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Segmental quantitative MR imaging analysis of diurnal variation of water content in the lumbar intervertebral discs.

Zhu T, Ai T, Zhang W, Li T, Li X - Korean J Radiol (2015)

Bottom Line: T2 values significantly decreased from morning to evening, in the NP (anterior NP = -13.9 ms; central NP = -17.0 ms; posterior NP = -13.3 ms; all p < 0.001).Meanwhile T2 values significantly increased in the anterior AF (+2.9 ms; p = 0.025) and the posterior AF (+5.9 ms; p < 0.001).Segmental quantitative T2 MRI provides valuable insights into physiological aspects of normal discs.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.

ABSTRACT

Objective: To investigate the changes in water content in the lumbar intervertebral discs by quantitative T2 MR imaging in the morning after bed rest and evening after a diurnal load.

Materials and methods: Twenty healthy volunteers were separately examined in the morning after bed rest and in the evening after finishing daily work. T2-mapping images were obtained and analyzed. An equally-sized rectangular region of interest (ROI) was manually placed in both, the anterior and the posterior annulus fibrosus (AF), in the outermost 20% of the disc. Three ROIs were placed in the space defined as the nucleus pulposus (NP). Repeated-measures analysis of variance and paired 2-tailed t tests were used for statistical analysis, with p < 0.05 as significantly different.

Results: T2 values significantly decreased from morning to evening, in the NP (anterior NP = -13.9 ms; central NP = -17.0 ms; posterior NP = -13.3 ms; all p < 0.001). Meanwhile T2 values significantly increased in the anterior AF (+2.9 ms; p = 0.025) and the posterior AF (+5.9 ms; p < 0.001). T2 values in the posterior AF showed the largest degree of variation among the 5 ROIs, but there was no statistical significance (p = 0.414). Discs with initially low T2 values in the center NP showed a smaller degree of variation in the anterior NP and in the central NP, than in discs with initially high T2 values in the center NP (10.0% vs. 16.1%, p = 0.037; 6.4% vs. 16.1%, p = 0.006, respectively).

Conclusion: Segmental quantitative T2 MRI provides valuable insights into physiological aspects of normal discs.

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Related in: MedlinePlus

Colored T2 maps of lumbar intervertebral discs in morning (A) and evening (B) show evident change of T2 values in central parts of lumbar vertebral discs from morning to evening.
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Figure 3: Colored T2 maps of lumbar intervertebral discs in morning (A) and evening (B) show evident change of T2 values in central parts of lumbar vertebral discs from morning to evening.

Mentions: Five equally-sized rectangular regions of interest (ROIs) were placed manually from the anterior AF (ROI1) to the posterior AF (ROI5) in each IVD, on the middle slice of the sagittal T2-mapping image matched with conventional T2-weighted sagittal MR image (Fig. 2). Each ROI was 20% of the midline disc diameter. The outermost 20% of each disc was defined as AF tissue (anterior and posterior AF corresponded to ROI1 and ROI5); the area between the anterior and posterior AF was defined as NP; the anterior NP, the central NP and posterior NP tissues corresponded to ROI2 to ROI4 (11). The mean number of pixels for each ROI was approximately 50. Exemplary color-encoded T2 maps of the lumbar spine imaged in the morning and in the evening, respectively, were shown in Figure 3. Based on the 2 images obtained, the percentage of T2 value change was calculated as the difference of T2 values between evening and morning, divided by the T2 values in the morning. The degree of T2 variation in the IVDs over the day was calculated using the following formula: the degree of T2 variation (relative changes percent) = ([T2 value in the evening] - [T2 value in the morning]) / (T2 value in the morning) × 100%. Comparison of the changes in magnitude between multiple ROIs, were from the absolute values and presented as mean ± standard deviation.


Segmental quantitative MR imaging analysis of diurnal variation of water content in the lumbar intervertebral discs.

Zhu T, Ai T, Zhang W, Li T, Li X - Korean J Radiol (2015)

Colored T2 maps of lumbar intervertebral discs in morning (A) and evening (B) show evident change of T2 values in central parts of lumbar vertebral discs from morning to evening.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4296262&req=5

Figure 3: Colored T2 maps of lumbar intervertebral discs in morning (A) and evening (B) show evident change of T2 values in central parts of lumbar vertebral discs from morning to evening.
Mentions: Five equally-sized rectangular regions of interest (ROIs) were placed manually from the anterior AF (ROI1) to the posterior AF (ROI5) in each IVD, on the middle slice of the sagittal T2-mapping image matched with conventional T2-weighted sagittal MR image (Fig. 2). Each ROI was 20% of the midline disc diameter. The outermost 20% of each disc was defined as AF tissue (anterior and posterior AF corresponded to ROI1 and ROI5); the area between the anterior and posterior AF was defined as NP; the anterior NP, the central NP and posterior NP tissues corresponded to ROI2 to ROI4 (11). The mean number of pixels for each ROI was approximately 50. Exemplary color-encoded T2 maps of the lumbar spine imaged in the morning and in the evening, respectively, were shown in Figure 3. Based on the 2 images obtained, the percentage of T2 value change was calculated as the difference of T2 values between evening and morning, divided by the T2 values in the morning. The degree of T2 variation in the IVDs over the day was calculated using the following formula: the degree of T2 variation (relative changes percent) = ([T2 value in the evening] - [T2 value in the morning]) / (T2 value in the morning) × 100%. Comparison of the changes in magnitude between multiple ROIs, were from the absolute values and presented as mean ± standard deviation.

Bottom Line: T2 values significantly decreased from morning to evening, in the NP (anterior NP = -13.9 ms; central NP = -17.0 ms; posterior NP = -13.3 ms; all p < 0.001).Meanwhile T2 values significantly increased in the anterior AF (+2.9 ms; p = 0.025) and the posterior AF (+5.9 ms; p < 0.001).Segmental quantitative T2 MRI provides valuable insights into physiological aspects of normal discs.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.

ABSTRACT

Objective: To investigate the changes in water content in the lumbar intervertebral discs by quantitative T2 MR imaging in the morning after bed rest and evening after a diurnal load.

Materials and methods: Twenty healthy volunteers were separately examined in the morning after bed rest and in the evening after finishing daily work. T2-mapping images were obtained and analyzed. An equally-sized rectangular region of interest (ROI) was manually placed in both, the anterior and the posterior annulus fibrosus (AF), in the outermost 20% of the disc. Three ROIs were placed in the space defined as the nucleus pulposus (NP). Repeated-measures analysis of variance and paired 2-tailed t tests were used for statistical analysis, with p < 0.05 as significantly different.

Results: T2 values significantly decreased from morning to evening, in the NP (anterior NP = -13.9 ms; central NP = -17.0 ms; posterior NP = -13.3 ms; all p < 0.001). Meanwhile T2 values significantly increased in the anterior AF (+2.9 ms; p = 0.025) and the posterior AF (+5.9 ms; p < 0.001). T2 values in the posterior AF showed the largest degree of variation among the 5 ROIs, but there was no statistical significance (p = 0.414). Discs with initially low T2 values in the center NP showed a smaller degree of variation in the anterior NP and in the central NP, than in discs with initially high T2 values in the center NP (10.0% vs. 16.1%, p = 0.037; 6.4% vs. 16.1%, p = 0.006, respectively).

Conclusion: Segmental quantitative T2 MRI provides valuable insights into physiological aspects of normal discs.

Show MeSH
Related in: MedlinePlus