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Phantom: 32 cm GE sphere (used on pillows without table.)
SequenceSE
TR300
TE20
PlaneT
FOV53
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: Body-QD
Analysis of Test Image
Coil ID: 1562
Test Images
# of Channels 1
Mean148148
Max194193
Min118118
Background
0.18.0
NoiseSD4.904.58
Measured Data Calculated ResultsMeanSNR
21.421.2
MaxSNR
28.027.6
Normal-ized
9.29.1
Uni-formity
75.6%75.9%
NoiseType
NEMAAir
LabelN
A
Philips Site Intera 8
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Body Sense CoilMfg.: Philips
Mfg. Date: 4/1/2003
Model: 4522 131 5575
Revision:
SN: 3000097431
Phantom: Philips Body disk
SequenceSE
TR300
TE20
PlaneT
FOV53
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: Body Synergy
The first composite image used CLEAR hence a greater signal uniformity.
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
Coil ID: 1531
Channel 1 Channel 2
Composites
Mean447455510440
Max1,0271,0451,0931,120
# of Channels 4
Mean1,191738737
Max1,4051,1471,147
Min770383379
Background
0.40.24.1
NoiseSD
5.933.792.80
Measured Data Calculated ResultsMeanSNR
142.0137.7172.5
MaxSNR
167.6214.0268.4
Normal-ized
61.159.274.2
Uni-formity
70.8%50.1%49.7%
NoiseType
NEMANEMA
Air
Ch1234
4.294.923.763.66
NoiseSD
NoiseType
AirAirAirAir
MeanSNR
% ofMean
68.360.688.978.8
77%68%
100%89%
MaxSNR
% ofMax
156.9139.2190.5200.5
78%69%95%
100%
Channel 3
LabelNclr
NA
Channels
Channel 4
Philips Site Intera 9
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Breast CoilMfg.: Philips
Mfg. Date: 3/1/2004
Model: 4522 131 17226
Revision:
SN: 300033255
Phantom: 2 1 liter bottles with pad between them
SequenceSE
TR300
TE20
PlaneC
FOV30
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: Breast (linear)
Analysis of Test Image
Coil ID: 1538
Test Images
# of Channels 1
Mean1,2281,236
Max1,3241,331
Min1,0931,099
Background
-8.08.6
NoiseSD
6.234.75
Measured Data Calculated ResultsMeanSNR
139.4170.5
MaxSNR
150.3183.6
Normal-ized
187.1228.8
Uni-formity
90.4%90.5%
NoiseType
NEMAAir
LabelN
A
Philips Site Intera 10
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Head and NeckMfg.: Philips
Mfg. Date: 6/1/2002
Model: 4522 131 5271/86
Revision:
SN: 4892890/000623
Phantom: ACR Phantom in Head, 3 liter bottle in neck
SequenceSE
TR300
TE20
PlaneT
FOV40
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: Head/Neck HAP
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
Coil ID: 1529
Channel 1 Channel 2
Composites
Mean
1,067449495
Max
1,1301,0741,174
# of Channels 3
Mean999999
1,0181,018
Max1,1621,1641,1641,167
Min777774823823
Background
0.26.6-0.26.8
NoiseSD
4.834.805.004.67
Measured Data Calculated ResultsMeanSNR
146.3136.4144.0142.8
MaxSNR
170.1158.9164.6163.8
Normal-ized
110.4103.0108.7107.8
Uni-formity
80.1%79.9%82.8%82.7%
NoiseType
NEMAAir
NEMAAir
Ch
HAP
4.772.871.45
NoiseSD
NoiseType
AirAirAir
MeanSNR
% ofMean
146.6102.5223.7
0%66%46%
100%
MaxSNR
% ofMax
155.2245.2530.6
0%29%46%
100%
Channel 3
LabelNheadAheadNneckAneck
Channels
Channel 4
Philips Site Intera 11
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Head SenseMfg.: Invivo
Mfg. Date: 3/1/2003
Model: 4522 132 14003
Revision:
SN: 000108
Phantom: ACR Phantom
SequenceSE
TR300
TE20
PlaneT
FOV40
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: SENSE-Head Port #1
This is normally an 8 channel coil, not a 6. channels 2 and 5 are actually 2 coils combined each.The results from Ports #1 & 2 are virtually identical.The first composite image used CLEAR hence a greater signal uniformity.
