Rapid advances in imaging technologies have pushed novel spectroscopic modalities such as Fourier transform infrared spectroscopy (FTIR) and X-ray absorption spectroscopy (XAS) at the sulfur K-edge to the forefront of direct in situ investigation of brain biochemistry.
In addition, two distinct topologically resolved spectroscopic modalities, spectral and fluorescence lifetime imaging, were combined with wide-field two-photon excitation for improved specificity of detection of corroles and fluorescent microspheres.
These in situ studies demonstrate a number of essential phenomena including ignition of individual catalyst particles and their mutual influence, while combination of the spectroscopic and imaging modalities of the NMR technique can be useful for the characterization of the chemical conversion under reactive conditions.
Another interesting application of metabolic imaging is Na MR imaging, as show by Jansen et al. They applied this innovative spectroscopic imaging technique as a diagnostic modality for early detection of myocardial ischaemia and viability in a rat model [ 5].
In this tutorial paper, we discussed the utility of matrix factorization for performing linear unmixing of imaging and spectroscopic data commonly acquired via microscopy modalities.
Integrated PET/MRI with hyperpolarized 13C magnetic resonance spectroscopic imaging (13C-MRSI) offers simultaneous, dual-modality metabolic imaging.
There are also several other imaging modalities (perfusion and diffusion weighted MRI, proton MR spectroscopic imaging, PET-CT) which can play a more significant role, maybe more important than the volumetry of anatomic lesions [ 33, 36, 58- 60].
The limitation with these diagnostic modalities has led to an interest in the development of spectroscopic analytical techniques for the diagnosis of cancer.
However, since Doppler OCT and related methods [ 19, 20] can also visualize the vasculature with high spatial resolution (with some exceptions e.g. if blood flow is negligible), it may be the functional spectroscopic capability of PA imaging that provides the dominant raison d'etre for combining the two modalities.
We note that although FTIR spectroscopic imaging was performed in this study, XAS at the sulfur K-edge was not used in an imaging modality, but rather for in situ bulk measurement of the average sulfur speciation.
