Results for mean, range, and upper limits of normal PVST thickness on MDCT^*

	Mean PVST Thickness (range) (mm)	Upper Limit of Normal PVST Thickness (mm)
C1	4.4 (1.5–11)	8.5
C2	3.7 (1.5–8.5)	6
C3	4.2 (2–9.5)	7
C4	7 (2.5–16)	N/C
C5	12.4 (5–20)	N/C
C6	13 (5.5–24)	18
C7	11.6 (2.5–21)	18

Note:—N/C indicates that upper limits of normal at C4 and C5 were not calculated due to the inconsistent position of the esophagus and larynx among the patient population: PVST, prevertebral soft tissue; MDCT, multidetector CT.

^*Upper limit of normal calculated as 2 SDs above the mean maximum value for 97.5% of the population.