Article Figures & Data
Figures
- Fig 1.
Midline roll- and yaw-corrected sagittal fast spin-echo T2-weighted MR image (TR/TE, 3816/105eff;echo train length, 16; section thickness, 4 mm; matrix 512 × 256; field of view, 20 cm). The short solid line corresponds to the Talairach AC-PC basal reference; The long solid line is drawn parallel to the Talairach AC-PC reference, and the dashed line passes through the superior cortical surface of the hard palate. Note in this prototypical case the angle subtended by the Talairach AC-PC line and the hard palate is 12°. AC, anterior commissure; PC, posterior commissure; HP, hard palate.
- Fig 2.
Lateral CT scout view from a study patient illustrating the axial scan prescription (dotted lines) with the HP+12 protocol angled +12° from a line passing through the hard palate (solid line). The solid line indicating the orientation of the hard palate has been offset a few millimeters inferiorly to provide a clear view of the hard palate.
- Fig 3.
Consecutive CT and MR examinations from the same subject taken on different days by using the HP+12 CT protocol and a direct Talairach referenced MR imaging protocol (3). First row illustrates axial CT and MR image prescription methodologies. Note in this archetypal patient the angle subtended by the hard palate and the AC-PC line as depicted on the sagittal T2-weighted MR image is 12°, matching the CT prescription protocol. The second and third rows illustrate a representative axial section from these examinations through the orbits and posterior fossa with differing CT windows or MR sequencing. Axial CT and MR sections are 5 mm and 4 mm thick, respectively. Note the excellent intra- and intermodality axial scan concordance.
Tables
Protocol R Accuracy Precision Mean SD N Mean SD N A. Full Data Seta AX + 15 9.36° 7.38° 200 7.53° 5.11° 100 OML* 0.78 5.73°* 4.56° 100 6.67° 5.34° 50 HP + 12 0.82 5.98°* 5.73° 100 5.32°* 4.38° 50 B. Reduced Data Set (Excessive Head Extension Controlled)b AX + 15 7.18° 6.78° 147 7.34° 5.38° 66 OML* 0.69 4.87°* 3.99° 78 6.77° 5.97° 35 HP + 12 0.87† 3.27°*,† 2.87° 69 4.37°*,† 3.79° 31 Note.—R, Pearson’s correlation coefficient; SD, standard deviation.
a Results for the full data set.
b Results controlled for head extension requiring gantry tilt prescription greater than 22°.
* , Significant improvement (P < .05) versus AX + 15 protocol.
† Significant improvement (P < .05) versus OML* protocol.
