{'fraction_non_alphanumeric': 0.01950078003120125, 'fraction_numerical': 0.015600624024960999, 'mean_word_length': 5.5126903553299496, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Optimal Individual Inversion Time in Brain Arterial Spin Labeling Perfusion Magnetic Resonance Imaging: Correlation With Carotid Hemodynamics Measured With Cine Phase-Contrast Magnetic Resonance Imaging

Objective The quantification of cerebral blood flow using pulsed arterial spin labeling could be erroneous with a nonoptimal inversion time (TI). We suggest that the optimal individual TI is dependent on the hemodynamic values of the supra-aortic vessels. Methods Twenty-two healthy volunteers (mean age, 31.8 years) underwent 7 pulsed arterial spin labeling scans at 3 T with TI ranging from 1200 to 1800 milliseconds every 100 milliseconds. The quantitative hemodynamic values of carotids were computed using a cine phase-contrast sequence. Optimal TIs were determined using visual and quantitative criteria. A correlation was sought between each optimal individual TI criterion and the hemodynamic parameter values. Results The optimal group TI was 1700 milliseconds. The individual analysis showed a significant correlation between the optimal TI of white matter signal-to-noise ratio and stroke distance, and the optimal TI of contrast-to-noise ratio with mean velocity. Conclusions A correlation was found between optimal individual TIs and carotid hemodynamic parameters.