Temporal Scalability of Dynamic Volume Data Using Mesh Compensated Wavelet Lifting

TL;DR

This paper presents a mesh compensated wavelet lifting method for scalable, lossless representation of high-resolution dynamic medical volumes, enabling efficient down-scaling and high-quality reconstruction for teleradiology.

Contribution

It introduces an optimized mesh compensation approach within wavelet lifting to improve the quality of scalable representations of dynamic CT and MR volumes.

Findings

Improved lowpass sub-band quality by 0.63 and 0.43 dB on average.

Achieved high-quality scalable representation with minimal rate increase.

Effective modeling of tissue displacement in dynamic volumes.

Abstract

Due to their high resolution, dynamic medical 2D+t and 3D+t volumes from computed tomography (CT) and magnetic resonance tomography (MR) reach a size which makes them very unhandy for teleradiologic applications. A lossless scalable representation offers the advantage of a down-scaled version which can be used for orientation or previewing, while the remaining information for reconstructing the full resolution is transmitted on demand. The wavelet transform offers the desired scalability. A very high quality of the lowpass sub-band is crucial in order to use it as a down-scaled representation. We propose an approach based on compensated wavelet lifting for obtaining a scalable representation of dynamic CT and MR volumes with very high quality. The mesh compensation is feasible to model the displacement in dynamic volumes which is mainly given by expansion and contraction of tissue over time. To achieve this, we propose an optimized estimation of the mesh compensation parameters to optimally fit for dynamic volumes. Within the lifting structure, the inversion of the motion compensation is crucial in the update step. We propose to take this inversion directly into account during the estimation step and can improve the quality of the lowpass sub-band by 0.63 and 0.43 dB on average for our tested dynamic CT and MR volumes at the cost of an increase of the rate by 2.4% and 1.2% on average.