DOI: 10.5061/dryad.sn02v6x9n
title: In vivo noninvasive systemic myography of acute systemic vasoactivity in female pregnant mice

description: Altered vasoactivity is a major characteristic of cardiovascular and
 oncological diseases, and many therapies are therefore targeted to the
 vasculature. Therapeutics which are selective for the diseased vasculature
 are ideal, but whole-body selectivity of a therapeutic is challenging to
 assess in practice. Vessel myography is used to determine the functional
 mechanisms and evaluate pharmacological responses of vascularly-targeted
 therapeutics. However, myography can only be performed on ex vivo sections
 of individual arteries. We have developed methods for implementation of
 spherical-view photoacoustic tomography for non-invasive and in vivo
 myography. Using photoacoustic tomography, we demonstrate the measurement
 of acute vascular reactivity in the systemic vasculature and the placenta
 of pregnant mice in response to two vasodilators. Photoacoustic tomography
 simultaneously captured the significant acute vasodilation of major
 arteries and detected the selective vasoactivity of the maternal-fetal
 vasculature. Photoacoustic tomography has the potential to provide
 invaluable preclinical information on vascular response that cannot be
 obtained by other established methods.
description: In this dataset, we acquired 3D
 photoacoustic tomography image volumes of pregnant CD-1 mice (Gestational
 day 16) to demonstrate in vivo vasodilation during pregnancy. The 3D
 volumes were acquired using the TriTom photoacoustic tomography system
 (Photosound Technologies Inc., Houston, TX) every 38 seconds with a 3
 cm<sup>3</sup> volume of the abdomen of the animals. Each
 volume captured the systemic and fetal vasculature and
 placentas.   We treated the animals with the
 vasodilators sildenafil (sildenafil citrate, PHR1807, Sigma-Aldrich) and
 the G protein-coupled receptor G-1 (100089335, Cayman Chemical, Inc.). A
 volume of 0.1 mL of either G-1 (100 µg/kg of body weight in 5% DMSO and
 PBS), sildenafil (1 mg/kg body weight in PBS), or control PBS was
 administered through the right jugular vein catheter, followed by a flush
 of 0.1 mL PBS, while imaging continuously. B-mode
 ultrasound imaging (Vevo 2100, FUJIFILM VisualSonics, Inc., Toronto) was
 used to validate the extent of vasodilation and response time, using a
 single artery and G-1. The cross-sectional change in diameter of the
 artery was monitored continuously before, during, and post-drug
 administration for 1 hour. The diameter of the artery was measured
 manually using the measurement tools in the VevoLab software.
 The 3D images from the photoacoustic tomography system were
 acquired before, during, and after drug administration at 808 nm, the
 isosbestic point of the optical absorption of hemoglobin and oxyhemoglobin
 for 30 minutes. The laser fluence at the surface of the mouse skin was
 calculated to be 0.27, 0.325, and 0.142 mJ/cm<sup>2</sup> for
 690, 808, and 890 nm wavelengths respectively. The photoacoustic images
 were reconstructed using a standard modified back-projection algorithm
 (TriTom reconstruction software V3.0.3). After reconstruction, additional
 processing steps were performed in Matlab V2021b. In this 3D volumetric
 image, we monitored the systemic arteries including the internal thoracic
 artery, iliac artery branching from the abdominal aorta as well as uterine
 artery. In addition, we monitored multiple placentas with their fetuses
 where spiral arteries feed the placenta and umbilical cord connecting the
 fetal side of the placenta to the fetus. To measure the
 diameter of the artery, we applied a Frangi vesselness filter to enhance
 the vascular signal in the 3D images. The 3D images were visualized in
 Amira V6.0.1 (Thermo Fisher Scientific, Waltham, MA). We manually
 segmented the 3D volume of the internal thoracic arteries, iliac artery,
 and superficial EPA arteries and measured the arterial diameter. To
 measure the photoacoustic signal intensity of the placenta, fetal
 vasculature, and uterine artery volumes, we manually segmented the 3D
 volumes from 3D images using MATLAB.
description: # In vivo noninvasive systemic myography of acute systemic vasoactivity in
 female pregnant mice
 [https://doi.org/10.5061/dryad.sn02v6x9n](https://doi.org/10.5061/dryad.sn02v6x9n) ## Description of the data and file structure The list of data names with the corresponding figures is provided in the Excel sheet “Data\_list\_all\_figures.xlsx" to navigate the dataset. All data provided are in MAT file format. The parameters of 3D photoacoustic volumes are organized into four structures. The details of the structures and the main parameters with units are given below: 1. SCAN: This structure contains the metadata of the input scan. * Frames: Number of scan frames. * FrameTime: Time in seconds indicating acquired scan frame time counting from the beginning of acquisition. * Positions: Azimuthal angle in radians measured from the center of rotation. * PositionsTime: Time in seconds recorded at each azimuthal Positions. * ExcitationWavelength, Laser energy, and temperature (water tank) do not correspond to our experiment. Users are advised to follow the main article for these parameters. 2. DEVICE: This structure contains the information of the instrument used to acquire input scan data. * ImageVolume: Maximum reconstructed imaging volume (x, y, z) in meters. * Laser: In the experiment, we used the Opotek Phocus Benchtop laser. 3. TRANSDUCER: This structure contains information on photoacoustic transducer arrays and calibration. * Central frequency: in Hz for each line of transducer. * Elements: Number of transducer elements (data channels). * ProbeDistance: Probe to probe distance in meters. * ElementPosition: Position of transducer element in 3D cartesian coordinates (meters). * ImpulseResponse and SensorMap datasets are not provided in the structure and are not required to interpret the data. 4. IMAGE: * SpeedOfSound: The speed of sound in mm/µs that is used to reconstruct the volume. * Voxel: The voxel size in meters of the volume. * Size: Volume size in meters arranged in a 2 × 3 matrix. Each column represents the range of distance from negative to positive direction for each axis (x, y, z). * Data: The image volume data of the 3D reconstruction is represented in 0 to 65535 color scale. * IntensityScale: The absolute intensity data in a 1 × 2 array. The first variable represents the lowest intensity value and the second one is the highest intensity value of the reconstruction. Users are advised to navigate to the “IMAGE” structure in the MAT file to access the 3D volume (named “Data”). The 3D volumes were reconstructed using software provided by the manufacturer. The image volumes in this dataset are scaled from 0 to 65535. We did not apply any image processing on this dataset. The B-mode ultrasound images for validation of vasodilation in response to vasodilator G-1 contain the cine loop and are in MAT file format. The ultrasound image data is in (x, y, frame) format and the image intensity is scaled from 0 to 255. ## Code/Software The code and software are available upon request.