Background-Suppressed MR Venography of the Brain Using Magnitude Data: A High-Pass Filtering Approach

Table 1

The standard deviation and mean intensity of the 3D BR-MRV datasets obtained with the inverted Hamming and Fermi filters (×10⁻⁵). The maximum intensity of the original 3D magnitude dataset prior to the filtering was normalized to 1.0.

Filter size	Inverted Hamming						Inverted Fermi
	𝜎𝑡	𝜎𝑎	𝜎	𝐼𝑚,𝑡	𝐼𝑚,𝑎	𝐼𝑚	𝜎𝑡	𝜎𝑎	𝜎	𝐼𝑚,𝑡	𝐼𝑚,𝑎	𝐼𝑚
12×9	247	68.5	260	147	1.6	24.2	237	68.6	225	30.8	−6.3	−13.4
16×12	240	68.5	241	98	−1.8	7.8	229	68.3	207	21.5	−6.6	−13.4
24×18	227	68.5	216	56	−4.4	—	210	68.4	182	9.2	−6.5	−11.6
32×24	216	68.2	198	37	−5.4	—	196	68.0	169	3.1	−6.5	−10.0
48×36	200	67.6	176	19	−6.2	—	181	66.9	153	−1.0	−6.4	−8.2
64×48	189	67.3	163	11	−6.2	—	171	64.7	141	−2.3	−6.7	−7.1

𝜎_𝑡: standard deviation of intensity in brain tissue; 𝜎_𝑎: standard deviation of intensity in air; 𝜎: standard deviation of intensity in the entire dataset; 𝐼_𝑚,𝑡: mean of intensity in brain tissue; 𝐼_𝑚,𝑎: mean of intensity in air; 𝐼_𝑚: mean of intensity in the entire dataset.