Comparison of computed tomographic and magnetic resonance imaging in fracture healing after spinal injury

Abstract

Study design: Single-centre, prospective (comparative cohort) clinical study, with ethical approval and patient consent. Objective: Confirmation of vertebral fracture union can pose significant challenges for clinicians in the management of spinal cord injury and in the decisions around patient mobilization. Bony union is usually assessed with computed tomography (CT). This study hypothesizes that magnetic resonance imaging (MRI) can identify vertebral bone union. Setting: A major spinal injuries unit in the United Kingdom. Method: Patients underwent CT and MRI at 12 weeks post-injury, if conservatively managed, or 12 weeks post-fixation. With CT as the gold standard, the MRI scans were reviewed blind to the CT result and indicators for fracture healing were compared. Results: A total of 35 patients with 55 fractures were imaged. Comparison of CT and MRI showed sensitivity of 88%, specificity of 100% and positive predictive value of 100% for fracture union imaged with MRI using CT as the gold standard. Conclusion: MRI correlates well with CT in identifying vertebral fracture union and non-union. We suggest that where imaging is indicated in the assessment of vertebral body fracture healing MRI can be used routinely with CT reserved for problematic or inconclusive cases. IntroductionComputed tomography (CT) provides a basis for highly accurate and precise assessment of the three-dimensional structural parameters of bone. However, metallic artefacts can produce image distortions and the repeated use of CT also causes a cumulative radiation dose effect for the patient. Many patients with spinal injuries are young and the dose implications are greater in this population than in the older age group.Magnetic resonance imaging (MRI) has been used to evaluate for occult fractures and the presence of non-union. Fracture lines, continuity of marrow signal and the absence of bone marrow oedema as evidenced by signal change on MRI may indicate progression of fracture healing.Vertebral union after fractures or incorporation of graft can be particularly difficult to assess. Altered sensation causes further limitation in clinical assessment. We hypothesize that MRI can contribute significantly to this assessment by observing absence of increased T2-weighted signal with union and bridging across the fracture site on T1-weighted images. A diagnostic method that does not use ionizing radiation would be of particular value. BackgroundBone undergoes constant remodelling influenced by chemical, mechanical, cellular and pathological mechanisms.

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Quality of bone healing: Perspectives and assessment techniques

“…Magnetic resonance imaging (MRI) is another nondestructive imaging modalities used in the evaluation of bone quality . Although MRI shows good correlation to CT in clinical measures, care has to be taken if patients have metallic fixators or cardiac assist devices such as pacemakers. While high‐resolution MRI has been shown to determine trabecular structure to a certain extent, it has also been noted that these estimates are highly sensitive to image postprocessing, suggesting a greater possibility of errors without highly standardized protocols.…”

Comparative assessment of bone regeneration by histometry and a histological scoring system / Evaluarea comparativă a regenerării osoase utilizând histometria și un scor de vindecare histologică

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