Hepatic hemangioma: atypical appearances on CT, MR imaging, and sonography

Accuracy of contrast-enhanced CT in liver neoplasms in children under 2 years age

BACKGROUND

Multiple differentials exist for pediatric liver tumors under 2 years. Accurate imaging diagnosis may obviate the need for tissue sampling in most cases.

OBJECTIVE

To evaluate the imaging features and diagnostic accuracy of computed tomography (CT) in liver tumors in children under 2 years.

METHODS

Eighty-eight children under 2 years with treatment naive liver neoplasms and baseline contrast-enhanced CT were included in this institutional review board approved retrospective study. Two blinded onco-radiologists assessed these tumors in consensus. Findings assessed included enhancement pattern, lobulated appearance, cystic change, calcifications, central scar-like appearance, and metastases. The radiologists classified the lesion as hepatoblastoma, infantile hemangioma, mesenchymal hamartoma, rhabdoid tumor, or indeterminate, first based purely on imaging and then after alpha-fetoprotein (AFP) correlation. Multivariate analysis and methods of comparing means and frequencies were used for statistical analysis wherever applicable. Diagnostic accuracy, sensitivity, and positive predictive values were analyzed.

RESULTS

The mean age of the sample was 11.4 months (95% CI, 10.9-11.8) with 50/88 (57%) boys. The study included 72 hepatoblastomas, 6 hemangiomas, 4 mesenchymal hamartomas, and 6 rhabdoid tumors. Presence of calcifications, multilobular pattern of arterial enhancement, lobulated morphology, and central scar-like appearance was significantly associated with hepatoblastomas (P-value < 0.05). Fourteen out of eighty-eight lesions were called indeterminate based on imaging alone; six lesions remained indeterminate after AFP correlation. Pure radiology-based diagnostic accuracy was 81.8% (95% CI, 72.2-89.2%), which increased to 92.1% (95% CI, 84.3-96.7%) (P-value > 0.05) after AFP correlation, with one hepatoblastoma misdiagnosed as a rhabdoid tumor. If indeterminate lesions were excluded for biopsy, the accuracy would be 98.8% (95% CI, 93.4-99.9%).

CONCLUSION

CT had high accuracy for diagnosing liver neoplasms in the under 2-year age population after AFP correlation. Certain imaging features were significantly associated with the diagnosis of hepatoblastoma. A policy of biopsying only indeterminate lesions after CT and AFP correlation would avoid sampling in the majority of patients.

Effectiveness of deep learning-based reconstruction for improvement of image quality and liver tumor detectability in the hepatobiliary phase of gadoxetic acid-enhanced magnetic resonance imaging

PURPOSE

To evaluate the effectiveness of deep learning-based reconstruction (DLR) in improving image quality and tumor detectability of isovoxel high-resolution breath-hold fat-suppressed T1-weighted imaging (HR-BH-FS-T1WI) in the hepatobiliary phase (HBP) of Gadoxetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI).

MATERIALS AND METHODS

This retrospective evaluated 42 patients with 98 liver tumors who underwent Gd-EOB-MRI between March 2023 and May 2023 using three techniques based on HBP imaging: isovoxel HR-BH-FS-T1WI reconstructed (1) with DLR (BH-DLR +) and (2) without DLR (BH-DLR -) and (3) HR-FS-T1WI scanned with a free-breathing technique using a navigator-echo-triggered technique and DLR (Navi-DLR +). The three techniques were qualitatively and quantitatively compared by the Friedman test and the Bonferroni post-hoc test. Tumor detectability was compared using the McNemar test.

RESULTS

BH-DLR + (3.85, average score of two radiologists) showed significantly better qualitative scores for image noise than BH-DLR - (2.84) and Navi-DLR + (3.37) (p < 0.0167), and Navi-DLR + showed significantly better scores than BH-DLR - (p < 0.0167). BH-DLR + (3.77) and BH-DLR - (3.77) showed significantly better qualitative scores for respiratory motion artifact than Navi-DLR + (2.75) (p < 0.0167), but there was no significant difference in scores between BH-DLR + and BH-DLR - (p > 0.0167). BH-DLR + (0.32) and Navi-DLR + (0.33) showed significantly higher lesion-to-nonlesion CR than BH-DLR - (0.29) (p < 0.0167), but there was no significant difference in lesion-to-nonlesion CR between BH-DLR + and Navi-DLR + (p > 0.0167). BH-DLR + (89.8%) showed significantly better tumor detectability than BH-DLR - (76.0%) and Navi-DLR + (77.6%) (p < 0.05).

CONCLUSION

The use of DLR for isovoxel HR-BH-FS-T1WI was effective in improving image quality and tumor detectability.

Improving liver lesions classification on CT/MRI images based on Hounsfield Units attenuation and deep learning

The early sign detection of liver lesions plays an extremely important role in preventing, diagnosing, and treating liver diseases. In fact, radiologists mainly consider Hounsfield Units to locate liver lesions. However, most studies focus on the analysis of unenhanced computed tomography images without considering an attenuation difference between Hounsfield Units before and after contrast injection. Therefore, the purpose of this work is to develop an improved method for the automatic detection and classification of common liver lesions based on deep learning techniques and the variations of the Hounsfield Units density on computed tomography scans. We design and implement a multi-phase classification model developed on the Faster Region-based Convolutional Neural Networks (Faster R-CNN), Region-based Fully Convolutional Networks (R-FCN), and Single Shot Detector Networks (SSD) with the transfer learning approach. The model considers the variations of the Hounsfield Unit density on computed tomography scans in four phases before and after contrast injection (plain, arterial, venous, and delay). The experiments are conducted on three common types of liver lesions including liver cysts, hemangiomas, and hepatocellular carcinoma. Experimental results show that the proposed method accurately locates and classifies common liver lesions. The liver lesions detection with Hounsfield Units gives high accuracy of 100%. Meanwhile, the lesion classification achieves an accuracy of 95.1%. The promising results show the applicability of the proposed method for automatic liver lesions detection and classification. The proposed method improves the accuracy of liver lesions detection and classification compared with some preceding methods. It is useful for practical systems to assist doctors in the diagnosis of liver lesions. In our further research, an improvement can be made with big data analysis to build real-time processing systems and we expand this study to detect lesions from all parts of the human body, not just the liver.

Deep Learning for Approaching Hepatocellular Carcinoma Ultrasound Screening Dilemma: Identification of α-Fetoprotein-Negative Hepatocellular Carcinoma From Focal Liver Lesion Found in High-Risk Patients

Background

First-line surveillance on hepatitis B virus (HBV)-infected populations with B-mode ultrasound is relatively limited to identifying hepatocellular carcinoma (HCC) without elevated α-fetoprotein (AFP). To improve the present HCC surveillance strategy, the state of the art of artificial intelligence (AI), a deep learning (DL) approach, is proposed to assist in the diagnosis of a focal liver lesion (FLL) in HBV-infected liver background.

