Figure showing the mapping of acquired data onto **k** space and the resulting image. (*A*) Plot showing real data acquired (from the dry bovine bone sample) in the first 17 windows for two different trajectories in **k** space. Starting at **k** = (0,0,0), both the yellow-circle and blue-square points take five steps forward along the positive *k*_{z} direction (*N*_{z} = 5). Next the yellow circles (blue squares) move seven steps forward (backward) along the positive *k*_{y} direction (*N*_{y} = 7). Finally, both the yellow circles and blue squares step forward along the positive *k*_{x} direction (*N*_{x} = 19), for a total of 32 points. (*B*) A 3D plot of these two trajectories in **k** space. See Movie S1 to see how this mapping takes place. (*C*) Three-dimensional octahedron of **k**-space points measured with our imaging scheme (plotting the magnitude of the complex points in the time domain). The imaging time was just under 47 h. (*D*) Isosurface rendering of the 3D image of ^{31}P in two dry bovine bone blocks separated by a 1.1-mm gap obtained by Fourier transformation of *C*. The spatial resolution is 0.428 × 0.428 × 0.353 mm^{3}. Note the thru-hole in the top block, which was drilled using a 0.343-mm-diameter drill bit. The sample dimensions are 4.9 × 2.6 × 1.4 mm^{3} (bottom bone) and 4.2 × 2.4 × 1.4 mm^{3} (top bone). The isosurface value was chosen to show the presence of the thru-hole and is 65% of the maximum signal value. See Movie S2 for a better view of this 3D isosurface. (*E*) A 2D slice of the 3D data (zero-filled by a factor of four) with thickness of 0.107 mm. The cutoff for the minimum of the color scale is the isosurface value used in *D* to clearly show the thru-hole in the top bone and two partial holes in the bottom bone, made by the same 0.343-mm-diameter drill bit.

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