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
Coil ID: 1528
Channel 1 Channel 2
Composites
Mean366403356405404346
Max1,0871,1081,0531,1771,1281,037
# of Channels 6
Mean1,437859859
Max1,5171,1391,140
Min1,304597597
Background
-0.1-0.13.5
NoiseSD
4.392.422.44
Measured Data Calculated ResultsMeanSNR
231.5251.0230.7
MaxSNR
244.4332.9306.2
Normal-ized
174.8189.5174.2
Uni-formity
92.4%68.8%68.7%
NoiseType
NEMANEMA
Air
Ch123456
3.022.183.123.282.263.08
NoiseSD
NoiseType
AirAirAirAirAirAir
MeanSNR
% ofMean
79.4121.174.880.9
117.173.6
66%100%62%67%97%61%
MaxSNR
% ofMax
235.9333.1221.2235.2327.1220.6
71%100%66%71%98%66%
Channel 3
Channel 4 Channel 5 Channel 6
LabelN CL
NA
Philips Site Intera 12
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Head SenseMfg.: Invivo
Mfg. Date: 3/1/2003
Model: 4522 132 14003
Revision:
SN: 000108
Phantom: ACR Phantom
SequenceSE
TR300
TE20
PlaneT
FOV40
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: SENSE-Head Port #2
This is normally an 8 channel coil, not a 6. channels 2 and 5 are actually 2 coils combined each.The results from Ports #1 & 2 are virtually identical.
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
Coil ID: 1528
Channel 1 Channel 2
Composites
Mean369401359404402347
Max1,0951,1051,0641,1751,1221,040
# of Channels 6
Mean1,434856856
Max1,5111,1261,126
Min1,300596595
Background
-0.5-0.33.4
NoiseSD
4.342.402.42
Measured Data Calculated ResultsMeanSNR
233.7252.2231.8
MaxSNR
246.2331.8304.9
Normal-ized
176.4190.4175.0
Uni-formity
92.5%69.2%69.1%
NoiseType
NEMANEMA
Air
Ch123456
3.032.243.103.172.193.07
NoiseSD
NoiseType
AirAirAirAirAirAir
MeanSNR
% ofMean
79.8117.375.983.5
120.374.1
66%98%63%69%
100%62%
MaxSNR
% ofMax
236.8323.3224.9242.9335.7222.0
71%96%67%72%
100%66%
Channel 3
Channel 4 Channel 5 Channel 6
LabelN CL
NA
Philips Site Intera 13
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Knee/Foot QuadratureMfg.: Med. Advances
Mfg. Date: 1/1/2004
Model: 4522 132 14021
Revision:
SN: 38378
Phantom: 3 liter bottle in Knee, wrist phantom in foot
SequenceSE
TR300
TE20
PlaneT
FOV40
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: Knee/Foot
Analysis of Test Image
Coil ID: 1526
Test Images
# of Channels 1
Mean1,094994
1,4021,403
Max1,4701,0201,4701,471
Min959957
1,3691,370
Background
-0.78.0-0.78.0
NoiseSD
5.084.444.684.44
Measured Data Calculated ResultsMeanSNR
152.3146.7211.9207.1
MaxSNR
204.6150.5222.1217.1
Normal-ized
115.0110.7159.9156.3
Uni-formity
79.0%96.8%96.4%96.4%
NoiseType
NEMAAir
NEMAAir
LabelN
A
N
A
Philips Site Intera 14
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Knee/Foot QuadratureMfg.: Med. Advances
Mfg. Date: 1/1/2004
Model: 4522 132 14021
Revision:
SN: 38378
Phantom: 3 liter bottle in Knee, wrist phantom in foot
SequenceSE
TR300
TE20
PlaneS
FOV40
Nx256
Ny256
NSA2
BW28.096
Thickness3
Gap-
Coil Mode: Knee/Foot NPW
No phase wrap is used to eliminate wrap around of ghost into phantom.