Methods

Our proposed deep learning model was based on B-mode ultrasound images of surgery that proved 209 HCC and 198 focal nodular hyperplasia (FNH) cases with 413 lesions. The model cohort and test cohort were set at a ratio of 3:1, in which the test cohort was composed of AFP-negative HBV-infected cases. Four additional deep learning models (MobileNet, Resnet50, DenseNet121, and InceptionV3) were also constructed as comparative baselines. To evaluate the models in terms of diagnostic power, sensitivity, specificity, accuracy, confusion matrix, F1-score, and area under the receiver operating characteristic curve (AUC) were calculated in the test cohort.

Results

The AUC of our model, Xception, achieved 93.68% in the test cohort, superior to other baselines (89.06%, 85.67%, 83.94%, and 78.13% respectively for MobileNet, Resnet50, DenseNet121, and InceptionV3). In terms of diagnostic power, our model showed sensitivity, specificity, accuracy, and F1-score of 96.08%, 76.92%, 86.41%, and 87.50%, respectively, and PPV, NPV, FPR, and FNR calculated from the confusion matrix were respectively 80.33%, 95.24%, 23.08%, and 3.92% in identifying AFP-negative HCC from HBV-infected FLL cases. Satisfactory robustness of our proposed model was shown based on 5-fold cross-validation performed among the models above.

Conclusions

Our DL approach has great potential to assist B-mode ultrasound in identifying AFP-negative HCC from FLL found in surveillance of HBV-infected patients.

Morphological, dynamic and functional characteristics of liver pseudolesions and benign lesions

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide and one of the most common causes of death among patients with cirrhosis, developing in 1-8% of them every year, regardless of their cirrhotic stage. The radiological features of HCC are almost always sufficient for reaching the diagnosis; thus, histological confirmation is rarely needed. However, the study of cirrhotic livers remains a challenge for radiologists due to the developing of fibrous and regenerative tissue that cause the distortion of normal liver parenchyma, changing the typical appearances of benign lesions and pseudolesions, which therefore may be misinterpreted as malignancies. In addition, a correct distinction between pseudolesions and malignancy is crucial to allow appropriate targeted therapy and avoid treatment delays.The present review encompasses technical pitfalls and describes focal benign lesions and pseudolesions that may be misinterpreted as HCC in cirrhotic livers, providing the imaging features of regenerative nodules, large regenerative nodules, siderotic nodules, hepatic hemangiomas (including rapidly filling and sclerosed hemangiomas), segmental hyperplasia, arterioportal shunts, focal confluent fibrosis and focal fatty changes. Lastly, the present review explores the most promising new imaging techniques that are emerging and that could help radiologists differentiate benign lesions and pseudolesions from overt HCC.

Abdominal Organ Enhancement in Dynamic MRI using 1 M Gadobutrol vs 0.5 M Meglumine Gadoterate in Liver of Hemangioma Patients

BACKGROUND

The utility of gadobutrol (GAD) which is higher r1 value contrast media for evaluating abdominal solid organ have not been fully evaluated.

OBJECTIVE

To compare the contrast enhancement of abdominal organs on dynamic MRI using 0.1 mmol/kg 1.0 M GAD or 0.5 M meglumine gadoterate (MG) in patients with a liver hemangioma.

METHODS

A phantom study was performed at different concentrations (0.05, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0, 5.0 and 10 mmol/L) of GAD and MG. Sixty-two patients with a liver hemangioma were enrolled. Contrast media was injected at a rate of 2 mL/s followed by 40 mL of saline. Two arterial phases, a portal phase and an equilibrium phase were obtained. One certified radiologist set regions of interest on the abdominal aorta, liver, pancreas, spleen and the liver hemangioma. The relative enhancement ratio (RER) was calculated.

RESULTS

In the phantom study the signal intensity of both contrast media was similar at lower concentrations. However, the signal intensity of MG was higher at concentrations of more than 5.0 mmol/L. In the clinical study the RER of the abdominal viscera during the portal and equilibrium phases was higher with GAD. The hemangioma had a higher equilibrium phase enhancement with GAD. The aortic RER was equivalent during all phases and the liver RER during the 2nd arterial phase was higher with GAD. The arterial phase during GAD imaging might have been measured later than was optimal.

CONCLUSION

When the same injection protocol was used for an abdominal dynamic MRI, arterial phase imaging was late when GAD was used. The higher T1 relaxation value was significantly higher in the abdominal viscera during the portal and equilibrium phases, while the liver hemangioma also had significantly higher contrast enhancement during the equilibrium phase.

CLINICAL TRIAL REGISTRATION NUMBER

3186.

Incidental Liver Findings on Cross-sectional Imaging

Hepatic incidental findings often are seen on cross-sectional imaging examinations of the chest, spine, pelvis, or other nondedicated hepatic imaging. Radiologists are tasked with appropriately triaging, which requires further evaluation, even in the setting of an otherwise limited evaluation. This article reviews common benign entities encountered on ultrasound, computed tomography, or magnetic resonance imaging, along with their characteristic imaging features. Imaging features that are suspicious for malignancy or suggest the need for further evaluation also are discussed. Two algorithms are proposed to guide radiologists in their recommendations based on patient risk factors, focal hepatic abnormality size, and available imaging features.

Hepatic sclerosed hemangioma and sclerosing cavernous hemangioma: a radiological study

Purpose

To investigate and compare the CT and MRI features of hepatic sclerosed hemangioma (HSH) and sclerosing cavernous hemangioma (SCH).

Materials and methods

Twelve HSH cases and 36 SCH cases were included, the imaging findings on CT (9 HSH and 34 SCH) and MRI (8 HSH and 10 SCH) were analyzed. Qualitative image analysis included the location, size, shape, capsular retraction, density, calcification, signal intensity on T₁-weighted image (T₁WI) and T₂-weighted image (T₂WI), presence of diffusion restriction, apparent diffusion coefficient (ADC) map, transient hepatic attenuation difference around the lesion, and the dynamic enhancement patterns.

Results

The presence of liver cirrhosis in patients with HSH (3/12) was higher than SCH (1/36) (P = 0.043). The morphology appearance before enhancement showed no significant difference between HSH and SCH. Moreover, SCH had a stronger trend of centripetal enhancement patterns of cavernous hemangiomas (83.3%) compared to HSH (25%) (P < 0.001). Due to more frequent atypical enhancement features, containing rim-like enhancement, no enhancement, and peripheral heterogeneous enhancement, the misdiagnosis rate of HSH (75%) was significantly higher than that of SCH (16.7%) (P < 0.001). Furthermore, the ADC values of HSH and SCH were both higher than that of the surrounding liver parenchyma (P = 0.009, P = 0.002); however, there was no significant difference in ADC values between themselves (P = 0.613).

Conclusion

SCH showed the same trend of centripetal enhancement characteristics as typical hemangioma, while HSH exhibited atypical enhancement features due to complete sclerosis. Higher ADC values might contribute to the identification of atypical HSH and SCH from malignancies.

Differentiating Liver Hemangioma from Metastatic Tumor Using T2-enhanced Spin-echo Imaging with a Time-reversed Gradient-echo Sequence in the Hepatobiliary Phase of Gadoxetic Acid-enhanced MR Imaging

Purpose: To evaluate the utility of T2-enhanced spin-echo imaging using the time-reversed gradient echo sequence (T2FFE imaging) in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI (Gd-EOB-MRI) for differentiating hemangiomas from metastatic tumors.

