Magnetic Resonance Imaging in High Risk Patients for the Development of Diffuse Idiopathic Skeletal Hyperostosis (DISH)

Overview

Diffuse idiopathic skeletal hyperostosis (DISH) is a poorly understood, systemic condition characterized by progressive calcification and ossification of ligaments and entheses. The current classification criteria allow diagnosing the disease in its late course, when significant bony overgrowth already involves the vertebral column and the appendicular skeleton. The research of the pathogenic mechanisms in DISH, is significantly hampered by the late diagnosis resulting from this definition.Based on recent MRI studies in both axial spondyloarthritis (axSpA) and in DISH, it seems that changes similar to the classical early inflammatory changes described in axSpA, can be detected in patients with DISH. We therefore hypothesize, that patients with metabolic syndrome without radiographic evidence for spinal DISH, might exhibit early MRI changes. If this hypothesis proves to be correct, early diagnosis and research of the possible pathogenetic mechanisms at this early stage might be very rewarding in investigations of the early aberrations of the entheses homeostasis and eventually early, more targeted therapeutic interventions. The study will examine MRI changes in patients, in their 5th decade of life, with high risk for the development of DISH (ie diabetes mellitus, metabolic syndrome) compared with patients who don't have this risk.

Patient's selection- Patients will be recruited from obesity/metabolic/diabetes clinics and from bariatric surgeries clinics. All patients will have the diagnosis of metabolic syndrome National Cholesterol Education Panel III (NCEP). Patients in their 5th decade of life will be recruited for the study. This study group will have to meet the NCEP 3 criteria for metabolic syndrome and/or have type 2 diabetes mellitus (9). An age and sex matched individuals who do not meet these pre-requisits will serve as a control group. All asymptomatic patients will undergo postero-anterior and lateral x-rays of the thoracic spine, unless they have postero-anterior or lateral thoracic spine or chest x-rays in the year preceding the recruitment. For patients with back pain, addition of cervical or lumbar spine radiographs will be permitted based on the physician judgement. Patients recruited for the study will have a total spine and sacroiliac MRI (see below) read by radiologists and rheumatologists, expert in musculoskeletal imaging, who will be blinded for the patient's data. The readings of the radiographs and the MRI will be performed in a random order. All patients and controls will undergo postero anterior and lateral thoracic spine X-rays and MRI of the entire spine and their sacroiliac joints (Spine: sagittal T1-weighted and T2 with fat suppression sequences, SIJ semicoronal T1-weighted and T2 with fat suppression sequences) at study entry. An accepted scoring system for the interpretation of the MRI studies will be employed for both the spine and the sacroiliac joints.