Corrigendum to 'cavitation Emissions Nucleated by Definity Infused Through an EkoSonic Catheter in a Flow Phantom' [ultrasound in Med & Biol. 47 (2021) 693-709].

The authors regret that errors were present in this published manuscript. In equation (1), a set of brackets were inadvertently omitted. The original equation written as:EBF[n,r→]=1ρc0fs2Sa|∑l=1128SlXl[n]e−i2πnΔf|r→l−r→c0||2−∑l=1128|SlXl[n]|2(1) should read:EBF[n,r→]=1ρc0fs2Sa{|∑l=1128SlXl[n]e−i2πnΔf|r→l−r→c0||2−∑l=1128|SlXl[n]|2}(1) The beamformed energy has units of mJ µV2 MPa−2. The custom MATLAB code used to produce the results of this paper had the following errors:1.The parameter, Sl, in the left term of Eq. 1 was omitted in the computation.2.Immediately after EBF[n,r→] was computed using Eq. 1, negative values were forced to zero. To take advantage of frequency compounding (Szabo, 2014Szabo TL. Diagnostic ultrasound imaging: Inside out. Elsevier, New York, NY2014: 399Google Scholar), this step should have been performed after Eq. 2 for passive cavitation images and after Eq. 8 for total cavitation energy calculations. The total cavitation energy also has units of mJ µV2 MPa−2.3.When determining the ultraharmonics that were 3 dB higher than the average energy in the surrounding inharmonic bands, the conversion from volts to dB was missing a factor of 2. These errors have been corrected. Though the overall results and discussion presented in this paper are not impacted, Table 1 and Figures 5 through 8 are rendered below to correct the quantitative energy values:Table 1Four-parameter logistic fitting parameters for the ultraharmonic and inharmonic acoustic emissions as a function of Definity concentrationx1x2x3x4Ultraharmonic (R2 = 0.98)−0.42 ± 0.59−3.22 ± 3.0−1.88 ± 2.026.92 ± 0.79Inharmonic (R2 = 0.97)0.44 ± 1.11−3.48 ± 4.631.30 ± 1.836.92 ± 1.23 Open table in a new tab Fig. 6(a) Ultraharmonic and inharmonic acoustic emissions within seven 15-ms pulses at a pulse repetition frequency of 10 Hz. The concentration of Definity infused through the catheter was 4.0×107 microbubbles/mL. Data are represented as the mean ± standard deviation (n = 7). Time points 0.6, 1.7 and 11.5 ms are marked with gray dashed lines. The 0-ms time point corresponds to the start of the ultrasound pulse. (b) Cross-sectional multiplex images of cavitation emissions obtained by passive cavitation imaging for processing windows starting at 0.6 ms (left column), 1.7 ms (middle column) and 11.5 ms (right column). B-Mode ultrasound in gray scale and passive cavitation image overlays: signal from the transducers (harmonics) in blue, stable cavitation (ultraharmonics) in green and inertial cavitation (inharmonics) in red. The color maps represent values in decibels relative to 1 mJ μV2/MPa2. The bottom row illustrates the merged inharmonic and ultraharmonic layers, highlighting the spatiotemporal dynamics of stable and inertial cavitation.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Fig. 7(a) Stable and (b) inertial cavitation activity measured throughout Definity infusions at 2.0 mL/min through the EkoSonic catheter. The concentration of Definity infused through the catheter was 4.0×107 microbubbles/mL. Cavitation activity measured in phosphate-buffered saline (PBS) only (noise) is plotted as a dashed black line. Data are expressed as the mean ± standard deviation (n = 3). (c) Passive cavitation images of the average stable (left) and inertial (right) energy acquired over the course of one 3-min infusion of Definity.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Fig. 8(a) Stable and inertial cavitation activity at a single axial image location in the flow phantom during a single 3-min infusion at 2.0 mL/min with a catheter pullback rate of 0.5 mm/s. The concentration of Definity infused through the catheter was 4.0×107 microbubbles/mL. Data time points were aligned in post-processing to set the first peak at 0 s to compensate for positioning variability between experimental runs (n = 3). (b) Composite passive cavitation images acquired at time points when the array was above the first (T1) and fourth (T4) pairs of transducers.View Large Image Figure ViewerDownload Hi-res image Download (PPT) The authors would like to apologize for any inconvenience caused. This work was funded by the U.S. National Institutes of Health through Grant R01 HL135092 to the University of Cincinnati, Boston Scientific and University of Texas Health Science Center Houston for collaborative development of the EkoSonic Endovascular System for ultrasound-mediated drug delivery. Cavitation Emissions Nucleated by Definity Infused through an EkoSonic Catheter in a Flow PhantomUltrasound in Medicine and BiologyVol. 47Issue 3PreviewThe EkoSonic endovascular system has been cleared by the U.S. Food and Drug Administration for the controlled and selective infusion of physician specified fluids, including thrombolytics, into the peripheral vasculature and the pulmonary arteries. The objective of this study was to explore whether this catheter technology could sustain cavitation nucleated by infused Definity, to support subsequent studies of ultrasound-mediated drug delivery to diseased arteries. The concentration and attenuation spectroscopy of Definity were assayed before and after infusion at 0.3, 2.0 and 4.0 mL/min through the EkoSonic catheter. Full-Text PDF