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Purpose: This study was undertaken to compare the imaging findings of focal nodular hyperplasia (FNH) in men and women, as seen on multidetector computed tomography (MDCT), magnetic resonance imaging (MRI) and contrast-enhanced ultrasound (CEUS). Materials and methods: Two radiologists reviewed 195 imaging studies (17 MDCT, 81 MRI and 97 CEUS examinations) pertaining to 111 FNHs (mean size 3 cm) in 91 patients (mean age 39 years). For each lesion, the readers assessed size, location, echogenicity, attenuation, or signal intensity in comparison with adjacent liver parenchyma on both unenhanced and postcontrast images. Results: Eighty-nine FNHs (mean size 3.1 cm) were observed in 73 women (mean age 37.9 years) and 22 FNHs (mean size 2.7 cm) in 18 men (mean age 41.2 years). No statistically significant differences were found between men and women in terms of age, FNH lesions per patient (1.22 and 1.21, respectively), size, baseline and enhancement pattern on MRI, CEUS and MDCT ( p < 0.05). A central scar in FNHs was depicted in 4/18 (22.2 %) men and 16/63 (25.4 %) women on MRI ( p < 0.05), and in 1/2 (50 %) men and 7/15 (46.7 %) women on MDCT ( p < 0.05), whereas a spoke-wheel pattern, central scar, and/or feeding vessel were seen in 5/17 (29.4 %) men and 22/80 (27.5 %) women on CEUS ( p < 0.05). Conclusions: Our results did not show any differences in imaging features, age of occurrence and size of FNH between men and women. [ABSTRACT FROM AUTHOR]

Purpose: This study was undertaken to compare response evaluation criteria in solid tumours (RECIST) 1.1 and modified RECIST (mRECIST) in patients with unresectable hepatocellular carcinoma (HCC) on sorafenib, and to describe HCC enhancement changes before and after sorafenib treatment. Methods and materials: Seventeen patients (12 men, 5 women; mean age 69 years; age range 58-79 years) were included. Tumour response was assessed according to RECIST and mRECIST. Two readers placed a region of interest (ROI) within each target lesion, on the portion showing enhancement during the arterial phase. The lesion attenuation values measured within the ROIs on computed tomography or the signal intensity measured on magnetic resonance imaging, during the unenhanced phase, hepatic arterial phase and venous phase were recorded. Changes in arterial and venous contrast enhancement before and after treatment were compared among the mRECIST groups using Mann-Whitney U test. Results: Agreement between mRECIST and RECIST was good (Cohen's k coefficient, 0.791). Patients with partial response had a greater decrease in arterial enhancement (−79.8 %) than did patients with stable disease (SD) (−24.8 %; p = 0.011) or progressive disease (PD) (−32.9 %; p = 0.034). No statistically significant difference in arterial enhancement variation was found among patients with SD and PD. No statistically significant difference in venous enhancement was found among the mRECIST groups. Conclusions: mRECIST showed a more favourable response compared to RECIST 1.1 in patients with unresectable HCC receiving sorafenib. [ABSTRACT FROM AUTHOR]

Purpose: To retrospectively investigate the prevalence, MR findings, natural history, and association with other hepatic lesions of focal nodular hyperplasia (FNH)-like lesions in a cohort of consecutive patients with cavernous transformation of the portal vein (CTPV).Materials and Methods: This retrospective IRB-approved study comprised 58 patients (32 men, 26 women; average age, 50 years) with CTPV who underwent liver MR imaging between 2000 and 2008. MR images were assessed by two radiologists in consensus for the presence of (a) FNH-like lesions and other liver lesions, and (b) other imaging findings. Patients were assigned to a stable or progressive clinical course based on lesion characteristics at follow-up.Results: Twelve of 58 patients (21%) had 38 FNH-like lesions (average size, 1.3 cm). Common findings of FNH-like lesions were isointensity on T2-weighted images (82%), intense and homogeneous enhancement during the arterial phase, and lack of washout during the hepatic venous and interstitial phases (100%). FNH-like lesions were found with other benign liver lesions (1 hemangioma, 1 adenoma) in two patients. Three (25%) patients with FNH-like lesions showed a progressive clinical course.Conclusion: FNH-like lesions are commonly detected in patients with CTPV. Most lesions demonstrate benign imaging findings and stable clinical course. [ABSTRACT FROM AUTHOR]