Analysis of Test Image
Coil ID: 1526
Test Images
# of Channels 1
Mean687687
1,2241,224
Max925925
1,3381,340
Min212213
1,2061,207
Background
-0.24.6-0.24.6
NoiseSD
3.042.662.932.68
Measured Data Calculated ResultsMeanSNR
159.8169.2295.4299.3
MaxSNR
215.2227.9323.0327.7
Normal-ized
85.390.3
157.7159.8
Uni-formity
37.3%37.4%94.8%94.8%
NoiseType
NEMAAir
NEMAAir
LabelN
A
N
A
Philips Site Intera 15
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Shoulder Array - LargeMfg.: MRI Devices
Mfg. Date: 10/1/2004
Model: 102271
Revision:
SN: U17964
Phantom: Breast coil phantom
SequenceSE
TR300
TE20
PlaneT
FOV36
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: SMC-MRI-D 2345 (Shoulder)
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
Coil ID: 1539
Channel 1 Channel 2
Mean542804638503
Max1,0351,002947925
# of Channels 4
Mean799799
Max1,1071,106
Min389389
Background
0.12.8
NoiseSD
2.101.93
Measured Data Calculated ResultsMeanSNR
269.1271.3
MaxSNR
372.8375.5
Normal-ized
250.8252.8
Uni-formity
52.0%52.0%
NoiseType
NEMAAir
Ch1234
2.304.792.291.96
NoiseSD
NoiseType
AirAirAirAir
MeanSNR
% ofMean
154.4110.0182.6168.2
85%60%
100%92%
MaxSNR
% ofMax
294.9137.1271.0309.3
95%44%88%
100%
Channel 3 Channel 4
LabelNA
Composites
Philips Site Intera 16
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Shoulder Array - LargeMfg.: MRI Devices
Mfg. Date: 10/1/2004
Model: 102271
Revision:
SN: U17964
Phantom: Breast coil phantom
SequenceSE
TR300
TE20
PlaneS
FOV36
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: SMC-MRI-D 2345 (Shoulder)
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
Coil ID: 1539
Channel 1 Channel 2
Mean388518823391
Max1,0941,2111,2931,174
# of Channels 4
Mean534534
Max1,1011,101
Min188187
Background
0.32.3
NoiseSD
1.891.67
Measured Data Calculated ResultsMeanSNR
199.8209.5
MaxSNR
412.0432.0
Normal-ized
186.2195.3
Uni-formity
29.2%29.0%
NoiseType
NEMAAir
Ch1234
2.273.514.861.98
NoiseSD
NoiseType
AirAirAirAir
MeanSNR
% ofMean
112.096.7
111.0129.4
87%75%86%
100%
MaxSNR
% ofMax
315.8226.1174.3388.6
81%58%45%
100%
Channel 3 Channel 4
LabelNA
Composites
Philips Site Intera 17
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Shoulder Array - SmallMfg.: MRI Devices
Mfg. Date: 10/1/2004
Model: 102270
Revision:
SN: U17999
Phantom: Breast coil phantom
SequenceSE
TR300
TE20
PlaneT
FOV36
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: SMC-MRI-D 2345 (Shoulder)
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
Coil ID: 1561
Channel 1 Channel 2
Mean560715595929
Max1,1001,019870
1,299
# of Channels 4
Mean669669
Max971970
Min292291
Background
0.52.0
NoiseSD
1.571.47
Measured Data Calculated ResultsMeanSNR
301.4298.2
MaxSNR
437.4432.4
Normal-ized
280.9277.9
Uni-formity
46.2%46.2%
NoiseType
NEMAAir
Ch1234
1.974.811.703.88
NoiseSD
NoiseType
AirAirAirAir
MeanSNR
% ofMean
186.397.4
229.4156.9
81%42%
100%68%
MaxSNR
% ofMax
365.9138.8335.4219.4
100%38%92%60%
Channel 3 Channel 4
LabelNA
Composites
Philips Site Intera 18
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Shoulder Array - SmallMfg.: MRI Devices
Mfg. Date: 10/1/2004
Model: 102270
Revision:
SN: U17999
Phantom: Breast coil phantom
SequenceSE
TR300
TE20
PlaneS
FOV36
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: SMC-MRI-D 2345 (Shoulder)
Channel #2 is a little lower than normal for this coil... but.. it could be related to phantom position. I don’t think it is significant enough of a difference to merit action at this time.
