellular carcinoma, is a heterogeneous disease entity with widely varying radiologic features, clinical behavior, and ...treatment approaches. In the detection, characterization, staging, and resectability assessment of cholangiocarcinoma, imaging studies are indispensable. Herein, an overview of the state-of-the-art imaging techniques is presented for the evaluation of intrahepatic and perihilar cholangiocarcinoma, as well as complementary multimodality and multiparametric imaging approaches for a more comprehensive evaluation. In addition, classification systems, new pathologic concepts in cholangiocarcinogenesis and premalignant lesions, and current trends in treatment approaches, which are vital to the imaging interpretation of cholangiocarcinoma, will be discussed.
RSNA, 2018.
Objectives
This study was conducted in order to assess the performance of the Liver Imaging Reporting and Data System (LI-RADS) treatment response (TR) (LR-TR) categorization on gadoxetic ...acid-enhanced MRI (Gd-EOB-MRI) for detecting viable tumors in hepatocellular carcinoma (HCC) treated with locoregional treatment (LRT) and to investigate the added value of ancillary features (AFs) to conventional enhancement-based criteria.
Methods
This retrospective study included 183 patients with Gd-EOB-MRI after LRT for HCC and appropriate reference standards for tumor viability (84 viable and 99 nonviable). Two independent radiologists assigned per-lesion mRECIST and TR categories (TR-nonviable, TR-equivocal, or TR-viable) according to the LR-TR algorithm and modified LR-TR algorithms including mLR-TR(TP) allowing transitional phase (TP) washout and mLR-TR(AF) allowing category adjustment by applying AFs. Diagnostic performances of imaging criteria were compared using the Cochran’s
Q
test with post hoc analysis.
Results
For detecting viable tumors, LR-TR-viable resulted in sensitivities of 64.5%/39.3% and specificities of 98.0%/98.0% in reviewers 1/2. In comparison to LR-TR-viable, mRECIST-viable, mLR-TR(TP)-viable, and mLR-TR(AF)-viable showed significantly higher sensitivities (92.9%/94.0%, 77.4%/56.6%, and 86.9%/83.3% in reviewers 1/2) (
p
s < 0.001). The specificity of mRECIST-viable (73.7%/62.6%) was significantly lower than that of LR-TR-viable (
p
s < 0.001), while those of mLR-TR(TP)-viable and mLR-TR(AF)-viable were greater than 95% (98.0%/96.0% and 97.0%/96.0%), statistically equivalent to LR-TR-viable (
p
s > 0.05). TR-equivocal was least assigned on mLR-TR(AF) (1.1%/7.7%) than LR-TR (15.8%/32.2%) or mLR-TR(TP) (6.6%/23.5%) in both reviewers.
Conclusion
The LR-TR algorithm on Gd-EOB-MRI provides a specific diagnosis of viable tumor but with limited sensitivity. By applying AFs in the category adjustment, more sensitive and confident diagnosis can be achieved without significant loss of specificity.
Key Points
• The LI-RADS treatment response (LR-TR) algorithm on Gd-EOB-MRI provides a highly specific diagnosis of viable HCC but with limited sensitivity.
• The inferior sensitivity of LR-TR-viable category to that of mRECIST can be improved by applying ancillary features in the category adjustment.
Intraoperative ultrasonography (IOUS) has been widely utilized in hepatic surgery both as a diagnostic technique and in the course of treatment. Since IOUS involves direct-contact imaging of the ...target organ, it can provide high spatial resolution without interference from the surrounding structures. Therefore, IOUS may improve the detection, characterization, localization, and local staging of hepatic tumors. IOUS is also a real-time imaging modality capable of providing interactive information and valuable guidance in a range of procedures. Recently, contrast-enhanced IOUS, IOUS elastography, and IOUS-guided hepatic surgery have attracted increasing interest and are expected to lead to the broader implementation of IOUS. Herein, we review the various applications of IOUS in the diagnosis and management of focal hepatic lesions.