Abstract: One key step in seismic data processing flows is the computation of static corrections, which relocate shots and receivers at the same datum plane and remove near surface weathering effects. We applied a standard static correction and a wave equation datuming and compared the obtained results in two case studies: 1) a sparse ocean bottom seismometers dataset for deep crustal prospecting; 2) a high resolution land reflection dataset for hydrogeological investigation. In both cases, a detailed velocity field, obtained by tomographic inversion of the first breaks, was adopted to relocate shots and receivers to the datum plane. The results emphasize the importance of wave equation datuming to properly handle complex near surface conditions. In the first dataset, the deployed ocean bottom seismometers were relocated to the sea level (shot positions) and a standard processing sequence was subsequently applied to the output. In the second dataset, the application of wave equation datuming allowed us to remove the coherent noise, such as ground roll, and to improve the image quality with respect to the application of static correction. The comparison of the two approaches evidences that the main reflecting markers are better resolved when the wave equation datuming procedure is adopted. [Copyright &y& Elsevier]

Focal liver lesions are common in the general population. Radiology (imaging) plays a pivotal role for the diagnosis, staging, treatment planning, and follow-up of focal liver lesions. To maximize lesion detection and characterization, imaging needs to be performed with appropriate equipment by using protocols carefully designed on the basis of the underlying clinical context. In addition, the decision of an imaging modality cannot be based on the diagnostic accuracy of an imaging test solely but must also consider patient safety and cost-effectiveness. [Copyright &y& Elsevier]

Abstract: In this article, we present the CT and MR imaging characteristics of the cirrhotic liver. We describe the altered liver morphology in different forms of viral, alcoholic and autoimmune end-stage liver disease. We present the spectrum of imaging findings in portal hypertension, such as splenomegaly, ascites and varices. We describe the patchy and lacelike patterns of fibrosis, along with the focal confluent form. The process of hepatocarcinogenesis is detailed, from regenerative to dysplastic nodules to overt hepatocellular carcinoma. Different types of non-neoplastic focal liver lesions occurring in the cirrhotic liver are discussed, including arterially enhancing nodules, hemangiomas and peribiliary cysts. We show different conditions causing liver morphology changes that can mimic cirrhosis, such as congenital hepatic fibrosis, “pseudo-cirrhosis” due to breast metastases treated with chemotherapy, Budd-Chiari syndrome, sarcoidosis and cavernous transformation of the portal vein. [Copyright &y& Elsevier]

The purpose was to compare human brain tissue perfusion in diabetic patients and healthy subjects with second harmonic imaging ultrasound and SonoVue to test the hypothesis that brain tissue perfusion differences are present in these two groups of patients. In a prospective case-control study, second harmonic examinations performed in 20 patients with type II diabetes mellitus and in 20 matched control patients were compared. After administration of 2.5 ml of SonoVue, 60 time-triggered images were recorded. Time-intensity curves, including peak intensity and positive gradient normalized to the middle cerebral artery, were calculated to quantify ultrasound intensity in a region of interest. The Mann-Whitney U-test was used to reveal any differences between healthy and diabetic subjects. Mean peak intensity was 0.64+/-0.1 Au in healthy subjects and 0.53+/-0.09 Au in diabetic patients. Mean positive gradient was 0.04+/-0.007 Au/s in healthy subjects and 0.04+/-0.008 Au/s in diabetic patients. Peak intensity and positive gradient were significantly lower in diabetic patients than in healthy subjects (P<0.05). Ultrasound examination with second harmonic imaging and SonoVue administration is able to detect clinically silent, reduced cerebral perfusion in type II diabetic patients. Diabetic patients have reduced cerebral perfusion in comparison to healthy subjects. [ABSTRACT FROM AUTHOR]

