Real-time monitoring of inertial cavitation effects of microbubbles by using MRI: In vitro experiments
Journal
Magnetic Resonance in Medicine
Journal Volume
77
Journal Issue
1
Pages
102-111
Date Issued
2017
Author(s)
Peng H.-H.
Wu C.-H.
Kang S.-T.
Zhang J.-W.
Liu H.-L.
Wang C.-H.
Yeh C.-K.
HH Peng
HH Peng
CH Wu
CH Wu
ST Kang
ST Kang
JW Zhang
JW Zhang
HL Liu
HL Liu
WS Chen
WS Chen
CH Wang
CH Wang
CK Yeh
CK Yeh
Abstract
PURPOSE: To investigate the feasibility of half-Fourier acquisition single-shot turbo spin-echo (HASTE) for real-time monitoring of signal changes because of water flow induced by inertial cavitation (IC) during microbubbles (MBs)-present focused ultrasound (FUS) exposure. THEORY AND METHODS: Strong turbulence produced in MB solution at the onset of IC results in the difficulty to refocus signal echoes and thus the decrease in signal intensity (SI). Fundamental investigations were conducted using an agar phantom containing MB dilutions exposed to 1.85-MHz FUS. The effects of various experimental conditions including MB concentrations, imaging slice thicknesses, chamber diameters, acoustic pressures, duty cycles, and pulse repetition frequencies (PRFs) were discussed. RESULTS: Continuous 2.8 MPa FUS exposure resulted in SI changed from 11% to 55% when MBs concentrations increased from 0.025% to 0.1%. When slice thickness increased from 3 mm to 6 or 8 mm, smaller SI changes were observed (84%, 59%, and 46%). Images acquired with chamber diameter of 6 and 3 mm showed SI changes of 84% and 35%, respectively. In burst modes, higher duty cycles exhibited higher SI changes, and lower PRFs exhibited smaller and longer SI decrease. CONCLUSION: Under various conditions, substantial signal changes were observable, suggesting the feasibility of applying HASTE to real-time monitor IC effect under FUS exposure. Magn Reson Med 77:102-111, 2017. © 2015 Wiley Periodicals, Inc.
Publisher
John Wiley and Sons Inc.
Type
journal article