Focal Nodular Hyperplasia of the Liver: Contrast‐Enhanced Ultrasonographic Features With Sonazoid

Abstract

Contrast-enhanced US using Sonazoid for focal nodular hyperplasia showed typical vascular patterns of central artery vascularity, stellate vascularity, and centrifugal enhancement. Most cases were either hyperenhanced or isoenhanced on serial dynamic- and Kupffer-phase imaging. Based on these results, CEUS can provide useful information for noninvasive focal nodular hyperplasia diagnoses.

The AFSUMB Consensus Statements and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound using Sonazoid

“…With this technique, scanning is conducted at a low MI, using a pulse inversion mode or amplitude modulation mode that changes the amplitude or the phase of the emission phase and receives nonlinear signals during continuous real-time scanning. The level of low MI in this technique usually ranges from 0.2 to 0.3 [10,[22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. However, the range of MI can be reduced to 0.1 [3,[38][39][40][41] and can be expanded to 0.4 [3].…”

“…Typically, a higher MI level can be used for Sonazoid than for other second-generation UCAs (as low as 0.05) [10], thanks to the specific resistance of Sonazoid microbubbles to the acoustic pressure. The location of the beam focus is set at the posterior margin of the liver and the frame rate is around 10 and up to 15 per second [22,26,31,42].…”

“…Imaging acquisition during the vascular phase is principally similar to that of other second-generation UCAs, in that the vascular phase includes the arterial, portal venous, and late phases, when microbubbles are confined to the vascular space following IV UCA injection, with slow degradation over 5 minutes [10,26,[43][44][45]. For the arterial phase, the time window for imaging acquisition begins as early as 10-20 seconds [10,37,40,45], continues to 30-50 seconds for optimal timing [10,31,37,38,40,45], and is considered to last up to 1 minute after UCA injection [24,26,28,32,34,38,45]. Nonlinear signals during this phase reflect the arterial enhancement of an organ or a lesion, providing information on its arterial supply or vascularity.…”

“…Nonlinear signals during this phase reflect the arterial enhancement of an organ or a lesion, providing information on its arterial supply or vascularity. The portal venous phase starts from 30 to 50 seconds [10,40,42,45], continues to 80-90 seconds for optimal timing [26,31,37,38], and is considered to last until 2 minutes after UCA injection [10,[24][25][26]37,38,40,42,45]. The late vascular phase continues after the portal venous phase, and is defined to last until microbubbles disappear from the vascular space [10,31,38,40,45].…”

“…Following the late vascular phase, an additional and specific phase is available with Sonazoid CEUS, and this is referred to as the postvascular phase [2,4,49]. The postvascular phase follows the late vascular phase, and the corresponding imaging acquisition window is generally considered to begin 10 minutes after the contrast injection when microbubbles are sufficiently accumulated in the Kupffer cells by phagocytosis and are nearly removed from circulation; this phase persists for several hours [22,[24][25][26]28,29,[31][32][33][34][40][41][42]45,46,50]. Most malignant lesions become hypoechoic from the portal phase to the postvascular phase, whereas most benign hepatocyte-origin lesions are iso-or hyperechoic during these phases.…”