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
Coil ID: 1561
Channel 1 Channel 2
Mean347451
1,021251
Max930
1,0471,603849
# of Channels 4
Mean441441
Max851850
Min198198
Background
0.31.6
NoiseSD
1.321.20
Measured Data Calculated ResultsMeanSNR
236.3240.8
MaxSNR
455.9464.2
Normal-ized
220.2224.4
Uni-formity
37.8%37.8%
NoiseType
NEMAAir
Ch1234
1.732.834.761.39
NoiseSD
NoiseType
AirAirAirAir
MeanSNR
% ofMean
131.4104.4140.6118.3
94%74%
100%84%
MaxSNR
% ofMax
352.3242.4220.7400.3
88%61%55%
100%
Channel 3 Channel 4
LabelNA
Composites
Philips Site Intera 19
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Spine - SynergyMfg.: 131
Mfg. Date: 3/1/1998
Model: 4522 131 4927
Revision:
SN: 2606370/S
Phantom: Philips Body Disk
SequenceSE
TR300
TE20
PlaneS
FOV53
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: Spine Coil 1&2
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
Coil ID: 1525
Mean257288
Max824929
# of Channels 5
Mean423424
Max825824
Min133133
Background
-0.71.7
NoiseSD
2.001.35
Measured Data Calculated ResultsMeanSNR
149.6205.8
MaxSNR
291.7400.0
Normal-ized
64.388.5
Uni-formity
27.8%27.8%
NoiseType
NEMAAir
Ch12
1.171.41
NoiseSD
NoiseType
AirAir
MeanSNR
% ofMean
143.9133.9
100%93%
MaxSNR
% ofMax
461.5431.8
100%94%
LabelNA
Composites Channel 1 Channel 2
Philips Site Intera 20
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Spine - SynergyMfg.: 131
Mfg. Date: 3/1/1998
Model: 4522 131 4927
Revision:
SN: 2606370/S
Phantom: Philips Body Disk
SequenceSE
TR300
TE20
PlaneS
FOV53
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: Spine Coil 2&3
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
Coil ID: 1525
Mean312340
Max1,0071,131
# of Channels 5
Mean555556
Max1,0621,070
Min146145
Background
-1.42.3
NoiseSD
3.341.74
Measured Data Calculated ResultsMeanSNR
117.5209.4
MaxSNR
224.9403.0
Normal-ized
50.590.0
Uni-formity
24.2%23.9%
NoiseType
NEMAAir
Ch23
1.491.59
NoiseSD
NoiseType
AirAir
MeanSNR
% ofMean
137.2140.1
98%100%
MaxSNR
% ofMax
442.9466.1
95%100%
LabelNA
Composites Channel 1 Channel 2
Philips Site Intera 21
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Spine - SynergyMfg.: 131
Mfg. Date: 3/1/1998
Model: 4522 131 4927
Revision:
SN: 2606370/S
Phantom: Philips Body Disk
SequenceSE
TR300
TE20
PlaneS
FOV53
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: Spine Coil 4&5
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
Coil ID: 1525
Mean184351
Max561
1,078
# of Channels 5
Mean319318
Max563561
Min126125
Background
0.61.2
NoiseSD
1.010.99
Measured Data Calculated ResultsMeanSNR
223.4210.5
MaxSNR
394.2371.3
Normal-ized
96.090.5
Uni-formity
36.6%36.4%
NoiseType
NEMAAir
Ch45
0.961.50
NoiseSD
NoiseType
AirAir
MeanSNR
% ofMean
125.6153.3
82%100%
MaxSNR
% ofMax
382.9470.9
81%100%
LabelNA
Composites Channel 1 Channel 2
Philips Site Intera 22
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Surface - C-1Mfg.: Philips
Mfg. Date: 2/1/2004
Model: 9896 030 02032
Revision:
SN: 001756
Phantom: PIQT
SequenceSE
TR300
TE20
PlaneC
FOV45
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: C1 Ports 1 & 2
Analysis of Test Image
Coil ID: 1533
Test Images
# of Channels 1
Mean1,3181,3081,3201,307
Max1,6081,5941,6051,595
Min914905908898
Background
10.16.812.46.8
NoiseSD
5.493.84
10.233.86
Measured Data Calculated ResultsMeanSNR
169.8223.291.3
221.9
MaxSNR
207.1272.0111.0270.8
Normal-ized
101.3133.154.4
132.3
Uni-formity
72.5%72.4%72.3%72.0%
NoiseType
NEMAAir
NEMAAir
LabelN P1
A P1
N P2
A P2