Objectives
The aim of this study was to develop a deep convolutional neural network (DCNN) for the prediction of the METAVIR score using B-mode ultrasonography images.
Methods
Datasets from two ...tertiary academic referral centers were used. A total of 13,608 ultrasonography images from 3446 patients who underwent surgical resection, biopsy, or transient elastography were used for training a DCNN for the prediction of the METAVIR score. Pathological specimens or estimated METAVIR scores derived from transient elastography were used as a reference standard. A four-class model (F0 vs. F1 vs. F23 vs. F4) was developed. Diagnostic performance of the algorithm was validated on a separate internal test set of 266 patients with 300 images and external test set of 572 patients with 1232 images. Performance in classification of cirrhosis was compared between the DCNN and five radiologists.
Results
The accuracy of the four-class model was 83.5% and 76.4% on the internal and external test set, respectively. The area under the receiver operating characteristic curve (AUC) for classification of cirrhosis (F4) was 0.901 (95% confidence interval CI, 0.865–0.937) on the internal test set and 0.857 (95% CI, 0.825–0.889) on the external test set, respectively. The AUC of the DCNN for classification of cirrhosis (0.857) was significantly higher than that of all five radiologists (AUC range, 0.656–0.816;
p
value < 0.05) using the external test set.
Conclusions
The DCNN showed high accuracy for determining METAVIR score using ultrasonography images and achieved better performance than that of radiologists in the diagnosis of cirrhosis.
Key Points
•
DCNN accurately classified the ultrasonography images according to the METAVIR score.
•
The AUROC of this algorithm for cirrhosis assessment was significantly higher than that of radiologists.
•
DCNN using US images may offer an alternative tool for monitoring liver fibrosis.
Abstract
To evaluate the role of dysmorphic intratumoral vessels as imaging marker for the prediction of high lung shunt fraction (LSF) in patients with hepatocellular carcinoma (HCC). This ...retrospective study included 403 patients with HCC who underwent a planning arteriography for transarterial radioembolization with administration of
99m
Tc-macroaggregated albumin to calculate LSF. The LSF was measured by using planar body scans. Two radiologists evaluated the pre-treatment contrast-enhanced CT findings, including tumor number, size, margin, distribution, tumor burden, portal and hepatic vein invasion, early hepatic vein enhancement, and dysmorphic intratumoral vessels. The logistic regression analysis was performed to determine significant predictors for high LSF > 20%. Using the identified predictors, diagnostic criteria for high LSF were proposed. Among 403 patients, 52 (13%) patients had high LSF > 20%, and dysmorphic tumor vessels were present in 115 (28.5%) patients. Predictors for LSF > 20% were tumor size > 11 cm, hepatic vein invasion, early hepatic vein enhancement, and dysmorphic intratumoral vessel. If the patient had three or more of the four predictors for LSF > 20% on imaging, the accuracy and specificity for diagnosing LSF > 20% were 88.8% and 96.3% respectively. Dysmorphic intratumoral vessel in HCC is an imaging marker suggesting a high LSF, which may be applicable to treatment modification or patient exclusion for radioembolization with combined interpretation of tumor size and hepatic vein abnormality.
Objectives
To compare diagnostic performances of current guidelines for the diagnosis of HCC in LT candidates using gadoxetic acid–enhanced liver MRI (Gd-EOB-MRI).
Methods
Eighty-one patients (119 ...HCCs and 35 non-HCCs) who underwent preoperative Gd-EOB-MRI and subsequent LT were included. Per-lesion imaging diagnoses of HCCs were made using four different guidelines (American Association for the Study of Liver Disease (AASLD), European Association for the Study of the Liver (EASL), Asian Pacific Association for the Study of the Liver (APASL), and Korean Liver Cancer Association-National Cancer Center (KLCA-NCC) guidelines, and patient allocation was determined according to Milan criteria (MC). Comparisons of per-lesion sensitivity, specificity, and accuracy of patient allocation between guidelines were performed using logistic regression with generalized estimating equations.