Methods: A total of 61 patients with 133 liver lesions, including 37 hemangiomas and 96 metastatic tumors, were scanned by Gd-EOB-MRI. Four data sets were independently analyzed by two readers: (1) 3D fat-suppressed T2-weighted imaging (FS-T2WI) alone; (2) the combination of 3D FS-T2WI and T2FFE imaging in the HBP of Gd-EOB-MRI; (3) the combination of 3D FS-T2WI, diffusion-weighted imaging (DWI) with the b-value of 1000 s/mm² and the apparent diffusion coefficient (ADC); and (4) a dynamic study of Gd-EOB-MRI. After classifying the lesion sizes as ≤ 10 mm or > 10 mm, we conducted a receiver-operating characteristic analysis to compare diagnostic accuracies among the four data sets for differentiating hemangiomas from metastatic tumors.

Results: The areas under the curves (AUCs) of the four data sets of two readers were: (1) ≤ 10 mm (0.85 and 0.91) and > 10 mm (0.88 and 0.97), (2) ≤ 10 mm (0.94 and 0.94) and > 10 mm (0.96 and 0.95), (3) ≤ 10 mm (0.90 and 0.87) and > 10 mm (0.89 and 0.95), and (4) ≤ 10 mm (0.62 and 0.67) and > 10 mm (0.76 and 0.71), respectively. Data sets (2) and (3) showed no significant differences in AUCs, but both showed significantly higher AUCs compared to that of (4) regardless of the lesion size (P < 0.05).

Conclusion: The combination of 3D FS-T2WI and T2FFE imaging in the HBP of Gd-EOB-MRI achieved an accuracy equivalent to that of the combination of 3D FS-T2WI, DWI, and ADC and might be helpful in differentiating hemangiomas from metastatic tumors.

Multilocular cystic hemangioma of the liver mimicking mucinous cystic neoplasm

Hepatic hemangiomas infrequently exhibit atypical imaging features, which may cause diagnostic confusion with hepatic malignancies and lead to unnecessary surgery. We report a rare case of multilocular cystic hemangioma of the liver mimicking a mucinous cystic neoplasm of the liver in a 48-year-old female, focusing on computed tomography and magnetic resonance imaging features and their differential diagnosis.

The humbling hemangioma: uncommon CT and MRI imaging features and mimickers of hepatic hemangiomas

Cavernous hemangiomas are among the most common liver lesions encountered in abdominal imaging. While classical imaging characteristics usually aid the radiologist in confidently arriving at its diagnosis, atypical hemangiomas can prove to be difficult to distinguish from other more worrisome hepatic lesions such as metastases and hepatocellular carcinoma. Furthermore, some malignant lesions can display features that simulate hemangiomas. The radiologist must be aware of these pitfalls to make an accurate diagnosis, when possible.

Imaging-based diagnosis of benign lesions and pseudolesions in the cirrhotic liver

Liver cirrhosis is a leading cause of death worldwide, with 1-year mortality rates of up to 57% in decompensated patients. Hepatocellular carcinoma (HCC) is the most common primary tumor in cirrhotic livers and the second leading cause of cancer-related mortality worldwide. Annually, up to 8% of patients with cirrhosis develop HCC. The diagnosis of HCC rarely requires histological confirmation: in fact, according to the most recent guidelines, the imaging features of HCC are almost always sufficient for a certain diagnosis. Thus, the role of the radiologist is pivotal because the accurate detection and characterization of focal liver lesions in patients with cirrhosis are essential in improving clinical outcomes. Despite recent technical innovations in liver imaging, several issues remain for radiologists regarding the differentiation of HCC from other hepatic lesions, particularly benign lesions and pseudolesions. It is important to avoid misdiagnosis of benign liver lesions as HCC (false-positive cases) because this diagnostic misinterpretation may lead to ineligibility of a patient for potentially curative treatments or inappropriate assignment of high priority scores to patients on waiting lists for liver transplantation. This review presents a pocket guide that could be useful for the radiologist in the diagnosis of benign lesions and pseudolesions in cirrhotic livers, highlighting the imaging features that help in making the correct diagnosis of macroregenerative nodules; siderotic nodules; arterioportal shunts; hemangiomas, including fast-filling hemangiomas, hemangiomas with pseudowashout, and sclerosed hemangiomas; confluent fibrosis; pseudomasses in chronic portal vein thrombosis; and focal fatty changes.

The value of multiparametric histogram features based on intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) for the differential diagnosis of liver lesions

Background

The present study analyzed whole-lesion histogram parameters from intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) to explore the clinical value of IVIM histogram features in the differentiation of liver lesions.

Methods

In this retrospective study, 33 cases of hepatic hemangioma (HH), 22 cases of hepatic cysts (HC), and 34 cases of hepatocellular carcinoma (HCC) were underwent IVIM-DWI (b =0–600 s/mm²), which were confirmed pathologically and clinically. The data were processed by IVIM model to obtain the following quantitative indicators: perfusion fraction (f), slow diffusion coefficient (D), and pseudo-diffusion coefficient (or fast diffusion coefficient, D*). The region of interest in the largest solid part of the lesion was delineated for histogram analysis of the correlation between tissue image and lesion type. The relevant histogram parameters were obtained and statistically analyzed. The characteristic histogram parameters for HH, HC, and HCC were compared to find significantly different parameters. The diagnostic efficacies of these parameters for HH, liver cysts, and HCC were assessed using the receiver operating characteristic (ROC) curves.

Results

There were significant differences in the maximum diameter, maximum value, minimum value, mean, median, standard deviation, uniformity, skewness, kurtosis, volume, 10th percentile (P10) of D, and 90th percentile (P90) of D between the three groups (P<0.05). The maximum diameter, minimum value, entropy, and volume of D* differed significantly between the three groups (P<0.05). The maximum diameter, minimum value, mean, median, skewness, kurtosis, volume, P10, and P90 of f differed significantly between the three groups (P<0.05). The largest area under the ROC curve (AUC) for both D* and f was that of volume (AUC =0.883 for both). When 1438.802 was used as the volume cut-off, the sensitivity and specificity of volume in differentiating between HH and HC were 87.88 and 77.27, respectively, and the sensitivity and specificity of volume in differentiating between HC and HCC were 77.27 and 85.29.

Conclusions

A multiparametric histogram from IVIM-DWI magnetic resonance imaging (MRI) is an effective means of identifying HH, HC, and HCC that provides valuable reference information for clinical diagnosis.

Comparison of the Enhancement Pattern of Hepatic Hemangioma on Magnetic Resonance Imaging Performed With Gd-EOB-DTPA Versus Gd-BOPTA

PURPOSE

To compare magnetic resonance imaging (MRI) findings with gadoxetic acid and gadobenate dimeglumine for the diagnosis of hepatic hemangiomas.