Philips Site Intera 23
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Surface - C-3Mfg.: Philips
Mfg. Date: 2/1/2004
Model: 9896 030 05011
Revision:
SN: 001612
Phantom: PIQT
SequenceSE
TR300
TE20
PlaneC
FOV45
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: C3
Analysis of Test Image
Coil ID: 1530
Test Images
# of Channels 1
Mean1,004995
Max1,6041,587
Min465461
Background
8.46.1
NoiseSD
10.423.48
Measured Data Calculated ResultsMeanSNR
68.1187.4
MaxSNR
108.9298.8
Normal-ized
40.6111.8
Uni-formity
44.9%45.0%
NoiseType
NEMAAir
LabelN
A
Philips Site Intera 24
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Surface - C-4Mfg.: Philips
Mfg. Date: 11/1/2003
Model: 9896 030 05021
Revision:
SN: 000383
Phantom: PIQT
SequenceSE
TR300
TE20
PlaneT
FOV45
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: C4
Analysis of Test Image
Coil ID: 1532
Test Images
# of Channels 1
Mean845838
Max1,6061,597
Min343339
Background
6.76.0
NoiseSD
6.263.39
Measured Data Calculated ResultsMeanSNR
95.5162.0
MaxSNR
181.4308.7
Normal-ized
56.996.6
Uni-formity
35.2%35.0%
NoiseType
NEMAAir
LabelN
A
Philips Site Intera 25
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Surface - E-1Mfg.: Philips
Mfg. Date: 5/1/2001
Model: 4522 131 66952
Revision:
SN: 457040/00293
Phantom: 3 liter bottle
SequenceSE
TR300
TE20
PlaneT
FOV36
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: E1
Analysis of Test Image
Coil ID: 1534
Test Images
# of Channels 1
Mean874868
Max1,0561,051
Min475473
Background
5.67.9
NoiseSD
5.734.36
Measured Data Calculated ResultsMeanSNR
107.9130.5
MaxSNR
130.3158.0
Normal-ized
100.5121.6
Uni-formity
62.1%62.1%
NoiseType
NEMAAir
LabelN
A
Philips Site Intera 26
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Synergy Flex-MMfg.: Philips
Mfg. Date: 3/1/2004
Model: 4522 131 66562
Revision:
SN: 300035170
Phantom: 5 liter bottle
SequenceSE
TR300
TE20
PlaneT
FOV40
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: Synergy Flex M
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
Coil ID: 1535
Mean402464
Max892926
# of Channels 2
Mean832830
Max995989
Min618614
Background
1.94.3
NoiseSD
4.743.53
Measured Data Calculated ResultsMeanSNR
124.1154.1
MaxSNR
148.5183.6
Normal-ized
93.7116.3
Uni-formity
76.6%76.6%
NoiseType
NEMAAir
Ch12
2.653.14
NoiseSD
NoiseType
AirAir
MeanSNR
% ofMean
99.496.8
100%97%
MaxSNR
% ofMax
220.6193.3
100%88%
LabelNA
Composites Channel 1 Channel 2
Philips Site Intera 27
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Synergy Flex-MMfg.: Philips
Mfg. Date: 3/1/2004
Model: 4522 131 66562
Revision:
SN: 300035170
Phantom: 5 liter bottle
SequenceSE
TR300
TE20
PlaneS
FOV40
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: Synergy Flex M
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
Coil ID: 1535
Mean431315
Max1,089841
# of Channels 2
Mean625624
Max849846
Min313314
Background
0.93.8
NoiseSD
3.973.17
Measured Data Calculated ResultsMeanSNR
111.3129.0
MaxSNR
151.2174.9
Normal-ized
84.097.4
Uni-formity
53.9%54.1%
NoiseType
NEMAAir
Ch12
3.522.72
NoiseSD
NoiseType
AirAir
MeanSNR
% ofMean
80.275.9
100%95%
MaxSNR
% ofMax
202.7202.6
100%100%
LabelNA
Composites Channel 1 Channel 2
Philips Site Intera 28
Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Wrist Coil - High Res.Mfg.: MRI Devices
Mfg. Date: 8/1/2005
Model: 105003
Revision:
SN: U24216
Phantom: Wrist Phantom
SequenceSE
TR300
TE20
PlaneT
FOV14
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: Wrist
Channel 2 is dead, channel 4 is very sick.
