Accelerated 3D T ₂ mapping with dictionary-based matching for prostate imaging

TY - JOUR

T1 - Accelerated 3D T 2 mapping with dictionary-based matching for prostate imaging

AU - Roccia, Elisa

AU - Vidya Shankar, Rohini

AU - Neji, Radhouene

AU - Lima da Cruz, Gastao

AU - Munoz, Camila

AU - Botnar, Rene

AU - Goh, Vicky

AU - Prieto, Claudia

AU - Dregely, Isabel

N1 - © 2018 International Society for Magnetic Resonance in Medicine.

PY - 2019/3/1

Y1 - 2019/3/1

N2 - PURPOSE: To develop a fast and accurate method for 3D T2 mapping of prostate cancer using undersampled acquisition and dictionary-based fitting.METHODS: 3D high-resolution T2 -weighted images (0.9 × 0.9 × 3 mm3 ) were obtained with a multishot T2 -prepared balanced steady-state free precession (T2 -prep-bSSFP) acquisition sequence using a 3D variable density undersampled Cartesian trajectory. Each T2 -weighted image was reconstructed using total variation regularized sensitivity encoding. A flexible simulation framework based on extended phase graphs generated a dictionary of magnetization signals, which was customized to the proposed sequence. The dictionary was matched to the acquired T2 -weighted images to retrieve quantitative T2 values, which were then compared to gold-standard spin echo acquisition values using monoexponential fitting. The proposed approach was validated in simulations and a T1 /T2 phantom, and feasibility was tested in 8 healthy subjects.RESULTS: The simulation analysis showed that the proposed T2 mapping approach is robust to noise and typically observed T1 variations. T2 values obtained in the phantom with T2 prep-bSSFP and the acquisition-specific, dictionary-based matching were highly correlated with the gold-standard spin echo method (r = 0.99). Furthermore, no differences were observed with the accelerated acquisition compared to the fully sampled acquisition (r = 0.99). T2 values obtained in prostate peripheral zone, central gland, and muscle in healthy subjects (age, 26 ± 6 years) were 97 ± 14, 76 ± 7, and 36 ± 3 ms, respectively.CONCLUSION: 3D quantitative T2 mapping of the whole prostate can be achieved in 3 minutes.

AB - PURPOSE: To develop a fast and accurate method for 3D T2 mapping of prostate cancer using undersampled acquisition and dictionary-based fitting.METHODS: 3D high-resolution T2 -weighted images (0.9 × 0.9 × 3 mm3 ) were obtained with a multishot T2 -prepared balanced steady-state free precession (T2 -prep-bSSFP) acquisition sequence using a 3D variable density undersampled Cartesian trajectory. Each T2 -weighted image was reconstructed using total variation regularized sensitivity encoding. A flexible simulation framework based on extended phase graphs generated a dictionary of magnetization signals, which was customized to the proposed sequence. The dictionary was matched to the acquired T2 -weighted images to retrieve quantitative T2 values, which were then compared to gold-standard spin echo acquisition values using monoexponential fitting. The proposed approach was validated in simulations and a T1 /T2 phantom, and feasibility was tested in 8 healthy subjects.RESULTS: The simulation analysis showed that the proposed T2 mapping approach is robust to noise and typically observed T1 variations. T2 values obtained in the phantom with T2 prep-bSSFP and the acquisition-specific, dictionary-based matching were highly correlated with the gold-standard spin echo method (r = 0.99). Furthermore, no differences were observed with the accelerated acquisition compared to the fully sampled acquisition (r = 0.99). T2 values obtained in prostate peripheral zone, central gland, and muscle in healthy subjects (age, 26 ± 6 years) were 97 ± 14, 76 ± 7, and 36 ± 3 ms, respectively.CONCLUSION: 3D quantitative T2 mapping of the whole prostate can be achieved in 3 minutes.

KW - 3T MRI

KW - T mapping

KW - prostate cancer imaging

KW - quantitative MRI

UR - https://www.scopus.com/pages/publications/85055578142

U2 - 10.1002/mrm.27540

DO - 10.1002/mrm.27540

M3 - Article

C2 - 30368900

SN - 0740-3194

VL - 81

SP - 1795

EP - 1805

JO - Magnetic resonance in medicine

JF - Magnetic resonance in medicine

IS - 3

ER -