MATERIALS AND METHODS

In this retrospective study, we included 26 hemangiomas (mean size was 14 mm ± 10 mm) in 19 patients (mean age 60 ± 14 years) scanned with both gadobenate dimeglumine MRI and gadoxetic acid MRI. For each patient, we collected multiple lesion variables including location, number, size and enhancement pattern on arterial, portal venous, 3-minute and hepatobiliary phases with both gadoxetic acid and gadobenate dimeglumine. The enhancement pattern with the two contrast agents was then compared.

RESULTS

The typical enhancement pattern of hepatic hemangiomas was more common-though not statistically significant-with gadobenate dimeglumine compared to gadoxetic acid (57% [15 of 26] vs 42% [11 of 26], respectively; P = 0.4057 for both peripheral globular discontinuous enhancement in the arterial phase and centripetal fill-in in the portal venous phase). A significantly higher number of hemangiomas showed centripetal fill-in or hyperintensity in the 3-minute phase with gadobenate dimeglumine compared to gadoxetic acid (88% [23 of 26) vs 58% [15 of 26]; P = 0.0266). A pseudo washout sign in the 3-minute phase was detected in one of the 5 flash-filling hemangiomas with gadoxetic acid, but not gadobenate dimeglumine. All hemangiomas were hypointense in the hepatobiliary phase with both gadobenate dimeglumine and gadoxetic acid.

CONCLUSIONS

The enhancement pattern of hepatic hemangiomas may vary depending on the hepatobiliary agent, with more frequent lack of the typical pattern with gadoxetic acid compared to gadobenate dimeglumine.

Uncommon evolutions and complications of common benign liver lesions

Frequently encountered on abdominal imaging studies, the majority of common benign liver lesions are asymptomatic, confidently diagnosed by imaging, and do not require further workup, follow-up, or treatment. The increasing use of multimodality liver imaging, has allowed the recognition of uncommon evolutions of common benign liver lesions such as size changes, fibrotic regression, and content and vascularization changes, and their complications such as rupture, hemorrhage, thrombosis, extrinsic compression, and malignancy. The purpose of this pictorial review is to describe and illustrate the incidence and diagnostic features of these uncommon evolutions and complications on cross-sectional imaging, mainly on computed tomography and magnetic resonance imaging, with emphasis on those imaging clues which are helpful in the differential diagnosis or indicate the need for treatment.

Preoperative diagnosis of the sclerosed hemangioma of the liver using multimodality imaging findings: A case report

A sclerosed hemangioma of the liver is a rare benign lesion characterized by fibrosis and hyalinization of a hepatic cavernous hemangioma as a result of degeneration. This condition has been difficult to correctly diagnose with imaging. Our patient was a 57-year-old man whose computed tomography (CT) scan showed a mass of 45 mm in diameter in the lateral segment. On dynamic contrast-enhanced CT, the lesion was found to comprise peripheral, gradual, and heterogeneous enhanced areas with a central nonenhanced area; malignancy was suspected. On magnetic resonance imaging, the peripheral area showed slight hperintensity on T2-weighted image, and showed a similar intensity on T1- and diffusion-weighted images as compared to the background liver and gradual enhancement, and the presence of abundant fibrous tissue was suspected. Conversely, the central area showed remarkable hyperintensity on T2-weighted images and no enhancement, and degeneration or hyalinization was suspected. The mass showed no uptake of fluorine-18 fludeoxyglucose (FDG). Some imaging findings suspected a benign tumor, and sclerosed hemangioma with abundant fibrosis and hyalinization was pathologically confirmed. Herein, we report a case of sclerosed hemangioma focusing on possible preoperative diagnosis using a combination of multimodality imaging findings—diffusion-weighted imaging and FDG-positron emission tomography imaging.

Primary Hepatic Neoplasms of Vascular Origin: Key Imaging Features and Differential Diagnoses With Radiology-Pathology Correlation

OBJECTIVE

This article describes, illustrates, and correlates imaging and pathologic features of primary vascular mesenchymal neoplasms of the liver, which arise from the vascular endothelium and perivascular epithelioid cells.

CONCLUSION

Familiarity with the spectrum of benign, malignant-potential and malignant vascular neoplasms, and nonneoplastic mimickers allows consideration in the differential diagnosis of enhancing hepatic masses. Understanding relevant pathologic features facilitates recognition of key imaging features, specifically dynamic contrast enhancement patterns on CT and MRI, which provide a useful classification system.

Peritumoral Hyperplasia in Hepatic Sclerosed Hemangioma

Peritumoral hyperplasia (PTH) is a hyperplastic lesion located around hypervascular tumors. Hepatic sclerosed hemangioma is a very rare form of hemangioma with sclerotic changes and is distinct from sclerosing hemangioma. We present a patient with non-alcoholic steatohepatitis-induced cirrhosis who presented with a hypervascular tumor. The tumor showed atypical findings of hemangioma and was treated with surgical resection because hepatic malignancy could not be ruled out. Histopathologic examination revealed the tumor was a sclerosed hemangioma with PTH. Lesions with carcinogenic potential were found in the PTH lesion. Sclerosed hemangioma should be observed and managed carefully.

The diagnostic advantage of EOB-MR imaging over CT in the detection of liver metastasis in patients with potentially resectable pancreatic cancer

BACKGROUND

Liver metastases (LMs) are sometimes diagnosed intraoperatively, even when multidetector-row computed tomography (MDCT) reveals no LM in the staging of pancreatic cancer (PC). Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MR imaging) may have a role to play in the detection of LM.

METHODS

The present study included a total of 201 patients who underwent an EOB-MR imaging examination before undergoing surgical resection for pancreatic cancer that was determined to be radiologically-resectable by MDCT. Intrahepatic lesions that were considered suspected to be liver metastases following an EOB-MR imaging examination were defined as possible lesions (PLs). All PLs were evaluated by a pathological examination or through close follow-up examinations. The diagnostic ability of EOB-MR imaging was assessed. The predictive factors for liver metastasis were evaluated.

RESULTS

Thirty-seven PLs were noted in 17 patients: 31 PLs were true LMs, and six were benign lesions (3 hemangiomas and 3 abscesses). Nine LMs were newly detected during surgery and were not detected by preoperative EOB-MR imaging. The diagnostic ability of EOB-MR imaging was as follows: sensitivity, 77.5%; specificity, 94.7%; positive predictive value, 83.8%; negative predictive value, 92.3%; and accuracy, 90.2%. A multivariate analysis revealed that the presence of PL on EOB-MR imaging was the only independent risk factor for intraoperative liver metastasis (P < 0.001).

CONCLUSION

EOB-MR imaging was useful in detecting tiny liver metastases from pancreatic cancer in cases that were determined to be radiologically resectable by MDCT.

Contrast-Enhanced Ultrasound in Focal Liver Lesions: Where Do We Stand?

Contrast-enhanced ultrasound (CEUS) represents a significant breakthrough in sonography, and it is being increasingly used for the evaluation of focal liver lesions (FLLs). Currently, CEUS is included as a part of the suggested diagnostic workup of FLLs, resulting in a better patient management and delivering cost-effective therapy. After a brief technical note, contrast-enhancement patterns of different types of benign and malignant FLLs, along with hepatic pseudolesions, are described and discussed based on our experience and literature data. At the same time, the most recent concepts and the use of CEUS in different clinical settings are presented.

