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

Abstract

ObjectivesCompared 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.MethodsForty 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).ResultsMDCT 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).ConclusionsDue 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.

A novel methodological approach using superimposed Micro‐CT and STL images to analyze hard and soft tissue volume in immediate and delayed implants with different cervical designs

“…Araujo et al (), Benic et al (), Bissinger et al (), Bressan et al (), Chappuis et al (), Feldkamp et al (), Fickl et al (), Passoni et al (), Puisys and Linkevicius (), Thoma et al (), Tonetti et al ().…”

“…This technology, however, has certain limitations since it only provides information at the soft tissue level precluding the understanding of the soft and hard tissue interplay. In recent years, micro‐computed tomography (Micro‐CT) has been extensively tested and proven as a valid method for the assessment of bone volumes (Bissinger et al, ; de Barros, Novaes, Carvalho, & Almeida, ). Thus, we have hypothesized that by merging Micro‐CT technology with STL image analysis, we could obtain valid information on the relative interaction of the soft and hard tissues in the peri‐implant tissue volume.…”

Bone structure determined by HR-MDCT does not correlate with micro-CT of lumbar vertebral biopsies: a prospective cross-sectional human in vivo study

“…We used μCT as a reference method to determine the actual bone architecture. μCT is a highly precise and reliable procedure for the in vitro evaluation of three-dimensional trabecular bone structure and is considered the gold standard for assessing bone above the cellular level [ 28 , 30 , 31 ]. It has shown good sensitivity to monitor postmenopausal osteoporotic changes in animal studies [ 32 ] and a higher validity than DXA for the evaluation of mechanical bone properties in ex vivo studies [ 33 – 35 ].…”

“…As a consequence, the object, e.g., a bone trabecula, only constitutes a part of the whole voxel and the depicted density is the mean value from the object itself and the remaining tissues contained in the voxel. This effect has already been described as a cause for over- or underestimation of certain parameters in animal studies [ 28 ].…”

“…To our knowledge, no study has so far examined the validity of spinal MDCT to represent actual bone architecture. We hypothesized that high-resolution MDCT might be an adequate tool for the diagnostic evaluation of bone architecture and designed a prospective controlled study to evaluate MDCT measurements in correlation to μCT analysis of vertebral biopsies, which is considered the gold standard for assessing bone above the cellular level [28].…”