Quatitative MRI of the Spinal Cord in Cervical Myelopathy: Assessment of Microstuctural Damage for Outcome Improvement

Rationale Degenerative cervical myelopathy (DCM) is a common chronic disorder and the most common cause of spinal cord dysfunction in adults, potentially leading to severe functional impairment with high social costs. More than 70% of people younger than 65 years have pathologic or radiologic evidence of cervical degenerative disease. Symptoms of cervical compression develop in about 25% of these people. Consequently, identifying optimal treatment strategies and clinical care pathways for DCM has become a key public health priority. DCM is caused by a progressive deterioration of osseocartilaginous components of the cervical spine leading to a narrowing of the spinal canal and compression of the long tracts and local segmental elements of the Spinal Cord (SC). DCM can lead to progressive disability and paralysis owing to chronic SC compression.

In DCM, an early diagnosis and monitoring are pivotal to avoid or constrain a neurological damage that may persist even after appropriate treatment is provided. Diagnosis of DCM requires agreement between clinical and imaging findings (MRI).

Quantitative MRI of the SC could provide a new objective system for identification of patients who require surgery before developing irreversible clinical damage, and to avoid surgical treatment in those who do not require it. Additionally, quantitative MRI, in combination with clinical data such as, neuromotor tests, could provide an important approach to assess the effectiveness of the therapeutical approach.

The plan with this project is to validate a newer clinically feasible quantitative MRI protocol to depict spinal cord microstructural changes determined by degenerative cervical spine disease, that is highly frequent in the adult population. Investigators are confident that to identify quantitative MRI-derived metrics that could objectively quantify spinal cord damage in degenerative cervical myelopathy, and that could depict microstructural modifications even before neurological signs or signal alterations on morphological MRI sequences are evident. This could be of pivotal importance for more precise indication to surgery and to prevent clinically significant damage that might not be recovered even after surgical treatment. These data will be measured and validated by neurophysiological findings, and compared to current scales and ad-hoc battery of neuromotor skill assessment tests.

Clinical, neurophysiological, biometric and imaging follow-up will be performed to assess the predictive power of the identified metrics.

This study aims to provide a new paradigm for improved depiction of the effects of degenerative cervical spondylosis that could become crucial for an individualized and timely therapeutic decision. In DCM, an early diagnosis is pivotal to avoid neurological damage that may persists even after appropriate treatment is provided. More accurate, integrated clinical, imaging and functional evaluation is also advocated to improve the detection of subtle signs of sensory-motor disturbances, and for increasing the inter-rater and intra-rater reliability of available scales. In the proposed study, for the first time the aim is to: i) integrate T1-based (PSIR, TI-scout) and DTI metrics; ii) compare them to clinical, neurophysiological and neuromotor skill performances, and iii) perform longitudinal pre- and post-operative (ACDF) evaluation.

One important aspect to mention is that this study is performed for the first time, given the availability of the new-generation polyetheretherketone (PEEK) and carbon fiber surgical hardware which allow the acquisition of the advanced quantitative MRI sequences without significant image distortion even when anterior cervical discectomy and fusion (ACDF) is performed.

Through an artificial intelligence approach, investigators also expect to develop a new objective scoring system that will include relevant items from MRI-derived metrics and clinical, neurophysiological and neuromotor skills data. Investigators foresee that the new scoring system could help clinician in identifying patients with the highest risk of progressing to irreversible neurological damage, and that could overcome the limitations of the available clinical scales, that include poor sensitivity and modest inter-rater and intra-rater reliability with limited ability to detect subtle disease progression.

Therefore, the expectation is to identify more objective and sensitive metrics of spinal cord disease burden through the identification of sensitive, objective and quantitative biomarkers of neurological damage in DCM.

The results of this project will provide a new reliable system for identifying patients at risk of progressing to irreversible functional impairment, leading to a patient-centered approach, a cost-effective prevention of neurological deficits, and a cost-effective avoidance of unnecessary surgical interventions.

Objectives

This is a multi-disciplinary study with a focus on subjects affected by cervical spondylosis (DCM) determining several degrees of myelopathy, from mild to severe. The study is aimed at identifying an enhanced clinical, radiological and neuromotor skills evaluation at presentation, seeking to early identify and quantify the disease burden, likely through the depiction and validation of new neuroradiological and functional metrics. This is meant to also tailor and strengthen the indication for surgery, in order to depict microstructural degeneration before signs and symptoms presentation or worsening, since neurological damage may persist even after appropriate treatment has been provided. Additionally, findings from magnetic resonance in combination with neuromotor assessment could be beneficial for patient monitoring after surgery.

Primary objective To implement and validate a novel qMRI protocol clinically for the identification and quantification of microstructural SC damage Secondary objective To compare and correlate clinical and neurophysiological data and detailed movement analysis (overall mobility, walking performance, postural stability, spasticity, upper limb dexterity, detailed movement analysis) with qMRI-derived metrics.

Tertiary objective To elaborate an integrated diagnostic innovative tool for early diagnosis and disease monitoring of myelopathy, and for identification of a more reproducible and quantitative scale for assessing reversible and irreversible spinal cord damage combining clinical, biometric and imaging (qMRI) data assessed at short (1 month) and long-term (6 months) follow-up and neurophysiological data at long-term (6 months) follow-up in patients who underwent either surgical or non-surgical treatment.

The following aims will be pursued to identify more objective and sensitive metrics of the disease burden and prevent the neurological damage from overcoming a clinical threshold.

Primary endpoint Quantitative MRI metrics Secondary endpoint

To combine:

• qMRI data.
• Clinical data (mJOA and Barthel Index).
• Neurophysiologic data (Somatosensory evoked potential (PESS) and Motor evoked potential (MEP)).
• Neuromotor skill assessment (upper and lower limb) Tertiary endpoint Through an artificial intelligence approach above mentioned clinical, biometric, neurophysiological and imaging data assessed at short (1 month) and long-term (6 months) follow-up in patients who underwent either surgical or non-surgical treatment will be combined in order to obtain an enhanced integrated diagnostic powerful tool for early diagnosis and disease monitoring od myelopathy, and for identification of a more reproducible and quantitative scale for assessing reversible and irreversible spinal cord damage.

STUDY POPULATION The propose is a multicentric, prospective, longitudinal study classified as low interventional, enrolling 100 adult subjects with a single-level degenerative spondylosis of the sub-axial cervical spine (C3-C7) as diagnosed on a combination of symptoms, signs and conventional MRI findings.

Patient will undergo:

• MRI (baseline - 1 month- 6 months)
• clinical data collection (baseline- 1 month - 6 months)
• neuromotor assessment (baseline - 1 month - 6 months)
• neurophysiological assessment (baseline - 6 months)
• surgery if applicable The therapeutical treatment would remain standard. No additional imaging sessions will be added in relation to the standard diagnostic and monitoring protocol. Diagnostic MRI will be integrated with advanced sequences which pose no harm for patients and only extend the diagnostic procedure of an interval between 10 and 15 minutes. In addition to traditional practice, patients will receive ad-hoc neuromotor assessment from physical therapists with advanced software for motion analysis.