High-flow haemangiomas versus hypervascular hepatocellular carcinoma showing "pseudo-washout" on gadoxetic acid-enhanced hepatic MRI: value of diffusion-weighted imaging in the differential diagnosis of small lesions

AIM

To validate the usefulness of diffusion-weighted imaging (DWI) in the differentiation of high-flow haemangiomas showing pseudo-washout appearance on gadoxetic acid-enhanced hepatic MRI from small hypervascular hepatocellular carcinomas (HCCs).

MATERIALS AND METHODS

DWI (b=50, 800 s/mm²) with apparent diffusion coefficient (ADC) maps for 50 haemangiomas (6.4±2.9 mm) showing intense enhancement on arterial dominant phase imaging and hypointensity on transitional and/or hepatobiliary phase imaging during gadoxetic acid-enhanced MRI were retrospectively analysed and compared with that of 113 hypervascular HCCs (12.8±3.7 mm). In addition to measurement of mean ADC values on DWI and contrast-to-noise ratio (CNR) on corresponding T2-weighted imaging, qualitative analysis of DWI was performed for each lesion by two independent observers using a five-point scale.

RESULTS

Both of mean ADC value (1.902 versus 0.997×10^-3 mm²/s) and mean CNR (119.2 versus 36.9) for haemangioma were significantly larger than for HCC (p<0.001). On receiver operating characteristic (ROC) analysis, an area under the curve (AUC) of 0.995 for ADC values was significantly larger than 0.915 for CNRs (p=0.002). When the ADC value of 1.327×10^-3 mm²/s was used as the threshold for the diagnosis of haemangioma, the sensitivity and specificity were 98% and 97.3%, respectively. The mean sensitivity and specificity of qualitative analysis for the differentiation of haemangioma from HCC were 92% and 99.1%, respectively.

CONCLUSION

For high-flow small haemangiomas showing pseudo-washout appearance during gadoxetic acid-enhanced hepatic MRI, high b-factor DWI including an ADC map may provide additional information to enhance the confidence to exclude small hypervascular HCCs.

Primary mesenchymal liver tumors: radiological spectrum, differential diagnosis, and pathologic correlation

With the exception of hemangioma, benign or malignant primary mesenchymal tumors of the liver are seldom encountered. The aim of this review was to discuss the clinical, histopathological, and imaging features of liver hemangiomas (cavernous, capillary, and sclerosed types), liver lipoma, angiomyolipoma, mesenchymal hamartoma, neurofibroma, infantile hemangioendothelioma, epithelioid hemangioendothelioma, myofibroblastoma, angiosarcoma, malignant fibrous histiocytoma, undifferentiated embryonal sarcoma, and nested stromal tumor. In most of these rare liver tumors, radiological findings obtained by cross-sectional imaging may reflect the characteristic pathologic features required for differential diagnosis; however, definitive diagnosis should be confirmed using histopathological examination.

Free-breathing liver perfusion imaging using 3-dimensional through-time spiral generalized autocalibrating partially parallel acquisition acceleration

OBJECTIVES

The goal of this study was to develop free-breathing high-spatiotemporal resolution dynamic contrast-enhanced liver magnetic resonance imaging using non-Cartesian parallel imaging acceleration, and quantitative liver perfusion mapping.

MATERIALS AND METHODS

This study was approved by the local institutional review board and written informed consent was obtained from all participants. Ten healthy subjects and 5 patients were scanned on a Siemens 3-T Skyra scanner. A stack-of-spirals trajectory was undersampled in-plane with a reduction factor of 6 and reconstructed using 3-dimensional (3D) through-time non-Cartesian generalized autocalibrating partially parallel acquisition. High-resolution 3D images were acquired with a true temporal resolution of 1.6 to 1.9 seconds while the subjects were breathing freely. A dual-input single-compartment model was used to retrieve liver perfusion parameters from dynamic contrast-enhanced magnetic resonance imaging data, which were coregistered using an algorithm designed to reduce the effects of dynamic contrast changes on registration. Image quality evaluation was performed on spiral images and conventional images from 5 healthy subjects.

RESULTS

Images with a spatial resolution of 1.9 × 1.9 × 3 mm3 were obtained with whole-liver coverage. With an imaging speed of better than 2 s/vol, free-breathing scans were achieved and dynamic changes in enhancement were captured. The overall image quality of free-breathing spiral images was slightly lower than that of conventional long breath-hold Cartesian images, but it provided clinically acceptable or better image quality. The free-breathing 3D images were registered with almost no residual motion in liver tissue. After the registration, quantitative whole-liver 3D perfusion maps were obtained and the perfusion parameters are all in good agreement with the literature.

CONCLUSIONS

This high-spatiotemporal resolution free-breathing 3D liver imaging technique allows voxelwise quantification of liver perfusion.

Imaging findings of mimickers of hepatocellular carcinoma

Radiological imaging plays a crucial role in the diagnosis of hepatocellular carcinoma (HCC) as the noninvasive diagnosis of HCC in high-risk patients by typical imaging findings alone is widely adopted in major practice guidelines for HCC. While imaging techniques have markedly improved in detecting small liver lesions, they often detect incidental benign liver lesions and non-hepatocellular malignancy that can be misdiagnosed as HCC. The most common mimicker of HCC in cirrhotic liver is nontumorous arterioportal shunts that are seen as focal hypervascular liver lesions on dynamic contrast-enhanced cross-sectional imaging. Rapidly enhancing hemangiomas can be easily misdiagnosed as HCC especially on MR imaging with liver-specific contrast agent. Focal inflammatory liver lesions mimic HCC by demonstrating arterial-phase hypervascularity and subsequent washout on dynamic contrast-enhanced imaging. It is important to recognize the suggestive imaging findings for intrahepatic cholangiocarcinoma (CC) as the management of CC is largely different from that of HCC. There are other benign mimickers of HCC such as angiomyolipomas and focal nodular hyperplasia-like nodules. Recognition of their typical imaging findings can reduce false-positive HCC diagnosis.

Transcatheter Arterial Embolization Alone for Giant Hepatic Hemangioma

Giant hepatic hemangioma is a benign liver condition that may be treated using surgery. We studied the digital subtraction angiographic (DSA) characteristics of giant hepatic hemangioma, and the effectiveness of transcatheter arterial embolization (TAE) alone for its treatment. This was a retrospective study of 27 patients diagnosed with giant hepatic hemangioma and treated with TAE alone (using lipiodol mixed with pingyangmycin) at the Division of Hepatobiliary and Pancreatic Surgery, First Affiliated Hospital, Zhejiang University, between January 2010 and March 2013. The feeding arteries were identified using DSA. All patients were followed up for between three weeks and 12 months. Changes in tumor diameter and symptoms were observed. The 27 patients included had giant hepatic hemangiomas ranging from 5.3 to 24.5 cm (mean, 11.24±5.08 cm) in the right (n = 13), left (n = 1) or both (n = 13) lobes. Preoperative hepatic angiography showed multiple abnormal vascular lakes in the early phase, known as the “early leaving but late returning, hanging nut on a twig” sign. On the day after TAE, hepatic transaminase levels were increased (ALT: 22.69±17.95 to 94.88±210.32 U/L; ALT: 24.00±12.37 to 99.70±211.54 U/L; both P<0.05), but not total bilirubin. Six patients complained of abdominal pain, and 12 experienced transient fever. In the months after TAE, tumor size decreased (baseline: 11.24±5.08; 3 months: 8.95±4.33; 6 months: 7.60±3.90 cm; P<0.05), and the patients’ condition improved. These results indicated that TAE was effective and safe for treating giant hepatic hemangioma. TAE may be a useful alternative to surgery for the treatment of hepatic hemangioma.