Results
For diagnosis of HCC, AASLD guideline showed highest specificity (97.4%), followed by EASL and KLCA-NCC guidelines (92.1% and 92.1%,
p
> 0.99 and = 0.15, respectively, in comparison to AASLD), while the specificity of APASL guideline was significantly lower than that of AASLD guideline (78.9% vs. 97.4%,
p
= 0.006). APASL and KLCA-NCC guidelines (75.9% and 65.6%) showed significantly higher sensitivities than AASLD/EASL guidelines (34.5% and 38.8%, respectively; all
p
s < 0.001). For organ allocation, KLCA-NCC guideline showed higher accuracy in selecting unsuitable candidates (with non-HCC malignancies or beyond MC HCCs) than EASL guideline (68.4% vs. 31.8%;
p
= 0.001).
Conclusion
For the diagnosis of HCCs using Gd-EOB-MRI, AASLD guideline provided the highest specificity, followed by EASL, KLCA-NCC, and APASL guidelines with statistically significant difference with only APASL guideline. KLCA-NCC guideline provided the most accurate selection of unsuitable LT candidates.
Key Points
•
AASLD/LI-RADS showed the highest specificity, followed by EASL and KLCA-NCC guidelines.
•
APASL and KLCA-NCC guidelines allowed more sensitive diagnoses of HCCs.
•
KLCA-NCC more accurately classified patients not appropriate transplantation candidates than EASL.
To compare magnetic resonance (MR) elastography and ultrasonographic shear-wave elastography ( SWE shear-wave elastography ) for the staging of hepatic fibrosis ( HF hepatic fibrosis ) in the same ...individuals.
This prospective study was approved by the institutional review board, and informed consent was obtained from all patients. The technical success of and reliable liver stiffness ( LS liver stiffness ) measurement rates at MR elastography and SWE shear-wave elastography were compared in 129 patients who underwent both examinations. For mutual validation, LS liver stiffness values measured at both examinations were correlated by using Pearson correlation. The diagnostic performance of the two techniques for the assessment of substantial HF hepatic fibrosis (stage ≥ F2) was compared by using nonparametric receiver operating characteristic analysis.
The technical success rates of MR elastography and SWE shear-wave elastography were 95.35% (123 of 129) and 97.67% (126 of 129), respectively (P = .51). MR elastography provided significantly more reliable LS liver stiffness measurements than did SWE shear-wave elastography (95.35% 123 of 129 vs 75.2% 97 of 129, P < .001). The two examinations showed moderate correlation (r = 0.724). In patients with HF hepatic fibrosis stages of F3 or lower, the two examinations showed moderate-to-strong correlation (r = 0.683 in normal livers, 0.754 in livers with stage F0 or F1 HF hepatic fibrosis , and 0.90 in livers with stage F2 or F3 HF hepatic fibrosis ; P < .001); however, they did not show significant correlation for stage F4 HF hepatic fibrosis (r = 0.30, P = .31). MR elastography and SWE shear-wave elastography showed similar diagnostic capability in depicting HF hepatic fibrosis of stage F2 or greater (P = .98) when LS liver stiffness measurements were reliably performed.
MR elastography and SWE shear-wave elastography showed moderate correlation and similar diagnostic performance in the diagnosis of HF hepatic fibrosis of stage F2 or greater; however, MR elastography yielded more reliable LS liver stiffness measurements than did SWE shear-wave elastography .
Purpose
To evaluate the efficacy of volumetric CT attenuation-based parameters obtained through automated 3D organ segmentation on virtual non-contrast (VNC) images from dual-energy CT (DECT) for ...assessing hepatic steatosis.
Materials and methods
This retrospective study included living liver donor candidates having liver DECT and MRI-determined proton density fat fraction (PDFF) assessments. Employing a 3D deep learning algorithm, the liver and spleen were automatically segmented from VNC images (derived from contrast-enhanced DECT scans) and true non-contrast (TNC) images, respectively. Mean volumetric CT attenuation values of each segmented liver (L) and spleen (S) were measured, allowing for liver attenuation index (LAI) calculation, defined as L minus S. Agreements of VNC and TNC parameters for hepatic steatosis, i.e., L and LAI, were assessed using intraclass correlation coefficients (ICC). Correlations between VNC parameters and MRI-PDFF values were assessed using the Pearson’s correlation coefficient. Their performance to identify MRI-PDFF ≥ 5% and ≥ 10% was evaluated using receiver operating characteristic (ROC) curve analysis.
