Table 1.
Patients characteristics.
Fig 1.
Possible artifacts on apparent diffusion coefficient maps.
(A) Sagittal ADC map and (B), corresponding T2-WI and (C) colored overlay showing distortion of the signal (arrowhead) caused by previously implanted metal interspinous device (arrow).
Fig 2.
Protrusion type of disk herniation.
(A) Sagittal ADC map and (B), corresponding T2-WI and (C) colored overlay bulging annulus fibrosus and contained nucleus pulposus of L5-S1 disk. (D)–axial T2-weighted image showing location of the disc herniation.
Fig 3.
Protrusion type of disk herniation.
(A) Parasagittal ADC map, corresponding T2-WI (B), colored overlay (C) and axial T2-WI (D) showing L3-4 disk bulging with a horizontal hyperintense line on a T2-WI and ADC map representing fissure in the annulus fibrosus. Also note hyperintense ADC signal from the posterior longitudinal ligament which represents enlarged venous plexus.
Fig 4.
Extrusion type of disk herniation.
(A) Parasagittal ADC map, (B) corresponding T2-WI, and (C) colored overlay showing L5/S1 disk with extrusion composed of hyperintense central part (extruded nucleus pulposus) and hypointense edges (ruptured annulus fibrosus).
Fig 5.
Sequester type of disk herniation.
(A) Parasagittal ADC map, (B) sagittal T2-WI, (C) overlay and (D) axial T2-WI showing caudally migrated T2 hyperintence disk fragment occupying paraforaminal zone ADC, apparent diffusion coefficient; T2-WI, T2-weighted image.
Fig 6.
Flow chart of patients available for nerve root ADC analysis.
Of the patients with monoradicular symptoms, majority had increased ADC values from the compromised nerve root comparing to the neighboring adjacent and contralateral nerve roots.
Fig 7.
(A) ADC maps, T2-WI and merged images of left (ipsilateral) and right (contralateral) parasaggital lumbar scans of 38 y.o. male patient with right sided L5-S1 disk herniation. Regions of interest (15 mm2) were selected over the ipsilateral (arrows) contralateral (arrowheads) S1 nerve roots. (B) Axial T2-WI showing disk herniation. (C) Comparison of ADC values from the affected, contralateral, adjacent ipsilateral (S1 or L5), and adjacent contralateral nerve roots. Data calculated from 19 patients with symptomatic disk herniations. *—p < .01. ADC, apparent diffusion coefficient; T2-WI, T2-weighted image.
Fig 8.
Modic type 1 changes in the setting of degenerative spondylolisthesis.
(A) T1-WI shows hypointense signal; (B) T2-WI shows hyperintense signal; (C) ADC map shows hyperintense signal; (D) overlay of ADC map over T2 image depicts anatomical location of the regions with increased diffusivity corresponding to the margin of Modic 1 changes. ADC, apparent diffusion coefficient; T2-WI, T2-weighted image.
Table 2.
Modic changes, associated ADC values and Pfirrmann grades.
Fig 9.
Modic type 2 changes of the vertebral bone marrow adjacent to a degenerated intervertebral disk.
(A) T1-WI and (B) T2-WI show hyperintense signal. (C) ADC map and (D) overlay of ADC map over T2-WI show decreased signal intensity over the degenerated disk and over the area of reactive bone marrow changes. ADC, apparent diffusion coefficient; T2-WI, T2-weighted image.
Fig 10.
Pfirrmann disk degeneration grades and ADC maps.
Appearance of various grades of disk degeneration on the ADC maps is shown on the left panel. Diagram on the right shows comparison of mean ADC values in different Pfirrmann grades (all disks included in analysis, n = 452). ADC, apparent diffusion coefficient; T2-WI, T2 weighted image.
Fig 11.
Comparison of ADC heterogeneity in various Pfirrmann degeneration grades of all intervertebral disks.
Diagram showing ADC heterogeneity in intervertebral disks of Pfirrmann grades 2 through 5. 452 disks included in analysis. Significant differences were observed among all grades. ADC, apparent diffusion coefficient.
Fig 12.
Comparison of ADC heterogeneity from herniated and non-herniated disks in various Pfirrmann grades.
Diagram of ADC heterogeneity of herniated and non-herniated intervertebral disks stratified by the Pfirrmann grades. Significant differences were observed in the Pfirrmann 3 and 4 groups. Totally 114/452 (25%) disks were included in the analysis as herniated (grade 3, n = 42; grade 4, n = 57 and grade 5, n = 15), 316/452 (70%) as non-herniated (grade 2, n = 114; grade 3, n = 150; grade 4, n = 48; grade 5, n = 4), and 22/452(5%) disks were excluded from the analysis due to spondylolisthesis or lumbar stenosis without herniation. ADC, apparent diffusion coefficient, LDH, lumbar disk herniation.
Fig 13.
Assessment of ADC values from herniated and non-herniated disks in various Pfirrmann degeneration grades.
Diagram of mean ADC values in herniated and non-herniated intervertebral disks stratified y the Pfirrmann grades. Significant differences were observed in the Pfirrmann grades 3 and 4. Totally 114/452 (25%) disks were included in the analysis as herniated (grade 3, n = 42; grade 4, n = 57 and grade 5, n = 15), 316/452 (70%) as non-herniated (grade 2, n = 114; grade 3, n = 150; grade 4, n = 48; grade 5, n = 4), and 22/452(5%) disks were excluded from the analysis due to spondylolisthesis or lumbar stenosis without herniation. ADC, apparent diffusion coefficient, LDH, lumbar disk herniation.
Table 3.
Correlation analysis (R Spearman coefficients).
Fig 14.
Intraoperative pictures of spinal nerve roots with various degree of inflammation.
(A) 28 y.o. male with right sided L4-5 disk herniation. Representative intraoperative image after removal of the herniation shows red inflamed L5 nerve root (arrow). Right L5 nerve root ADC value is 1199 ± 113 x10-6 mm2/s; (B) 52 y.o. male M. with left sided herniated disk at L5-S1 level. Intraoperative picture after removal of the herniation shows slightly edematous S1 nerve root (arrow). Left S1 nerve root ADC value is 1030 ± 192 x1-6 mm2/s. ADC, apparent diffusion coefficient; LDH, lumbar disk herniation.