Clinical Translation of an Albumin-Binding PET Radiotracer 68Ga-NEB

Suitably labeled Evans blue dye has been successfully applied to evaluate cardiac function, vascular permeability, and lymphatic imaging in preclinical settings. This study documented the first-in-human application of 68Ga-1,4,7-triazacyclononane-N,N',N″-triacetic acid (NOTA)-NEB.

METHODS

The NOTA-conjugated truncated form of Evans blue, NEB, was labeled with 68Ga and tested in BALB/C mice for dynamic PET and ex vivo biodistribution studies. Three healthy volunteers (2 men and 1 woman) underwent 90-min whole-body dynamic PET. The absorbed doses for major organs and whole body were calculated using OLINDA/EXM software. Eleven patients with focal hepatic lesions diagnosed by enhanced CT or MR imaging were subjected to whole-body PET/CT acquisitions at 30 min after intravenous injection of 111-148 MBq (3-4 mCi) of 68Ga-NEB.

RESULTS

NEB dye was labeled with 68Ga (half-time, 68 min) with high yield and purity. After intravenous injection, 68Ga-NEB formed a complex with serum albumin, thus most of the radioactivity was retained in blood circulation. The tracer was demonstrated to be safe in both healthy volunteers and recruited patients without side effects or allergies. Among the 11 patients, hemangiomas showed much higher 68Ga-NEB signal intensity than the surrounding normal hepatic tissues, whereas no apparent difference between lesions and hepatic tissues was identified on 18F-FDG PET. All other focal hepatic lesions including hepatocellular carcinoma, hepatic cysts, and neuroendocrine tumor liver metastases showed negative 68Ga-NEB contrast to hepatic tissues.

CONCLUSION

As a blood-pool imaging agent, 68Ga-NEB is safe to use in the clinic, and our preliminary studies demonstrate the value of differentiating hepatic hemangioma from other benign or malignant focal hepatic lesions. Easy labeling with different positron emitters of various half-lives, excellent pharmacokinetics, and imaging quality warrant further clinical applications of NEB-based PET tracers.

Imaging features of subcentimeter hypointense nodules on gadoxetic acid-enhanced hepatobiliary phase MR imaging that progress to hypervascular hepatocellular carcinoma in patients with chronic liver disease

BACKGROUND

With the advent of 3-T magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI), many subcentimeter hepatic nodules have been frequently detected in patients with chronic liver disease, and the prediction of subcentimeter nodules that progress to hypervascular hepatocellular carcinoma (HCC) is important.

PURPOSE

To reveal the imaging features of subcentimeter hypointense nodules on gadoxetic acid-enhanced hepatobiliary phase MR images in patients with chronic liver disease that may be related with progression to hypervascular HCC.

MATERIAL AND METHODS

This study included 109 patients with 135 subcentimeter hypointense nodules (103 hepatocellular carcinomas [HCCs] and 32 benign nodules) on gadoxetic acid-enhanced hepatobiliary phase. For each subcentimeter nodule, the following imaging features were analyzed: (i) hyperintensity on T2-weighted (T2W) image or DWI; (ii) arterial hypervascularization; and (iii) hypointensity on a portal or late phase. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of those imaging features for predicting subcentimeter nodules that progressed to hypervascular HCC were evaluated. Volume doubling time (VDT) of subcentimeter nodules that progressed to hypervascular HCC was compared to that of growing benign nodules.

RESULTS

Arterial hypervascularization with washout yielded the highest specificity (90.6%) and PPV (95.4%) for prediction of subcentimeter nodules that progressed to hypervascular HCC. Combining hyperintensity on T2W image or DWI and arterial hypervascularization with washout did not raise the specificity (90.6%) for prediction of subcentimeter nodules that progressed to hypervascular HCC. Mean VDT (112.2 ± 106.3 days) of subcentimeter nodules that progressed to hypervascular HCC during follow-up was significantly shorter than those of benign subcentimeter nodules (1258 ± 766.5 days, P < 0.001).

CONCLUSION

Arterial hypervascularization with washout in subcentimeter hypointense nodules on gadoxetic acid-enhanced hepatobiliary phase in patients with chronic liver disease is strongly related with progression to hypervascular HCC.

The ins and outs of liver imaging

Different imaging modalities including ultrasonography, computed tomography (CT), and MR imaging may be used in the liver depending on the clinical situation. The ability of dedicated contrast-enhanced liver MR imaging or CT to definitively characterize lesions as benign is crucial in avoiding unnecessary biopsy. Liver imaging surveillance in patients with cirrhosis may allow for detection of hepatocellular carcinoma at an earlier stage, and therefore may improve outcome. This article reviews the different imaging modalities used to evaluate the liver and focal benign and malignant hepatic lesions, and the basic surveillance strategy for patients at increased risk for hepatocellular carcinoma.

MR imaging of benign focal liver lesions

Focal liver lesions (FLLs) are commonly encountered on routine imaging studies. Most lesions detected are benign, but many are indeterminate at the time of initial imaging. This article reviews the important role of MR imaging for the detection and characterization of various benign FLLs while illustrating typical imaging appearances and potential pitfalls in interpretation. The utility of diffusion-weighted imaging and hepatocyte-specific contrast agents is also discussed.

Magnetic resonance imaging in cirrhosis: what's new?

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

Hepatic haemangioma: common and uncommon imaging features

The haemangioma, the most common non-cystic hepatic lesion, most often discovered by chance, may in certain situations raise diagnostic problems in imaging. In this article, the authors first demonstrate that the radiological appearance of the hepatic haemangioma, in its typical form, is closely related to three known histological sub-types. They then show that certain atypical features should be known in order to establish a diagnosis. They also observe the potential interactions between the haemangioma, an active vascular lesion, and the adjacent hepatic parenchyma. Finally, they discuss the specific paediatric features of hepatic haemangiomas and illustrate the case of a hepatic angiosarcoma.

