Extended Data Fig. 2: Collapse signal generation mechanism.
From: Ultrasensitive ultrasound imaging of gene expression with signal unmixing
The imaging target for all panels is ARG E. coli Nissle at 103 cells/ml in suspension. All images are displayed in dB scale with the same colormap shown in the bottom right of panel (g) (min: 0 dB, max: 80 dB). All scalebars are 2 mm. (a) Distribution of BURST ray line peak intensities (that is maxima over columns of pixels) for PPP = 4.3 MPa. N = 650. (b) Distribution of BURST+ ray line peak intensities for PPP = 4.3 MPa. N = 650. (c) BURST pressure ramp images with PPP ranging from 3.7 MPa to 4.3 MPa. (d) BURST+ pressure ramp with the same pressures as in (c). (e) Peak image intensity vs PPP for BURST and BURST+. Error bars: SEM. N = 10 BURST acquisitions. (f) Image time series acquired with an ultrafast implementation of BURST+, with 1 frame/100 µsec, at 4.3 MPa. (g) Cycle ramp images with the number of transmit waveform cycles ranging from 0.5 cycles to 10.5 cycles and PPP held constant at 4.0 MPa. (h) Mean intensity of cycle ramp images vs. depth. Traces are averaged over 10 replicates. Error bars not shown for clarity. (i) Proposed mechanism to account for the presence of dim signals, but not bright signals, in BURST. (j) Proposed mechanism to account for the presence of both dim and bright sources in BURST+ and pulse sequences with more than one cycle. (k) BURST (top) and BURST+ (bottom) images at 4.3 MPa with arrows indicating the punctate signal whose RF data is plotted in the following panels. (l-m) Beamformed RF waveforms for the BURST (top) and BURST+ (bottom) ray lines in (k) indicated by the arrows. The waveforms are acquired from the pre-collapse, low-pressure frame (l), the first high-pressure frame (m), and the second high-pressure frame (n) of the BURST or BURST+ pulse sequence for arrival times corresponding to a depth range of 18 mm to 23 mm. (o) N = 464 RF waveforms corresponding to dim (20–60 dB) BURST signals aligned by peak envelope intensity. (p) N = 304 RF waveforms corresponding to bright (60–80 dB) BURST+ signals aligned by peak envelope intensity. (q) N = 308 RF waveforms corresponding to dim (20–60 dB) BURST+ signals aligned by peak envelope intensity. (r) Full width at half maximum (FWHM) for the envelopes of the RF waveforms shown in panels (o-q). N = 464 ray lines for BURST, N = 308 ray lines for dim (20–60 dB) BURST+, and N = 304 ray lines for bright (60–80 dB) BURST+. Error bars represent ± SEM.
