Comparison Between CT and MRI in Preoperative Evaluation of Neurogenic Myositis Ossificans or Neurogenic Para-osteo-arthritis

Preoperative Evaluation of Neurogenic Myositis Ossificans or Neurogenic Para-osteo-arthritis: Comparison Between Computed Tomography and Magnetic Resonance Imaging in Preoperative Evaluation

The principal objective of the study is to compare between CT and MRI diagnostic performance (sensibility and specificity) in the preoperative assessment of neurogenic para-osteo-arthritis.

The second objectives of the study are:

• besides the diagnostic performance (sensibility and specificity), to evaluate the imaging par MRI in visual and descriptive manner heterotopic ossification and connection with vascular and nervous structures.
• to study the concordance (two by two) of results of preoperative obtained by MRI and by CT and operative reports.
• to study the characteristics of patients with discordant findings (two by two) by MRI, CT scan and operative report.

This is a study on diagnostic performance, non randomized, versus Gold standard (a prospective multicentric cohort).

All eligible patients will be proposed consecutively to participate to the study, to undergo preoperative CT scan and MRI examination as usual procedure. The only additional action in this study will be a neurography sequence of type fluorescence subtraction imaging (FSI) during MRI, permitting to obtain more details in visualization of nerve structure and their relations of the ossifications.

The enrollment visit will performed by neuro-orthopaedic surgeon during preoperative consultation.

The follow-up visit will be an usual post-operative visit, non-specific for the study.

The duration for each participant will compound 1 month (the duration between preoperative imaging and surgical resection) added by up to two months of post-operative follow-up.

Inclusion Criteria:

• Adult patient with neurogenic para-osteo-arthropathy resulted by prior central nervous system, cerebral or medullar damage
• Deformation with limitation of articular amplitude which could result limitation in rehabilitation care
• An indication of partial or total surgical excision of heterotopic ossification
• Indication of pre-operative assessment by CT scan and MRI, with contrast product injection
• Signed consent of patient obtained after clear and relevant informations given by physician
• Patient covered by social security

Exclusion Criteria:

• Contraindications to an MRI examination: cardiac stimulator, metallic intraocular foreign bodies...
• Contraindications to CT scan
• Contraindications to contrast injection product, such as iodinated or gadolinium-based contrast media
• Impractical venous access
• Severe deformation resulting impossibility to positioning for MRI examination or CT scan
• Patient can not give consent
• Participation to another interventional study
• Patient under guardianship