Adaptive Autoregressive Model for Reduction of Noise in SPECT

Table 3

Percentage contrast resolution values for the different methods.

Method	RelAct	10 Ø	20 Ø	40 Ø	60 Ø
A
AR-OSEM-AR	0	18.4	56.3	74.6	84.2
BW-FBP	0	28.7	67.2	83.1	91.6
OSEM-BW	0	24.9	59.5	75.7	85.6
AR-OSEM-AR	2	9.0	86.1	84.3	103.5
BW-FBP	2	16.7	75.5	86.6	97.2
OSEM-BW	2	9.9	65.3	76.9	98.3
AR-OSEM-AR	4	136.5	253.0	270.4	296.5
BW-FBP	4	84.9	229.2	259.2	289.1
OSEM-BW	4	70.2	204.1	247.1	300.0
B
AR-OSEM-AR	0	21.5	58.0	76.1	84.8
BW-FBP	0	20.4	61.6	83.2	91.8
OSEM-BW	0	32.9	61.9	78.0	86.6
AR-OSEM-AR	2	32.8	81.0	81.9	95.7
BW-FBP	2	35.1	80.2	87.4	102.7
OSEM-BW	2	29.7	75.4	78.8	98.3
AR-OSEM-AR	4	132.8	230.2	269.8	295.7
BW-FBP	4	94.6	236.9	270.3	316.2
OSEM-BW	4	85.6	224.6	255.1	308.5
C
AR-OSEM-AR	0	24.0	55.9	75.0	85.5
BW-FBP	0	32.9	68.7	83.0	93.0
OSEM-BW	0	31.2	60.7	76.8	87.8
AR-OSEM-AR	2	41.1	76.0	86.9	94.9
BW-FBP	2	38.8	82.4	93.9	103.6
OSEM-BW	2	34.3	83.1	85.5	100.6
AR-OSEM-AR	4	119.4	237.1	266.3	297.7
BW-FBP	4	112.7	248.5	274.5	318.2
OSEM-BW	4	108.1	260.5	261.0	316.9

A: low count level; B: intermediate count level; C: high count level; AR-OSEM-AR: autoregressive filtering before and after ordered subset expectation maximisation algorithm; BW-FBP: Butterworth prefiltering and filtered back projection; OSEM-BW: ordered subset expectation maximisation algorithm and Butterworth postfiltering; RelAct: activity relative to background activity of 1; Ø: diameter.