Characterization of incidental liver lesions: comparison of multidetector CT versus Gd-EOB-DTPA-enhanced MR imaging

As a result of recent developments in imaging modalities and wide spread routine medical checkups and screening, more incidental liver lesions are found frequently on US these days. When incidental liver lesions are found on US, physicians have to make a decision whether to just follow up or to undergo additional imaging studies for lesion characterization. In order to choose the next appropriate imaging modality, the diagnostic accuracy of each imaging study needs to be considered. Therefore, we tried to compare the accuracy of contrast-enhanced multidetector CT (MDCT) and Gd-EOB-DTPA-enhanced MRI for characterization of incidental liver masses. We included 127 incidentally found focal liver lesions (94 benign and 33 malignant) from 80 patients (M∶F = 45∶35) without primary extrahepatic malignancy or chronic liver disease. Two radiologists independently reviewed Gd-EOB-DTPA-enhanced MRI and MDCT. The proportion of confident interpretations for differentiation of benign and malignant lesions and for the specific diagnosis of diseases were compared. The proportion of confident interpretations for the differentiation of benign and malignant lesions was significantly higher with EOB-MRI(94.5%-97.6%) than with MDCT (74.0%-92.9%). In terms of specific diagnosis, sensitivity and accuracy were significantly higher with EOB-MRI than with MDCT for the diagnosis of focal nodular hyperplasia (FNH) and focal eosinophilic infiltration. The diagnoses of the remaining diseases were comparable between EOB-MRI and MDCT. Hence, our results suggested that Gd-EOB-MRI may provide a higher proportion of confident interpretations than MDCT, especially for the diagnosis of incidentally found FNH and focal eosinophilic infiltration.

Gastrointestinal imaging: tips and traps in the diagnosis of small HCC

Improvement in survival of patients with HCC depends on detecting small lesions. This is possible by screening all patients with cirrhosis for HCC. However, these small lesions are difficult to characterise as only 50 to 80% of lesions less than 3cm have a typical HCC appearance, depending on the imaging technique used. MRI, with its various possibilities (dynamic sequences, diffusion-weighting, liver-specific contrast agents), is currently the most effective imaging technique for characterising these small HCCs, but at present we do not know the best combination of imaging examinations for diagnosing the condition.

Abdominal Hemangiomas: A Pictorial Review of Unusual, Atypical, and Rare Types

Hemangiomas are a radiologist's dream lesions because they allow a confident diagnosis most of the time. However, within the abdomen, hemangiomas may occur in such atypical locations and can have such unusual features that they cause significant diagnostic dilemma and may end up being excised surgically. The literature is replete with isolated case reports of atypical hemangiomas in the abdominal cavity, and, to our knowledge, so far, there is no comprehensive review. We present, in this article, a pictorial review of a gamut of uncommon hemangiomas and hemangiomatosis syndromes. Knowledge of these rare types can help in limiting diagnostic errors and increase the confidence of radiologists, thus avoiding unnecessary surgeries.

Colour Doppler ultrasound imaging findings in paediatric periocular and orbital haemangiomas

PURPOSE

To evaluate the combined grey-scale ultrasonography (US) and colour Doppler imaging (CDI) as the first and primary imaging modalities in diagnosing paediatric orbital haemangiomas.

METHODS

The charts of 20 consecutive children with a periorbital mass echographically diagnosed as a haemangioma between January 2004 and June 2009 in the Tel-Aviv Sourasky Medical Center were reviewed. Data on demographic details, clinical findings, US and CDI characteristics, treatment and outcome were retrieved.

RESULTS

Twelve (60%) haemangiomas were located on the upper eyelid, five in the lower eyelid (25%) and three in the medial cantus (15%). The tumour resolved completely in 10 children (50%) and in 10 children (50%) partial resolution was documented. Seven (35%) patients underwent treatment (intralesional or oral steroids or propranolol). Grey-scale US depicted a solid-tissue mass with low internal echogenicity. Mean haemangioma volume was 1.33 cm(3) . Colour Doppler imaging demonstrated intralesional flow with a mean peak systolic velocity of 15.2 cm per second and a mean resistance index of 0.51. All US and CDI examinations were carried out on alert children and no sedation or general anaesthesia was needed. During mean follow-up time of 23 months, no child required any additional imaging or diagnostic procedures to confirm the diagnosis.

CONCLUSION

Combined US and CDI are suggested as the first imaging modalities in cases with a suspected diagnosis of periocular and orbital capillary haemangioma.

Fading hepatic hemangiomas on multiphasic CT

PURPOSE

To describe fading hemangiomas [substantially lower attenuation (>30 HU) than vascular pool in the portal venous phase (PVP)] and to determine their incidence and characteristics on multiphasic CT.

METHODS

The study population composed of 168 hemangiomas (≥5 mm) in 114 consecutive patients which were imaged on multiphasic CT and also proved by diagnostic findings on MRI. The size of hemangiomas and CT attenuation number of the enhancing area within the hemangioma, liver parenchyma, and portal vein were measured on both arterial phase (AP) and PVP images. The rapidity of enhancement (slow, <50%; rapid, 50%-99%; flash-filler, 100% filling in the AP) and association with arterioportal shunting (APS) were also determined by two independent reviewers. Imaging features were compared between fading and non-fading hemangiomas using Kruskal-Wallis test.

RESULTS

Of 168 hemangiomas, the enhancing area of 27 hemangiomas (16%, 27/168) showed substantially lower attenuation than that of PV (fading) in the PVP. When the attenuation difference was compared with the rapidity of enhancement, flash-fillers showed lower attenuation than PV in the PVP more frequently than both slow-fillers (P < 0.05) and rapid-fillers (P < 0.05). The proportion of fading hemangiomas was 52% (14/27) in flash-fillers, much more frequent than in rapid-fillers (4/27, 15%) as well as slow-fillers (9/27, 33.3%). The size of fading hemangiomas (17.9 ± 4.5 mm) was significantly smaller than that of non-fading (24.2 ± 3.6 mm) (P = 0.032). Although APS was more frequent in fading hemangiomas (55.6%, 15/27) than that of non-fading hemangiomas (37.6%, 53/141), there was no statistically significant difference (P = 0.086).

CONCLUSIONS

Sixteen percentage (27/168) of the hemangiomas in our study showed substantially lower attenuation than the portal vein in the PVP CT and this was more frequent in flash-fillers (52%, 14/27). The knowledge that fading does not preclude the diagnosis of hemangioma as well as of its high incidence in flash-fillers is important, as flash-filling hemangiomas with fading may cause a diagnostic challenge in patients suspected to have hypervascular malignancy.

Hypervascular hepatocellular carcinoma 1 cm or smaller in patients with chronic liver disease: characterization with gadoxetic acid-enhanced MRI that includes diffusion-weighted imaging

OBJECTIVE

The purpose of this study was to determine the finding most predictive for characterizing hypervascular hepatocellular carcinoma (HCC) measuring 1 cm or less at gadoxetic acid-enhanced MRI that includes diffusion-weighted images.

MATERIALS AND METHODS

In this retrospective study, between May 2008 and June 2009, 66 patients with 108 hypervascular HCCs 1 cm or smaller underwent gadoxetic acid-enhanced 3-T MRI that included diffusion-weighted images. The diagnosis of HCC was determined by surgical resection in 32 cases, percutaneous biopsy in three cases, or interval growth to larger than 1 cm on follow-up images in accordance with the American Association for the Study of Liver Diseases guidelines in 73 cases. MRI findings of HCC and 33 benign hypervascular lesions in a control group were analyzed by two radiologists in consensus. They based their assessments on the presence or absence of the following five findings: hyperintensity on T2-weighted images, hyperintensity on diffusion-weighted images with low b values, washout pattern, capsular enhancement, and hypointensity on gadoxetic acid-enhanced hepatobiliary phase images. The findings were compared by use of univariate and multivariate analyses.

