Table 3.
MR QA Summary Statistics for the remaining five imaging tests. The ACR recommended specifications for the various test values are provided in the last column.
| Measure | N | Mean (95%CI) | Standard Deviation | Coefficient Variation | Median | Min | Max | ACR specs |
|---|---|---|---|---|---|---|---|---|
| Slice thickness accuracy | 261 | 5.07 (5.00, 5.13) | 0.52 | 10.34 | 5.05 | 3.83 | 7.97 | 5 ± 0.7 mm |
| Slice 1 position accuracy | 262 | 1.98 (1.69, 2.28) | 2.40 | 121.00 | 2.00 | -5.00 | 9.00 | < 5 mm |
| Slice 11 position accuracy | 263 | 1.69 (1.42, 1.95) | 2.17 | 128.81 | 1.60 | -6.00 | 8.00 | < 5 mm |
| T1 percent integral uniformity | 261 | 94.60 (94.22, 94.98) | 3.09 | 3.27 | 95.20 | 70.32 | 99.95 | > 87.5 % |
| T2 percent integral uniformity | 259 | 94.28 (93.94, 94.62) | 2.77 | 2.94 | 94.80 | 70.37 | 99.80 | > 87.5 % |
| T1 signal ghosting ratio | 260 | 0.0024 (0.0021, 0.0028) | 0.0030 | 125.39 | 0.0014 | -0.0018 | 0.0240 | < 0.025 |
| T2 signal ghosting ratio | 256 | 0.0054 (0.0046, 0.0063) | 0.0068 | 125.85 | 0.0036 | -0.0067 | 0.0500 | < 0.025 |
| T1 low contrast detectability | 263 | 36.62 (36.19, 37.05) | 3.53 | 9.65 | 37.00 | 13.00 | 40.00 | > 9 |
| T2 low contrast detectability | 260 | 33.68 (32.98, 34.38) | 5.75 | 17.08 | 35.00 | 1.00 | 40.00 | > 9 |