Automated classification of cerebral arteries and veins in the neonate using ultrafast doppler spectrogram

<i>Objective.</i>Cerebral arterial and venous flow (A/V) classification is a key parameter for understanding dynamic changes in neonatal brain perfusion. Currently, transfontanellar ultrasound Doppler imaging is the reference clinical technique able to discriminate between A/V using vascular indices such as resistivity index (RI) or pulsatility index (PI). However, under conditions of slow arterial and venular flow, small signal fluctuations can lead to potential misclassifications of vessels. Recently, ultrafast ultrasound imaging has paved the way for better sensitivity and spatial resolution. Here, we show that A/V classification can be performed robustly using ultrafast Doppler spectrogram.<i>Approach.</i>The overall classification steps are as follows: for any pixel within a vessel, a normalized Doppler spectrogram (NDS) is computed that allows for normalized correlation analysis with ground-truth signals that were established semi-automatically based on anatomical/physiological references. Furthermore, A/V classification is performed by computing Pearson correlation coefficient between NDS in ground-truth domains and the individual pixel's NDS inside vessels and finding an optimal threshold.<i>Main Results.</i>When applied to human newborns (<i>n</i>= 40), the overall accuracy, sensitivity, and specificity were found to be 88.5% ± 6.7%, 88.5% ± 6.5%, and 87.0% ± 8.8% respectively. We also examined strategies to fully automate this process, leading to a moderate decrease of 1%-3% in the same metrics. Additionally, when compared to the main clinical metrics such as RI, and PI, the receiver operating characteristic curves exhibited higher areas under the curve; on average by +36% (<i>p</i>< 0.0001) in the full imaging sector, +35% (<i>p</i>= 0.0116) in the cortical regions, +53% (<i>p</i>< 0.0001) in the basal ganglia, +28% (<i>p</i>= 0.0051) in the cingulate gyrus, and +35% (<i>p</i>< 0.0001) in the remaining brain structures.<i>Significance:</i>Our findings suggest that the proposed NDS-based approach can distinguish between A/V when studying cerebral perfusion in neonates.