RESULTS

No HCC with capsular enhancement was found. Fifty-seven HCCs (52.8%) had four findings, 36 (33.3%) had three, nine (8.3%) had two findings, and six (5.6%) had one finding. Univariate analysis showed significant differences between the HCC and control groups with respect to four findings (p < 0.0001). Multivariate analysis showed that hyperintensity on T2-weighted (p < 0.0001) and diffusion-weighted (p = 0.0081) images were statistically significant MRI findings for predicting HCC.

CONCLUSION

Hyperintensity on both T2- and diffusion-weighted images is helpful in the diagnosis of hypervascular HCC smaller than 1 cm in diameter.

Detection of pancreatic carcinoma and liver metastases with gadoxetic acid-enhanced MR imaging: comparison with contrast-enhanced multi-detector row CT

PURPOSE

To intraindividually compare gadoxetic acid-enhanced magnetic resonance (MR) imaging with contrast material-enhanced multi-detector row computed tomography (CT) in detection of pancreatic carcinoma and liver metastases.

MATERIALS AND METHODS

The ethics committee approved this retrospective study with waiver of informed consent. This study included 100 patients (53 men, 47 women; mean age, 67.8 years) consisting of 54 patients with pathologically confirmed pancreatic carcinoma (mean size, 33 mm) and 46 without a pancreatic lesion. Sixty-two liver metastases (mean size, 10 mm) in 15 patients with pancreatic carcinoma were diagnosed at pathologic examination or multimodality assessment. Three readers blinded to the final diagnosis interpreted all MR (precontrast T1- and T2-weighted and gadoxetic acid-enhanced dynamic and hepatocyte phase MR images) and tetraphasic dynamic contrast-enhanced CT images and graded the presence (or absence) of pancreatic carcinoma and liver metastasis on patient-by-patient and lesion-by-lesion bases. Receiver operating characteristic analysis, McNemar test, and Fisher test were performed to compare the diagnostic performance of CT and MR imaging.

RESULTS

No significant differences were observed between CT and MR images in depiction of pancreatic carcinoma. However, MR imaging had greater sensitivity in depicting liver metastasis than did CT for two of the three readers in the MR imaging-versus-CT analysis (85% vs 69%, P = .046) and for all three readers in the lesion-by-lesion analysis (92%-94% vs 74%-76%, P = .030-.044).

CONCLUSION

Gadoxetic acid-enhanced MR imaging was equivalent to dynamic contrast-enhanced CT in depicting pancreatic carcinoma and had better sensitivity for depicting liver metastases, suggesting the usefulness of gadoxetic acid-enhanced MR imaging for evaluation of patients with pancreatic carcinoma.

Volume perfusion-CT of the liver: insights and applications

The purpose of this article is to provide an up-to-date view on the spectrum of applications of volume perfusion-CT in the liver. Volume perfusion-CT yields important information on liver architecture and function by enabling quantification of dual liver parenchymal blood supply. Additional characterization of diffuse and focal liver diseases by illustration of distinct flow dynamics and permeability may become an important adjunct in the CT-evaluation of liver pathologies.

Hepatic incidentalomas

Recent advances in multidetector-row computed tomography, magnetic resonance imaging, and ultrasonography have led to the detection of incidental hepatic lesions in both the oncology and nononcology patient population that in the past remained undiscovered. These incidental hepatic lesions have created a management dilemma for both clinicians and radiologists. In this review, guidelines concerning the diagnosis and management of some of the more common hepatic incidentalomas are presented.

Is hepatotropic contrast enhanced MR a more effective method in differential diagnosis of hemangioma than multi-phase CT and unenhanced MR?

BACKGROUND

Cavernous hemangiomas are the most frequent neoplasms of the liver and in routine clinical practice they often need to be differentiated from malignant tumors and other benign focal lesions. The purpose of this study is to evaluate whether diagnostic accuracy of magnetic resonance imaging (MRI) of hepatic hemangiomas, showing atypical pattern on US, improves with the use of Gd-BOPTA in comparison with contrast-enhanced multi-phase computed tomography (CT).

METHODS

178 consecutive patients with ambiguous hepatic masses showing atypical hyperechoic pattern on grey-scale US, underwent unenhanced and contrast-enhanced multi-phase multi-detector CT and MR (1.5T) with the use of liver-specific contrast medium gadobenate dimeglumine (Gd-BOPTA). After intravenous contrast administration arterial (HAP), venous-portal (PVP), equilibrium phases (EP) both in CT and MR and additionally hepatobiliary phase (HBP) in MR were obtained. 398 lesions have been detected including 99 hemangiomas and 299 other lesions.

RESULTS

In non-enhanced MDCT examination detection of hemangiomas was characterized by sensitivity of 76%, specificity of 90%, PPV of 71%, NPV of 92% and accuracy of 86%.Non-enhanced MR examination showed sensitivity of 98%, specificity of 99%, PPV of 99%, NPV of 99% and accuracy of 99%.After intravenous administration of contrast medium in MR the mentioned above parameters did not increase significantly.

CONCLUSION

Gd-BOPTA-enhanced MR in comparison with unenhanced MRI does not improve diagnostic accuracy in discriminating hemangiomas that show non-specific appearance in ultrasound examination. Unenhanced MR as a method of choice should directly follow US in course of diagnostic algorithm in differentiation of hemangiomas from other liver tumors.

Optimising the scan delay for arterial phase imaging of the liver using the bolus tracking technique

Objective:

To optimize the delay time before the initiation of arterial phase scan in the detection of focal liver lesions in contrast enhanced 5 phase liver CT using the bolus tracking technique.

Patients and Methods:

Delay - the interval between threshold enhancement of 100 hounsfield unit (HU) in the abdominal aorta and commencement of the first arterial phase scan. Using a 16 slice CT scanner, a plain CT of the liver was done followed by an intravenous bolus of 120 ml nonionic iodinated contrast media (370 mg I/ml) at the rate of 4 mL/s. The second phase scan started immediately after the first phase scan. The portal venous and delay phases were obtained at a fixed delay of 60 s and 90 s from the beginning of contrast injection. Contrast enhancement index (CEI) and subjective visual conspicuity scores for each lesion were compared among the three groups.

Results:

84 lesions (11 hepatocellular carcinomas, 17 hemangiomas, 39 other hypervascular lesions and 45 cysts) were evaluated. CEI for hepatocellular carcinomas appears to be higher during the first arterial phase in the 6 seconds delay group. No significant difference in CEI and mean conspicuity scores among the three groups for hemangioma, other hypervascular lesions and cysts.

Conclusion:

The conspicuity of hepatocellular carcinomas appeared better during the early arterial phase using a bolus tracking technique with a scan delay of 6 seconds from the 100 HU threshold in the abdominal aorta.