CT evaluation of Chamberlain's, McGregor's, and McRae's skull-base lines

Cronin, C.G.; Lohan, D.G.; Mhuircheartigh, J.N.; Meehan, C.P.; Murphy, J.; Roche, C.

doi:10.1016/j.crad.2008.03.012

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Volume 64, Issue 1 , Pages 64-69, January 2009

CT evaluation of Chamberlain's, McGregor's, and McRae's skull-base lines

Department of Radiology, University College Hospital, Galway, Ireland

Received 27 November 2007; received in revised form 10 January 2008; accepted 6 March 2008.

Aim

To evaluate the mean distance from the odontoid process of C2 to the standard skull-base lines (Chamberlain's, McGregor's, and McRae's lines) on computed tomography (CT) imaging. To compare these measurements to previously documented plain radiograph and magnetic resonance imaging (MRI) measurements.

Materials and methods

Reformatted midline sagittal CT images of 150 adults were retrospectively evaluated. The shortest perpendicular distance was measured from the Chamberlain's, McGregor's and McRae's baselines for each subject to the odontoid tip. Statistical analysis was performed to compare the CT data with the previously obtained MRI and plain film data.

Results

The mean position of the odontoid process was 1.4mm below Chamberlain's line (median 1.2mm, SD 2.4mm), 0.8mm (median 0.9mm, SD 3mm) below McGregor's line and 5mm (median 5mm, SD 1.8mm) below McRae's line. There is no significant difference between male and female results (p>0.05) or between these CT and previous MRI measurements (p>0.05).

Conclusion

These results provide the mean and range of normal distance from the odontoid process to the most frequently used skull-base lines on the current population on CT.