Parse it in chunks: 功能 (gōngnéng, function) + 磁共振 (cí gòngzhèn, magnetic resonance) + 成像 (chéngxiàng, imaging) + 术 (shù, technique). Drop the 功能 prefix and you get plain MRI: 磁共振成像 (cí gòngzhèn chéngxiàng).
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Specialist medical/scientific term. In casual writing the English abbreviation fMRI is increasingly used directly; the full Chinese form appears in academic papers, textbooks, and formal news.