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
Coil ID: 1541
Channel 1 Channel 2
Mean7124
348147
Max7876
400178
# of Channels 4
Mean1,2941,294
Max1,3981,397
Min1,1681,172
Background
-0.018.4
NoiseSD
8.9811.27
Measured Data Calculated ResultsMeanSNR
101.975.2
MaxSNR
110.181.2
Normal-ized
628.0463.7
Uni-formity
91.0%91.2%
NoiseType
NEMAAir
Ch1234
4.913.834.814.68
NoiseSD
NoiseType
AirAirAirAir
MeanSNR
% ofMean
95.00.747.420.6
100%1%50%22%
MaxSNR
% ofMax
105.01.054.524.9
100%1%52%24%
Channel 3 Channel 4
LabelNA
Composites
Philips Site Intera 29
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Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Wrist Coil - High Res.Mfg.: MRI Devices
Mfg. Date: 8/1/2005
Model: 105003
Revision:
SN: U24216
Phantom: Wrist Phantom
SequenceSE
TR300
TE20
PlaneC
FOV20
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: Wrist
Channel 2 is dead, channel 4 is very sick.
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
Coil ID: 1541
Channel 1 Channel 2
Mean7905
583153
Max1,497
101,518303
# of Channels 4
Mean923923
Max1,6011,602
Min126127
Background
0.111.2
NoiseSD
3.927.31
Measured Data Calculated ResultsMeanSNR
166.582.7
MaxSNR
288.8143.6
Normal-ized
502.8249.8
Uni-formity
14.6%14.7%
NoiseType
NEMAAir
Ch1234
4.753.354.224.56
NoiseSD
NoiseType
AirAirAirAir
MeanSNR
% ofMean
109.01.090.522.0
100%1%83%20%
MaxSNR
% ofMax
206.52.0
235.743.5
88%1%
100%18%
Channel 3 Channel 4
LabelNA
Composites
Philips Site Intera 30
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Test Date: 3/2/2008RF Coil Performance Evaluation
Coil: Wrist Coil - High Res.Mfg.: MRI Devices
Mfg. Date: 8/1/2005
Model: 105003
Revision:
SN: U24216
Phantom: Wrist Phantom
SequenceSE
TR300
TE20
PlaneS
FOV20
Nx256
Ny256
NSA1
BW28.096
Thickness3
Gap-
Coil Mode: Wrist
Channel 2 is dead, channel 4 is very sick.
Analysis of Composite Image
Measured Data Calculated ResultsAnalysis of Uncombined Images
IntroductionThe primary goal of RF coil testing is to establish some sort of base line for tracking coil performance overtime. The most common measure is the Signal to Noise Ratio or SNR. In addition, we can look at overallsignal uniformity, ghosting level (or better - lack of ghosting) and in the case of phased array coils we lookat the SNR of each and every channel and at symmetry between channels. Unfortunately, there is no singlebest method for measuring SNR. Below I explain the different methods used and the rationale for each.
SNROne needs to measure the signal in the phantom (either mean or peak or both) and then divide that by thebackground noise. Measuring the signal is fairly straightforward, the noise can be more problematic. Thesimplest method is to measure the standard deviation (SD) in the background ‘air’. However, MRI imagesare the magnitude of complex data. The noise in the underlying complex data is Gaussian but it follows aRician distribution when the magnitude is used. The true noise can be estimated by multiplying the mea-sured SD by 1.526.
During the reconstruction process, most manufacturers perform various additional operations on the images,This could include geometric distortion correction, low pass filtering of the k-space data resulting in lowsignal at the edge of the images, RF coil intensity correction (PURE, CLEAR, SCIC, etc), and other pro-cessing during the combination of phased array data and parallel imaging techniques. All of these methodsdistort the background noise making it impossible to obtain an accurate (and reproducible) estimate of theimage noise in the air region. The alternative is to use a method which I shall refer to as the NEMA(National Electrical Manufacturers Association) method. The signal in the phantom area is a sum of theproton signal and noise. Once the signal to noise ratio exceeds 5:1, the noise in the magnitude image iseffectively Gaussian. To eliminate the proton signal, you acquire an image twice and subtract them. Themeasured SD in the phantom region should now be the true SD times the square root of 2. When determin-ing the SNR using the NEMA method, calculate the mean signal of the average of the two source imagesthen divide by .7071 x the SD measured in the same area as the mean signal.
Unfortunately, this doesn’t always work. It is absolutely imperative that the RF channel scalings, both trans-mit and receive, be identical with both scans. Any ghosting in the system is not likely to repeat exactly forboth scans and will cause a much higher SD. Finally, the phantom needs to be resting in place prior to thescan long enough for motion of the fluid to have died down. Depending on the size and shape of the phan-tom, this could take any where from 5 to 20 minutes.
