Contrast‐Enhanced Ultrasound Quantification Assessment of Focal Fatty Variations in Liver Parenchyma

Abstract

Objectives The purpose of this study was to quantify contrast‐enhanced ultrasound enhancement of focal fatty sparing (FFS) and focal fatty infiltration (FFI) and compare it with adjacent liver parenchyma. Methods This was a retrospective observational study yielding 42 cases in the last 4 years. Inclusion criteria were a focal liver lesion, adequate video availability, and an established diagnosis of FFS or FFI based on clinical or imaging follow‐up or a second modality. Contrast‐enhanced ultrasound examinations were performed with a standard low–mechanical index technique. Commercially available software calculated quantitative parameters for a focal liver lesion and a reference area of liver parenchyma, producing relative indices. Results In total, 42 patients were analyzed (19 male) with a median age of 18 (interquartile range, 42) years and a median lesion diameter of 30 (interquartile range, 16) mm. The cohort included 26 with FFS and 16 with FFI. Subjectively assessed, 27% of FFS and 25% of FFI were hypoenhancing in the arterial phase, and 73% of FFS and 75% of FFI were isoenhancing. In the venous and delayed phases, all lesions were isoenhancing. The peak enhancement (P = .001), wash‐in area under the curve (P < .01), wash‐in rate (P = .023), and wash‐in perfusion index (P = .001) were significantly lower in FFS compared with adjacent parenchyma but not the mean transit time. In the FFI subgroup, no significant difference was detected. Comparing relative parameters, only the wash‐in rate was significantly (P = .049) lower in FFS than FFI. The mean follow‐up was 2.8 years. Conclusions Focal fatty sparing shows significantly lower and slower enhancement than the liver parenchyma, whereas FFI enhances identically. Focal fatty sparing had a significantly slower enhancement than FFI.

Incidental Findings in Pediatric Patients: How to Manage Liver Incidentaloma in Pediatric Patients

“…Fatty infiltration (steatosis) was generally considered to be a diffuse process involving the entire liver. FFL are typically observed in adult patients and have been identified in about 50% at autopsy and with different frequency of up to one-third in imaging studies [ 11 , 12 , 14 , 53 , 65 , 158 , 159 , 160 , 161 , 162 , 163 ]. FFL can be divided into hyperechoic focal fatty infiltration (FFI) and hypoechoic focal fatty sparing (FFS).…”

“…CEUS examination is “the” useful problem solving tool for the characterization of a focal fatty abnormality since it is prompt and readily available, thus demonstrating the underlying pathophysiological mechanism with demonstration of feeding vessels and almost identical arterial phase enhancement when compared with the surrounding liver parenchyma and no washout in the portal venous and late phases [ 161 ]. CT and MR imaging is generally not indicated and should be reserved for high-risk patients with underlying malignant diseases, scientific questions, and aims to determine non-invasively the hepatic fat content [ 45 , 69 , 75 , 76 , 162 , 165 , 166 ].…”

Kontrastverstärkte Sonografie (CEUS) zur Diagnostik fokaler Leberläsionen

“…Das Kontrastverhalten fokaler Anders-verfettungen unterscheidet sich meistens nicht vom übrigen Parenchym [8]. In der arteriellen Phase kann in Einzelfällen jedoch sowohl eine vorzeitige als auch eine verzögerte Kontrastierung beobachtet werden [9,10]. Der fehlende Kontrastverlust in der Spätphase schließt eine maligne Genese aus.…”

Diagnosis and Follow‐up of Incidental Liver Lesions in Children

“…Focal fatty infiltration is echogenic on US (Supplemental Digital Content 6, http://links.lww.com/MPG/C648 ), has low attenuation on CT, and has drop in signal on out-of-phase sequences on MRI (80). CEUS shows similar vascularity as compared with the surrounding parenchyma (81). Focal fatty sparing appears on US as a hypoechoic focus (Supplemental Digital Content 7, http://links.lww.com/MPG/C649 ) in the setting of liver steatosis (79).…”