Combined diffuse optical tomography and photoacoustic tomography for enhanced functional imaging of small animals: a methodological study on phantoms

Abstract

Hybrid imaging methods combining diffuse optical tomography (DOT) and other anatomical or nonoptical functional modalities have been widely investigated to improve imaging performance degraded by the strong optical scattering of biological tissues, through constraining the reconstruction process by prior structures. However, these modalities with different contrast mechanisms may be ineffective in revealing early-staged lesions with high optical contrast but no morphological changes. Photoacoustic tomography (PAT) is particularly useful for visualizing light-absorbing structures embedded in soft tissues with high spatial resolution. Although it is still challenging for PAT to quantitatively disclose the absorption distribution, the modality does provide reliable and specific a priori information differentiating light-absorbing structures of soft tissues and might be more appropriate to guide DOT in lesion diagnosis, as compared with other anatomical or nonoptical functional modalities. In this study, a PAT-guided DOT approach is introduced with both soft- and hard-prior regularizations. The methodology is experimentally validated on small-animal-sized phantoms using a computed-tomography-analogous (CT-analogous) PAT/DOT dual-modality system, focusing on future whole-body applications. The results show that the proposed scheme is capable of effectively improving the quantitative accuracy and spatial resolution of DOT reconstruction.

Spectral correction for handheld optoacoustic imaging by means of near‐infrared optical tomography in reflection mode

“…This means that, if we were to assess SO 2 values in arteries, the estimation error could be reduced from >30% to <10%. This error could potentially be further reduced by exploiting the full capacity of the hybrid OA/US/NIROT modality functioning on the basis of a mutual feedback system, where OA and US images are used to provide NIROT reconstructions with a priori knowledge . Such mutual feedback could also be used to facilitate the interpretation of the quantitative data delivered in vivo by OA, NIROT and US.…”

Noninvasive hemoglobin sensing and imaging: optical tools for disease diagnosis

“…4(b) ]. 124 – 126 At more restricted depths, below 1 cm, spectroscopic optical coherence tomography (OCT) is also applicable, combining broadband illumination with spectrally-resolved interferometric detection. Although these methods have been widely explored in the clinical research setting, they are only just beginning to find routine application in the clinic for patient management.…”

Methodologies on the Enhanced Spatial Resolution of Non-Invasive Optical Brain Imaging: A Review

“…Their results revealed that spatial resolution significantly improved by using kernel methodology. Similarly, several other researchers are frequently using predesigned phantoms to validate their results, for example [252]- [255].…”