Registered 3D Tagged MRI and Ultrasound Myocardial Elastography: Quantitative Strain Comparison
Ultrasound myocardial elastography (UME) and tagged magnetic resonance imaging (tMRI) are two imaging modalities that were developed in the recent years to quantitatively estimate the myocardial deformations. Tagged MRI is currently considered as the gold standard for myocardial strain mapping in vivo. However, despite the low SNR nature of ultrasound signals, echocardiography enjoys the widespread availability in the clinic, as well as its low cost and high temporal resolution. Comparing the strain estimation performances of the two techniques has been of great interests to the community. In order to assess the cardiac deformation across different imaging modalities, in this chapter, we developed a semiautomatic intensity and gradient-based registration framework that rigidly registers the 3D tagged MRIs with the 2D ultrasound images. In addition, we introduced a series of Gabor filter bank-based tMRI image analysis techniques to remove tagging lines or grids, track tagging sheets, and estimate myocardial strain values in tMRI. Based on the two registered modalities, we conducted spatially and temporally more detailed quantitative strain comparison of the RF-based UME technique and tagged MRI. From the experimental results, we conclude that qualitatively the two modalities share similar overall trends. But error and variations in UME accumulate over time. Quantitatively tMRI is more robust and accurate than UME.
KeywordsGabor Filter Circumferential Strain Myocardial Deformation Gaussian Envelope Harmonic Peak
- 10.Manglik T, Axel L, Pai W, Kim D, Dugal P, Montillo A, Qian Z (2004) Use of bandpass gabor filters for enhancing blood-myocardium contrast and filling-in tags in tagged MR images. In: Proceedings of the international society for magnetic resonance in medicine, p 1793Google Scholar
- 13.Lai WM (1993) Introduction to continuum mechanics, 3rd edn. Woburn, MA, Butterworth-HeinemannGoogle Scholar
- 14.Kallel F, Ophir J (1997) A least-squares strain estimator for elastography. Ultrasound Imaging 19:195208Google Scholar
- 15.Qian Z, Metaxas D, Axel L (2006) Extraction and tracking of MRI tagging sheets using a 3D Gabor filter bank. In: Proceeding of the international conference of the engineering in medicine and biology societyGoogle Scholar
- 16.Qian Z, Montillo A, Metaxas D, Axel L (2003) Segmenting cardiac MRI tagging lines using Gabor filter banks. In: Proceeding of the international conference of the engineering in medicine and biology society, pp 630–633Google Scholar