title: On the "keyhole" technique.
authors.forename: X
authors.initials: X
authors.lastname: Hu
mesh_terms: D000465:Algorithms; D016477:Artifacts; D005583:Fourier Analysis; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*