Noninvasive optoacoustic imaging of the human brain validated with magnetic resonance angiography

Imaging modalities capable of visualizing the human brain have led to major advances in neuroscience. Functional magnetic resonance imaging has enabled a better understanding of brain function and connectivity abnormalities in brain diseases and has become a workhorse in neuroimaging. Nuclear imaging technologies such as positron emission tomography and single-photon emission computed tomography assisted with radio-labelled tracers have further enabled molecular diagnosis and monitoring of brain diseases. Limitations of these established technologies, such as the high cost or the use of ionizing radiation as well as accessibility, have fostered the development of new imaging approaches that can complement or enhance their performance. Optoacoustic tomography (OAT) provides unique capabilities to study cerebral function by mapping changes in several hemodynamic parameters within the brain. It further provides molecular imaging capabilities that can facilitate disease diagnosis and treatment monitoring. However, OAT imaging of the human brain is severely hampered by acoustic attenuation and aberrations of ultrasound waves propagating through the skull. Herein, we performed transcranial OAT imaging through the temporal bone of an adult healthy volunteer based on a previously reported spherical ultrasound array. We validated the OAT results by using head-to-head time-of-flight (TOF) magnetic resonance angiography (MRA) and T1-weighted structural MRI. The superior middle cerebral vein in the temporal cortex was identified in the OAT images matching the observed location in TOF-MRA. This basic demonstration anticipates the development of new hardware and reconstruction algorithms, ultimately enabling accurate OAT imaging of the human brain cortex.