Soon Ho Yoon1, Chanhee Lee2, Jinil Park2, Jin Mo Goo1,3, Jang-Yeon Park2. 1. 1 Department of Radiology, Seoul National University College of Medicine, Seoul National University Hospital , Seoul , South Korea. 2. 2 Department of Biomedical Engineering, Center for Neuroscience Imaging Research, Institute for Basic Science, Sungkyunkwan University , Suwon-si , South Korea. 3. 3 Institute of Radiation Medicine, Seoul National University Medical Research Center , Seoul , South Korea.
Abstract
OBJECTIVE: To preliminarily investigate a technical feasibility of a submillisecond echo time concurrent-dephasing-and-excitation (CODE) sequence for pulmonary MRI on clinical and preclinical MR scanners Methods: CODE imaging (echo time, 0.14 ~ 0.18 ms) was performed with American College of Radiology phantom at 3 T, 7 healthy volunteers at 1.5 and 3 T, 10 rabbits at 3 T, and 2 rodents at 9.4 T. Signal-to-noise ratio was compared in phantom. Image quality of human MRI was visually assessed on a 5-point scale for comparison between CODE and conventional lung MRI sequences. Visibility of bronchi, subcentimeter nodules, and MR air-bronchogram were assessed in animal studies. RESULTS: In phantom study, signal-to-noise ratio was higher with CODE than with original three-dimensional ultrashort-echo time sequence (106.71 ± 4.32 vs 91.66 ± 3.54; p < 0.001). Image quality of human MRI was better with CODE than with conventional MRI sequences (p ≤ 0.002). Bronchi remained traceable up to the fifth bronchial generation in CODE images in rabbits and rodents. 95.2% of metastatic nodules (diameter, 1.5 ± 0.4 mm) and 93.8% of MR air-bronchogram (diameter, 0.9 ± 0.2 mm) in rabbits. CONCLUSION: Submillisecond echo time pulmonary MRI was technically feasible by using CODE on various MR scanners. Advances in knowledge: CODE can be a practical alternative for lung MRI on both clinical and pre-clinical scanners, without challenges of free-induction-decay-based ultrashort-echo time sequences.
OBJECTIVE: To preliminarily investigate a technical feasibility of a submillisecond echo time concurrent-dephasing-and-excitation (CODE) sequence for pulmonary MRI on clinical and preclinical MR scanners Methods: CODE imaging (echo time, 0.14 ~ 0.18 ms) was performed with American College of Radiology phantom at 3 T, 7 healthy volunteers at 1.5 and 3 T, 10 rabbits at 3 T, and 2 rodents at 9.4 T. Signal-to-noise ratio was compared in phantom. Image quality of human MRI was visually assessed on a 5-point scale for comparison between CODE and conventional lung MRI sequences. Visibility of bronchi, subcentimeter nodules, and MR air-bronchogram were assessed in animal studies. RESULTS: In phantom study, signal-to-noise ratio was higher with CODE than with original three-dimensional ultrashort-echo time sequence (106.71 ± 4.32 vs 91.66 ± 3.54; p < 0.001). Image quality of human MRI was better with CODE than with conventional MRI sequences (p ≤ 0.002). Bronchi remained traceable up to the fifth bronchial generation in CODE images in rabbits and rodents. 95.2% of metastatic nodules (diameter, 1.5 ± 0.4 mm) and 93.8% of MR air-bronchogram (diameter, 0.9 ± 0.2 mm) in rabbits. CONCLUSION: Submillisecond echo time pulmonary MRI was technically feasible by using CODE on various MR scanners. Advances in knowledge: CODE can be a practical alternative for lung MRI on both clinical and pre-clinical scanners, without challenges of free-induction-decay-based ultrashort-echo time sequences.
Authors: Olaf Dietrich; José G Raya; Scott B Reeder; Maximilian F Reiser; Stefan O Schoenberg Journal: J Magn Reson Imaging Date: 2007-08 Impact factor: 4.813
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