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Micro-CT vs. Whole Body Multirow Detector CT for Analysing Bone Regeneration in an Animal Model

View Article: PubMed Central - PubMed

ABSTRACT

Objectives: Compared with multirow detector CT (MDCT), specimen (ex vivo) micro-CT (μCT) has a significantly higher (~ 30 x) spatial resolution and is considered the gold standard for assessing bone above the cellular level. However, it is expensive and time-consuming, and when applied in vivo, the radiation dose accumulates considerably. The aim of this study was to examine whether the lower resolution of the widely used MDCT is sufficient to qualitatively and quantitatively evaluate bone regeneration in rats.

Methods: Forty critical-size defects (5mm) were placed in the mandibular angle of rats and covered with coated bioactive titanium implants to promote bone healing. Five time points were selected (7, 14, 28, 56 and 112 days). μCT and MDCT were used to evaluate the defect region to determine the bone volume (BV), tissue mineral density (TMD) and bone mineral content (BMC).

Results: MDCT constantly achieved higher BV values than μCT (10.73±7.84 mm3 vs. 6.62±4.96 mm3, p<0.0001) and consistently lower TMD values (547.68±163.83 mm3 vs. 876.18±121.21 mm3, p<0.0001). No relevant difference was obtained for BMC (6.48±5.71 mm3 vs. 6.15±5.21 mm3, p = 0.40). BV and BMC showed very strong correlations between both methods, whereas TMD was only moderately correlated (r = 0.87, r = 0.90, r = 0.68, p < 0.0001).

Conclusions: Due to partial volume effects, MDCT overestimated BV and underestimated TMD but accurately determined BMC, even in small volumes, compared with μCT. Therefore, if bone quantity is a sufficient end point, a considerable number of animals and costs can be saved, and compared with in vivo μCT, the required dose of radiation can be reduced.

No MeSH data available.


Bland-Altman plot of the difference (y-axis) between the measurements obtained by the two methods against their mean value (x-axis).The red line displays the mean difference, representing the bias between the methods. The green lines indicate the limits of agreement (mean of the differences ± 1.96 x SD of the differences).
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pone.0166540.g005: Bland-Altman plot of the difference (y-axis) between the measurements obtained by the two methods against their mean value (x-axis).The red line displays the mean difference, representing the bias between the methods. The green lines indicate the limits of agreement (mean of the differences ± 1.96 x SD of the differences).

Mentions: The bias is shown in the Bland-Altman plot (Table 2, Fig 5) as the mean difference (red line, deviation from 0) between the measurements obtained by MDCT and μCT, which represents the systematic error. The limits of agreement (LOA, mean of the differences ± 1.96 x SD of the differences) are shown as green lines. The spread of the deviations from the mean of the differences is displayed by the values within the limits of agreement (BV: ± 8.43 mm3, TMD: ± 328.49 mg HA/cm3; BMC: ± 4.81 mg) (Table 2).


Micro-CT vs. Whole Body Multirow Detector CT for Analysing Bone Regeneration in an Animal Model
Bland-Altman plot of the difference (y-axis) between the measurements obtained by the two methods against their mean value (x-axis).The red line displays the mean difference, representing the bias between the methods. The green lines indicate the limits of agreement (mean of the differences ± 1.96 x SD of the differences).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5120815&req=5

pone.0166540.g005: Bland-Altman plot of the difference (y-axis) between the measurements obtained by the two methods against their mean value (x-axis).The red line displays the mean difference, representing the bias between the methods. The green lines indicate the limits of agreement (mean of the differences ± 1.96 x SD of the differences).
Mentions: The bias is shown in the Bland-Altman plot (Table 2, Fig 5) as the mean difference (red line, deviation from 0) between the measurements obtained by MDCT and μCT, which represents the systematic error. The limits of agreement (LOA, mean of the differences ± 1.96 x SD of the differences) are shown as green lines. The spread of the deviations from the mean of the differences is displayed by the values within the limits of agreement (BV: ± 8.43 mm3, TMD: ± 328.49 mg HA/cm3; BMC: ± 4.81 mg) (Table 2).

View Article: PubMed Central - PubMed

ABSTRACT

Objectives: Compared with multirow detector CT (MDCT), specimen (ex vivo) micro-CT (μCT) has a significantly higher (~ 30 x) spatial resolution and is considered the gold standard for assessing bone above the cellular level. However, it is expensive and time-consuming, and when applied in vivo, the radiation dose accumulates considerably. The aim of this study was to examine whether the lower resolution of the widely used MDCT is sufficient to qualitatively and quantitatively evaluate bone regeneration in rats.

Methods: Forty critical-size defects (5mm) were placed in the mandibular angle of rats and covered with coated bioactive titanium implants to promote bone healing. Five time points were selected (7, 14, 28, 56 and 112 days). μCT and MDCT were used to evaluate the defect region to determine the bone volume (BV), tissue mineral density (TMD) and bone mineral content (BMC).

Results: MDCT constantly achieved higher BV values than μCT (10.73±7.84 mm3 vs. 6.62±4.96 mm3, p<0.0001) and consistently lower TMD values (547.68±163.83 mm3 vs. 876.18±121.21 mm3, p<0.0001). No relevant difference was obtained for BMC (6.48±5.71 mm3 vs. 6.15±5.21 mm3, p = 0.40). BV and BMC showed very strong correlations between both methods, whereas TMD was only moderately correlated (r = 0.87, r = 0.90, r = 0.68, p < 0.0001).

Conclusions: Due to partial volume effects, MDCT overestimated BV and underestimated TMD but accurately determined BMC, even in small volumes, compared with μCT. Therefore, if bone quantity is a sufficient end point, a considerable number of animals and costs can be saved, and compared with in vivo μCT, the required dose of radiation can be reduced.

No MeSH data available.