Alternative representation of data presented in Figure 2.

<p>In order to better appreciate the evolution of Enhancement (Median and 25% and 75% Percentiles) over time-points, (a) represents Lower and Upper SCB, (b) the Upper EPZ and Lower EPZ, (c) the Upper and Lower Peripheral Disc and Central disc.</p

Example of the segmentation of discs in Regions of Interest.

<p>The disc on the left present a smooth, defectless endplate: all the ROIs were studied in this case. The disc on the right present a clear Schmorl’s node: only the central disc values were considered. An operator manually places points (A, B, C) to delimitate the border between endplate and disc. Care was taken so that the line between A_1 and A_2 and the line between C_1 and C_2 draw a line perpendicular to the endplates. The mean value of such distances was used to approximate the height of the disc. Each disc was then automatically divided by the software into 5 layered ROIs, named cranial and caudal Endplate Zone (EPZ), cranial and caudal Peripheral Disc and Central Disc. The EPZ is the ROI closer to the vertebral bone, and its height is 1/5 of the disc height; the Peripheral Disc borders with the EPZ and its height is 1/5 of the disc height, and the Central Disc is defined as the region in between the upper and lower Peripheral disc ROIs. A ROI corresponding to the vertebral body close to the disc was also defined starting from the border point with a fixed, arbitrary thickness of 6 pixel = 4.98 mm (Subchondral Bone, SCB): a thin layer of 1 pixel height separate SCB and EPZ, as it normally represent the “grey” border between bone and disc.</p

Median CSF- adjusted T2-weighted Signal Intensity in Central and Peripheral disc in disc divided on Pfirrmann grading.

<p>Error bars indicates 25% and 75% percentiles. Horizontal bars indicate which pairs have significant different values.</p

The significant determinants of central disc enhancement: multivariate associations.

<p>The significant determinants of central disc enhancement: multivariate associations.</p

Scatter plots of the Enhancement versus parameters expected to have an influence on the transport of the contrast agent.

<p>(a) CSF-adj T2-weighted versus Enhancement for POST_6H, with the linear fitting line for all data (solid line, R = −0.219, p<0.001) and only Pfirrmann 1,2 and 3 discs (dashed line, R = −0.06, p = 0.45). (b) Subject's age versus Enhancement for POST_6H, with the linear fitting line for all data (solid line, R = −0.219, p = 0.001) and only Pfirrmann 1,2 and 3 discs (dashed line, R = −0.014, p = 0.86). (c) Disc height versus Enhancement for POST_6H, with the linear fitting line for all data (solid line, R = −0.512, p<0.001) and only Pfirrmann 1,2 and 3 discs (dashed line, R = −0.469, p<0.001).</p

Representation of Median and Percentiles (25% and 75%) post contrast enhancement in all ROIs in 107 disc, from the upper SCB on extreme left to the lower SCB on the extreme right, at all time points considered.

<p>Representation of Median and Percentiles (25% and 75%) post contrast enhancement in all ROIs in 107 disc, from the upper SCB on extreme left to the lower SCB on the extreme right, at all time points considered.</p

Post-contrast enhancement in Central Disc in disc divided on level of degeneration following Pfirrmann grading.

<p>* indicates that Pfirrmann 5 discs enhance statistically more that Pfirrmann 1, 2 and 3,+indicates that Pfirrmann 4 enhance more than Pfirrmann 1,2 and 3 discs, ‡ indicates that Pfirrmann 4 enhances more than Pfirrmann 1 and 2, † indicates than Pfirrmann 4 enhances more than Pfirrmann 2.</p

Characteristics of the subjects recruited and influence of risk factors of lumbar spine pathologies.

1<p>5 patients had missing information about intensity of physical demand at work, thus a total of 262 data were available. Physical job demand score used: 0 = sedentary; 1 = light; 2 = medium; 3 = heavy.</p>2<p>1 patient had missing information about leisure physical activity per week, thus a total of 266 data were available.</p>3<p>Orthopedic conditions included: osteoarthrosis, hip, knee and hand osteoarthritis, and osteoporosis.</p><p>Subgroup 1 = patients with disc herniation alone; Subgroup 2 = patients with discopathies and/or osteochondrosis associated with disc herniation; Subgroup 3 = patients with discopathies and/or osteochondrosis without herniation; Subgroup 4 = patients with stenosis and/or spondylolisthesis.</p><p>Only significant P≤0.05 were indicated.</p

Association of lumbar spine pathologies and <i>VDR</i> FokI alleles.

<p>Subgroup 1 = patients with disc herniation alone; Subgroup 2 = patients with discopathies and/or osteochondrosis associated with disc herniation; Subgroup 3 = patients with discopathies and/or osteochondrosis without herniation; Subgroup 4 = patients with stenosis and/or spondylolisthesis. Subgroup A, Subgroup 1 grouped with Subgroup 2 (i.e. all hernia cases with or without concomitant additional conditions); Subgroup B, Subgroup 2 grouped with Subgroup 3; Subgroup C, all discopathies cases with or without concomitant disc herniation; Subgroup D, all osteochondrosis cases with or without concomitant disc herniation.</p>1<p>Adjusted OR: multivariate analysis, OR adjusted for age, BMI, family history, smoke, physical job demand and exposure to vibrations.</p><p>Only significant P≤0.05 were indicated.</p

Patient’s clinical assessment and classification in subgroups.

<p>a) Subgroup 1, patients with disc herniation only. b) Subgroup 2, patients with discopathies and/or osteochondrosis associated with disc herniation. c) Subgroup 3, patients with discopathies and/or osteochondrosis, without disc herniation, d–f) Subgroup 4, patients with stenosis (d), spondylolisthesis (e) or both (f). White arrows indicate the characteristic pathological features of each subgroup.</p