Phantom calibrations: Measurements: Distance & area/volume - At 1% low-contrast:– Distance accurate to 1/50th of a pixel & area/volume accurate to 1/10th of a pixel.
Field-examples:
(1)–(2) 77 year-old patient (7041077) was imaged with MR sequences (i) T2_W_FS+SENSE (SENSE MR breast coil) and (ii) T1_W_3D_FS+GD (Gadolinium contrast injection).
Five consecutive image-slices of each MR sequence across the central breast region (with tumor) were analyzed.
Figure 1 shows the original image of 1,1,2,75 with ROI (Region of Interest) placed over the tumor,
Figure 2 shows the 7xROI 'before' enhancement,
Figure 3,
the 7xROI image 'after' the enhancement,
Figure 4,
the enhanced image with edge profiles and Figure 5,
the additional outlining of the edge profiles.
Sharper edge-profiles after enhancement facilitate clearer diagnosis and accurate area/volume measurement of the breast tumor.
Table 1 lists the measured results of the ten analyzed images.
To avoid complications from non-zero spacing between the consecutive 2D slices,
average area (As) and average volume (Vs) of the five consecutive slices were measured.
The ratio of As(T1) over As(T2) (or Vs(T1)/Vs(T2)) gives the percentage difference of the two methods.
Table 1
77 year-old patient (ID=7041077)
by T2_W_FS+SENSE
Image Slice# As Vs
------------------------------------------------------------------------------------------------
1,1,1,37 1066.27±19.03 3198.75±57.00
1,1,1,38 1055.15±13.57 3165.43±40.64
1,1,1,39 1111.44±15.33 3334.26±46.04
1,1,1,40 1052.28±19.97 3156.49±59.99
1,1,1,41 1054.26±16.68 3162.78±50.06
…......................................................................................................................
Average As(T2)=1067.88±16.92 Average Vs(T2)=3203.542±50.75
by T1_W_3D_FS+GD
Image Slice# As Vs
-------------------------------------------------------------------------------------------------
1,1,2,75 1361.96±17.10 4085.85±51.25
1,1,2,76 1258.15±17.55 3774.46±52.57
1,1,2,77 1406.98±20.60 4220.95±61.95
1,1,2,78 1386.78±19.07 4160.31±57.15
1,1,2,79 1282.86±20.72 3848.62±62.18
…......................................................................................................................
Average As(T1)=1339.346±19.01 Average Vs(T1)=4018.038±57.02
The difference of the use of: T1_W_3D_FS+GD over the use of: T2_W_FS+SENSE = As(T1)/As(T2) (or Vs(T1)/Vs(T2)) = 1339.346/1067.88 (or 4018.038/3203.542) ==> 25.42%.
======================================================
(3)–(4) Similarly,
a 53 year-old patient (1772234) was imaged with the above-mentioned two MR sequences to obtain the results in Table 2.
Table 2
53 year-old patient (ID=1772234)
by T2_W_FS+SENSE
Image Slice# As Vs
---------------------------------------------------------------------------------------------
1,1,2,28 491.01±9.26 1472.97±28.01
1,1,2,29 690.72±8.80 2072.11±26.38
1,1,2,30 600.89±9.19 1802.66±27.59
1,1,2,31 600.78±7.14 1802.37±21.42
1,1,2,32 584.44±11.50 1753.35±34.62
…..................................................................................................................
Average As(T2)=593.568±9.18 Average Vs(T2)=1780.69±27.60
by T1_W_3D_FS+GD
ImageSlice# As Vs
----------------------------------------------------------------------------------------------
1,1,1,59 911.87±10.92 2735.63±32.73
1,1,1,60 952.67±12.35 2858.10±37.16
1,1,1,61 807.60±13.42 2422.86±40.33
1,1,1,62 920.94±10.96 2762.79±32.84
1,1,1,63 837.09±11.75 2511.26±35.20
…...................................................................................................................
Average As(T1)=886.03±11.88 Average Vs(T1)=2658.128±35.65
The difference of the use of: T1_W_3D_FS+GD over the use of: T2_W_FS+SENSE = As(T1)/As(T2) (or Vs(T1)/Vs(T2)) = 886.03/593.568 (or 2658.128/1780.69) ==> 49.27%.