Purpose: This prospective study was conducted to evaluate the biologic effects of microbubble destruction with pulse-inversion harmonic imaging on rabbit liver parenchyma. Methods: The livers of 6 albino rabbits were examined sonographically by a single investigator. Three rabbits underwent contrast-enhanced sonography, with scanning starting 5 seconds after injection by using pulse-inversion harmonic imaging with a mechanical index of 1.2. Four time-triggered images were recorded at a rate of 1 frame every 2 seconds. For comparison, 3 control rabbits had pulse-inversion harmonic imaging with a mechanical index of 1.2 only, without contrast medium. Immediately after sonography, the animals were killed and uninterrupted, thin serial sections of the liver from both groups were analyzed by energy-filtered transmission electron microscopy. Results: The hepatic parenchyma of rabbits exposed to contrast agents had ultrastructural damage: mitochondria with fragmented crests; interrupted rough endoplasmic reticulum; enlarged intercellular spaces; highly vacuolized cytoplasmic areas; dilated sinusoids, sometimes with an irregular and interrupted endothelial wall; fragmented hepatocyte microvilli in dilated spaces of Disse; fragmented or missing microvilli in bile canaliculi; vacuolated and lysosome-deprived hepatic cytoplasm around the bile canaliculi; markedly injured or fragmented endothelium in larger vessels; and damaged basal membrane. Control-group results indicated that exposure to ultrasound alone did not cause ultrastructural damage to hepatic cells. Conclusions: Simultaneous exposure to contrast administration and pulse-inversion harmonic imaging with a high mechanical index causes ultrastructural damage in the rabbit liver. [ABSTRACT FROM AUTHOR]

The article is a reply to a commentary on the role of diffusion-weighted imaging (DWI) in the diagnosis of hepatocellular carcinoma (HCC) and its implication in the Liver Imaging Reporting and Data System (LI-RADS). The authors agree that DWI should be incorporated into the standard liver protocol and should include at least one acquisition with a high b-value. However, they note that restricted diffusion, although associated with the diagnosis of liver malignancies, is considered an ancillary feature in the LI-RADS algorithm and cannot be used to diagnose HCC noninvasively in the absence of other major features. They also suggest that contrast-enhanced ultrasound (CEUS) can serve as an alternative technique to confirm the diagnosis of HCC in patients with contraindications to CT/MRI contrast agent administration. In conclusion, while DWI is essential for the detection and characterization of focal liver lesions, the noninvasive diagnosis of definitive HCC can only be reached through contrast-enhanced imaging. [Extracted from the article]

Rim arterial phase hyperenhancement is an imaging feature commonly encountered on contrast-enhanced CT and MRI in focal liver lesions. Rim arterial phase hyperenhancement is a subtype of arterial phase hyperenhancement mainly present at the periphery of lesions on the arterial phase. It is caused by a relative arterialization of the periphery compared with the center of the lesion and needs to be differentiated from other patterns of peripheral enhancement, including the peripheral discontinuous nodular enhancement and the corona enhancement. Rim arterial phase hyperenhancement may be a typical or an atypical imaging presentation of many benign and malignant focal liver lesions, challenging the radiologists during imaging interpretation. Benign focal liver lesions that may show rim arterial phase hyperenhancement may have a vascular, infectious, or inflammatory origin. Malignant focal liver lesions displaying rim arterial phase hyperenhancement may have a vascular, hepatocellular, biliary, lymphoid, or secondary origin. The differences in imaging characteristics on contrast-enhanced CT may be subtle, and a multiparametric approach on MRI may be helpful to narrow the list of differentials. This article aims to review the broad spectrum of focal liver lesions that may show rim arterial phase hyperenhancement, using an approach based on the benign and malignant nature of lesions and their histologic origin. Critical relevance statement: Rim arterial phase hyperenhancement may be an imaging feature encountered in benign and malignant focal liver lesions and the diagnostic algorithm approach provided in this educational review may guide toward the final diagnosis. Key Points: Several focal liver lesions may demonstrate rim arterial phase hyperenhancement. Rim arterial phase hyperenhancement may occur in vascular, inflammatory, and neoplastic lesions. Rim arterial phase hyperenhancement may challenge radiologists during image interpretation. [ABSTRACT FROM AUTHOR]