MR-derived CT-like Images for the Assessment of Acute Vertebral Fractures and Osseous Degenerative Changes in the Thoracolumbar Spine

Introduction Patients with spine pathologies commonly undergo both computed tomography (CT) and magnetic resonance (MR) imaging. Our purpose was to evaluate whether MR-derived CT-like images can potentially substitute for conventional CT to assess acute vertebral fractures and osseous degenerative changes.

Material and Methods Acute vertebral fractures (n = 44) as well as degenerative changes in nonfractured levels (n = 52) were evaluated in 26 patients (64 ± 16 years; 17 women) on CT and 3-T MR imaging including a high-resolution three-dimensional T1-weighted gradient-echo sequence based on which intensity-inverted CT-like images were calculated. Two radiologists evaluated morphological findings separately on CT and MR-derived CT-like images. Agreement between the two modalities as well as inter- and intrareader reproducibility were assessed using weighted Cohen’s κ and intraclass correlation coefficients (ICCs).

Results Quantitative measurements showed an almost perfect to perfect agreement among both modalities, with ICCs between 0.91 (95% confidence interval [CI], 0.74–0.96) for intervertebral foramen anteroposterior diameter and 0.99 (95% CI, 0.98–1) for vertebral body and disk height. Ordinal scaled parameters such as Genant and AO fracture classifications (each, κ 1.0) and the extent of osteophytes (κ 1.0), diffuse sclerosis (κ 0.79), and facet joint degeneration (κ 0.96) showed a substantial to perfect agreement. Inter- and intrareader ICCs as well as κ were substantial to excellent (> 0.90), respectively. Average acquisition time for the sequence was 5.12 ± 0.17 minutes.

Conclusion Excellent agreement among the two modalities and a high inter- and intrareader reproducibility suggest that for the assessment of vertebral fractures and osseous degenerative changes, MR-derived CT-like images are on par with conventional CT. This finding could spare patients additional examinations and radiation doses.