Table 4. Quantitative Image Quality Parameters.
| Cervicothoracic Spine | Thoracolumbar Spine | |||||
| Short-Bore MR Imaging | Open MR Imaging | P Value | Short-Bore MR Imaging | Open MR Imaging | P Value | |
| Arithmetic mean (SD) | Arithmetic mean (SD) | |||||
| T2w sagittal | n = 18 | n = 21 | n = 30 | n = 34 | ||
| SNRa | 16.9 (3.4) | 9.23 (2.1) | <.0001 | 16.4 (3.7) | 11.7 (2.8) | <.0001 |
| CNRb | ||||||
| Cerebrospinal fluid – Spinal cord | 18.1 (11.6) | 9.3 (5.5) | .005 | 22.3 (13.2) | 14 (5.6) | .007 |
| Cerebrospinal fluid – Vertebral bone | 19.3 (10.3) | 8.2 (5.7) | <.0001 | 24 (12.9) | 11.7 (6.3) | <.0001 |
| Contour sharpnessc | ||||||
| Cerebrospinal fluid – Spinal cord | 0.8 (0.1) | 1.1 (0.2) | <.0001 | 0.9 (0.1) | 1.5 (0.4) | <.0001 |
| Cerebrospinal fluid – Vertebral bone | 0.8 (0.1) | 1.1 (0.2) | <.0001 | 0.8 (0.1) | 1.2 (0.4) | <.0001 |
| T1w sagittal | n = 18 | n = 22 | n = 30 | n = 34 | ||
| SNRa | 22.9 (5.6) | 14.4 (3.6) | <.0001 | 21.6 (4.4) | 16.2 (3.4) | <.0001 |
| CNRb | ||||||
| Cerebrospinal fluid – Spinal cord | 10.3 (11.5) | 8.9 (5.1) | .6 | 17.7 (14.8) | 9.4 (7) | .008 |
| Cerebrospinal fluid – Vertebral bone | 8.4 (6.1) | 5.7 (3.8) | .1 | 8.2 (8.1) | 3.9 (2.6) | .009 |
| Contour sharpnessc | ||||||
| Cerebrospinal fluid – Spinal cord | 1.1 (0.1) | 1.7 (0.4) | <.0001 | 1.2 (0.3) | 1.8 (0.4) | <.0001 |
| Cerebrospinal fluid – Vertebral bone | 1.1 (0.1) | 1.9 (0.5) | <.0001 | 1.1 (0.1) | 1.8 (0.4) | <.0001 |
| T2w axial d | n = 19 | n = 22 | n = 49 | n = 54 | ||
| SNRa | 23.1 (6.4) | 11.9 (2.7) | <.0001 | 13.2 (6.6) | 7.3 (2.6) | <.0001 |
| CNRb | ||||||
| Cerebrospinal fluid – Spinal cord | 11.9 (13.3) | 11.1 (8.6) | .8 | |||
| White matter – Gray matter of the spinal cord | 10.9 (12.7) | 7.2 (4.7) | .2 | |||
| Cerebrospinal fluid – Vertebral bone | 23.1 (14.2) | 17.2 (10.9) | .1 | 15.2 (27.8) | 8.9 (4.9) | .1 |
| Contour sharpnessc | ||||||
| Cerebrospinal fluid – Spinal cord | 0.7 (0.1) | 0.9 (0.2) | <.0001 | |||
| Cerebrospinal fluid – Vertebral bone | 0.8 (0.1) | 1.3 (0.4) | <.0001 | 0.6 (0.1) | 1(0.3) | <.0001 |
a Overall mean value of signal-to-noise ratios (SNR) for corticospinal fluid, spinal cord, vertebral bone, fat tissue, and muscle.
b Contrast-to-noise ratios (CNR) were calculated by substracting the respective SNR.
c Values are distances in mm (±SD) that are neeeded for the signal to increase from 25% to 75% of the grayscale pixel value profile obtained with imageJ.
d In axial MR imaging of the thoracolumbar spine, the spinal cord was normally not included and could thus not be assessed.