Aplio

To characterize changes in bubble echogenicity over time under constant insonation and in a more clinically relevant setting, grayscale intensity changes generated by the SBNBs were measured in vitro using a linear transducer (Toshiba, Tochigi-Ken, Japan) and a clinical US scanner (Toshiba Aplio) at 6-MHz transmit frequency, 12 MHz receiving frequency and a peak negative pressure of 240 kPa (mechanical index, 0.1). This data were collected using nonlinear contrast mode imaging. Phantoms were custom designed from agarose mold (1% agarose, $99\%{\mathrm{H}}_2\mathrm{O}$ ). Each phantom had three narrow channels (see Fig. 3). Bubbles were imaged using US for 8 consecutive minutes. The phantom channels were aligned to the center of the transducer element placed atop such that the transducer was in an inverted orientation.
Activated bubble solution was prepared at constant dilution of stock solution (1 in 100). Six images were acquired for each sample. A ROI was selected within each channel region. The average US power of all non-zero elements in a selected ROI was tracked with respect to time for the duration of the 8 min excitation. This data was averaged for all six measurements and normalized to data from a noise region within the image.

Two to four weeks before terminal experiments, we assessed cardiac function by echocardiography as described previously [9 (link)]. Mice were maintained under ~2% isoflurane anesthesia (adjusted to keep heart rate between 400 and 500 bpm) while two-dimensional M-mode ultrasound images were obtained in the parasternal short axis view (Aplio; Toshiba America Medical Systems, Tusin, CA). We determined left ventricular internal diameter during diastole (LVIDd) and systole (LVIDs) using Image J software. Fractional shortening (%) was calculated as (LVIDd – LVIDs)/LVIDd × 100. All echocardiography measures were completed between 17:00 and 21:00 h.

The DUS was performed with the patient in a supine and the left or right lateral position, depending on which renal artery was assessed. Assessments were performed by 2 operators, using a high-resolution ultrasound machine (TOSHIBA APLIO with a convex probe). The following parameters were assessed: the systolic velocity in aorta, the peak-systolic and the end-diastolic velocity in the index renal artery, the renal-aortic-ratio, resistive index in the renal artery, the intra-renal resistive index and the pole-to-pole kidney length of the index and contralateral kidneys.

Ultrasound scans were performed within six hours of admission, at least three times in the first week after birth and then weekly till discharge to a level two hospital. These scans are referred to as early cUS. At TEA, within 24 hours following MRI, cUS was repeated. This scan is referred to as term cUS. Scanning was performed with a Toshiba Aplio (Toshiba Medical Systems, Zoetermeer, The Netherlands) or ATL-5000 ultrasound machine (Philips Medical Systems, Best, The Netherlands) with a transducer frequency of 5–8 MHz. Using the anterior fontanel as an acoustic window, standard views were taken in the coronal and sagittal planes. Comprehensive evaluation of the cerebellum through the mastoid and posterior fontanel was not performed at the time in all neonates. Hence, cerebellar cUS abnormalities could not be analyzed in this paper.