Abstract
We propose a new optical method based on comparative holographic projection for visual comparison between two abnormal follow-up magnetic resonance (MR) exams of glioblastoma patients to effectively visualize and assess tumor progression. First, the brain tissue and tumor areas are segmented from the MR exams using the fast marching method (FMM). The FMM approach is implemented on a computed pixel weight matrix based on an automated selection of a set of initialized target points. Thereafter, the associated phase holograms are calculated for the segmented structures based on an adaptive iterative Fourier transform algorithm (AIFTA). Within this approach, a spatial multiplexing is applied to reduce the speckle noise. Furthermore, hologram modulation is performed to represent two different reconstruction schemes. In both schemes, all calculated holograms are superimposed into a single two-dimensional (2D) hologram which is then displayed on a reflective phase-only spatial light modulator (SLM) for optical reconstruction. The optical reconstruction of the first scheme displays a 3D map of the tumor allowing to visualize the volume of the tumor after treatment and at the progression. Whereas, the second scheme displays the follow-up exams in a side-by-side mode highlighting tumor areas, so the assessment of each case can be fast achieved. The proposed system can be used as a valuable tool for interpretation and assessment of the tumor progression with respect to the treatment method providing an improvement in diagnosis and treatment planning.
Highlights
Follow-up of malignant tumors progression after surgery is a critical and vital criterion to evaluate the current state of a patient with respect to a given treatment method such as radiotherapy and/or chemotherapy [1, 2]
In the literature [2, 4,5,6], the follow-up of tumor progression is realized by visual comparison between two or more magnetic resonance (MR) images or computed tomography (CT) scans captured at different time with or without highlighting the brain abnormalities
The root mean square error (RMSE) which calculates the difference between the input image and the output image obtained from the numerical reconstruction of the phase distribution after the convergence of iterative Fourier transform algorithm (IFTA) was calculated
Summary
Follow-up of malignant tumors progression after surgery is a critical and vital criterion to evaluate the current state of a patient with respect to a given treatment method such as radiotherapy and/or chemotherapy [1, 2]. For a single slice, the brain tissue and/or tumor area is compared after completing CRT and at the progression In such a case, the calculated holograms are only modified by linear phase ramps to avoid the overlapping at the reconstruction plane. Displaying such a phase hologram (φF) on the SLM and illuminating it with a plane wave generates (across the back focal plane of a lens) the reconstructed follow-up images arranged in a side-by-side mode and highlighting certain features, i.e. in our case, the tumor area compared with the brain tissue
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