Results
Of 252 participants, 56 (22.2%) and 16 (6.3%) had hepatic steatosis with MRI-PDFF ≥ 5% and ≥ 10%, respectively. L
VNC
and LAI
VNC
showed excellent agreement with L
TNC
and LAI
TNC
(ICC = 0.957 and 0.968) and significant correlations with MRI-PDFF values (r = − 0.585 and − 0.588, Ps < 0.001). L
VNC
and LAI
VNC
exhibited areas under the ROC curve of 0.795 and 0.806 for MRI-PDFF ≥ 5%; and 0.916 and 0.932, for MRI-PDFF ≥ 10%, respectively.
Conclusion
Volumetric CT attenuation-based parameters from VNC images generated by DECT, via automated 3D segmentation of the liver and spleen, have potential for opportunistic hepatic steatosis screening, as an alternative to TNC images.
To evaluate the diagnostic value of intravoxel incoherent motion (IVIM) diffusion-weighted (DW) magnetic resonance (MR) imaging in the quantitative assessment of the therapeutic efficacy of a ...vascular disrupting agent (VDA) (CKD-516) in rabbit VX2 liver tumors.
The institutional animal care and use committee approved this study. In 21 VX2 liver tumor-bearing rabbits, IVIM DW imaging examinations were serially performed with a 3.0-T imaging unit by using 12 b values from 0 to 800 sec/mm(2). The apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudodiffusion coefficient (D*), perfusion fraction (f), and blood flow-related parameter (fD*) of tumors at different time points (baseline, 4 hours, 24 hours, 3 days, and 7 days after CKD-516 administration) were compared within the treated group (n = 15) by using the Friedman test as well as between the control (n = 6) and treated groups by using the Mann-Whitney test. Correlation between the change in tumor size and IVIM DW imaging parameters was analyzed by using the Spearman rank test.
In the treated group, D* and f significantly decreased at 4 hours and then recovered to baseline at 24 hours, while D significantly increased at 24 hours (P < .005). All IVIM-derived parameters showed no significant differences between the control and treated groups at 3- and at 7-day follow-up. The greater decrease observed in f and fD* at 4 hours correlated with the smaller increase in tumor size during the 7 days of follow-up (ρ = 0.53 and 0.65, respectively; P < .05 for both).
The therapeutic effect induced by a VDA could be effectively evaluated by using IVIM DW imaging, and f and fD* may be early predictive indicators of tumor response.
Magnetic resonance imaging (MRI) using gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DPTA), or gadoxetic acid for short, is a hepatocyte-specific contrast agent which is now ...increasingly used for the detection and characterization of focal hepatic lesions, particularly in patients at high-risk of developing hepatocellular carcinomas (HCC). In fact, several recent guidelines now recognize gadoxetic acid-enhanced MRI (Gd-EOB-MRI) as the primary diagnostic imaging modality for the noninvasive diagnosis of HCC, although it must be noted that several major guidelines still include only extracellular contrast media-enhanced computed tomography and MRI. The primary merits of Gd-EOB-MRI lie in the fact that it can provide not only dynamic imaging, but also hepatobiliary phase (HBP) imaging which can lead to high lesion-to-liver contrast and give additional information regarding hepatocyte uptake via organic anion transporting polypeptides. This, in turn, allows higher sensitivity in detecting small HCCs and helps provide additional information regarding the multistep process of hepatocarcinogenesis. Indeed, many recent studies have investigated the diagnostic value of Gd-EOB-MRI for early HCCs as well as its role as a potential imaging biomarker in predicting outcome. We herein review the recent advances in the imaging diagnosis of HCCs focusing on the applications of Gd-EOB-MRI and the challenging issues that remain.
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