One of the most common causes of ghosting is vibration from the helium cold-head. The best way to elimi-nate this artifact is to turn off the cold head, which will increase helium consumption. Because this vibra-tion is periodic, the ghosting is usually of an N over 2 (N/2) nature. The affect inside the signal region ofthe phantom can be minimized by using a FOV that is twice the diameter of the phantom (measured in thePE direction.) If the noise is to be measured in the air, then be sure to NOT make measurements to eitherside of the phantom in the PE direction.
Scan parameters also significantly affect measured SNR. For most of the testing performed in this documentI used a simple Spin Echo with a TR of 300, a TE of 20 and a slice thickness of 3mm and a receiver BW of28.1 KHz (a 1 pixel fat/water chemical shift). The FOV was varied depending on the size of the coil and thephantom used. All of the parameters used for each test can be found on each page immediately below thecoil description.
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Report LayoutEach page of this report lists the data from a single test. The top third of the page describes the coil andphantom information, followed by the scan parameters used. The middle third contains the numbers mea-sured and calculated results. This section will contain one table if the coil being tested is a single channelcoil (i.e. quadrature or surface coils) and two tables if it is a multi-channel phased array coil. The entries inthe table will be described further below. The bottom section contains a few lines of comments (ifnecessary), a picture of the coil with the phantom as used for the testing and one or more of the images thatwere used for the measurements.
There is usually one image for each composite image measurement and one image for each separate channelmeasurement. Each image shows the ROI (red line) where the mean signal was measured and two smallerROIs (green lines) where the signal minimum and maximum was found. In the top left corner of each imageis the mean signal in the large ROI. The bottom left corner contains the large ROI’s area (in mm2). The topright corner contains two numbers a mean and a standard deviation. If the NEMA method was used, thenthe top right corner will list the mean and SD of the large ROI (labeled ROI M and ROIsd) applied to thesubtraction image. If the noise was measured in the background air the the numbers are labeled Air M andAirSD.
Data TablesThe meaning of most of the entries in the data table are should be self evident with a few exceptions. Thefirst column in each table is labeled “Label”. In the composite analysis, this field may be empty or containsome sort of abbreviation to identify some aspect of the testing. Some possibilities are the letter N forNEMA, A for Air, L for Left, R for Right, C for CLEAR, NoC for No CLEAR. In the Uncombined Imagetable, the label usually contains the channel number or similar descriptor. The column labeled “Noise Type”will be either Air or SubSig which stands for Subtracted Signal, i.e. the NEMA method. Both tables containa column for Mean SNR and Max SNR which are the Mean or Max signal divided by the SD of the noisescaled by either 1.526 (Air) or 0.7071 (NEMA).
Composite Image Table: The final two columns in this table are “Normalized” and “Uniformity”. It can berather difficult to compare the performance of different coils particularly if different scan parameters areused. (Of course, it’s even more difficult from one scanner to another.) I have standardized most of my test-ing to use a spin echo with a TR/TE of 300/20msec and a thickness of 3 mm. The FOV changes to depend-ing on the size of the phantom used although I try to use a FOV that is at least twice the diameter of thephantom as measured in the PE direction. For one reason or another, a change may be made in the scanparameters (either accidentally or intentionally such as turning on No Phase Wrap to eliminate aliasing, etc.).In order to make it easier to compare SNR values I calculate a “Normalized” SNR value. This value is theo-retically what the SNR would be if a FOV of 30cm, 256x256 matrix, 1 average, receiver BW of 15.6 KHzand slice thickness of 3mm had been used. Obviously, the final number is affected by the T1/T2 values ofthe phantoms used as well as details of the coil and magnet field strength but it can be useful in certain situa-tions.
The “Uniformity” value is defined by the ACR as 1 - (max-min)/(max+min). This is most important whenlooking at volume coils or for evaluating the effectiveness of surface coil intensity correction algorithms(such as PURE, CLEAR or SCIC).
Uncombined Image Table: This table has two columns labeled “% of Mean” and “% of Max”. When ana-lyzing multi-channel coils it is important to understand the relationship between the different channels, theinherent symmetry that usually exists between channels. In a 8 channel head or 4 channel torso phased arraycoil, all of the channels are usually have about the same SNR. These two columns list how the SNR (eitherMean or Max) of each channel compares to the SNR of the channel with the maximum value.