CP #7: Identification of Novel Imaging Biomarkers of Osteoarthritis via 23Na/1H MRI at 7T

Identification of Novel Imaging Biomarkers of Osteoarthritis via 23Na/1H MRI at 7T

Significance:

The goal of this project is to use ultra-high field 7 Tesla MRI to identify novel microstructural and biochemical imaging biomarkers of osteoarthritis (OA) that may aid in the early detection of OA and enable improved monitoring and prediction of disease progression.  OA is manifested by degeneration in articular cartilage (initially decreased proteoglycan content, followed by reduced thickness) and damage to subchondral bone (microfractures, osteophytosis) [1]. It remains unclear whether the initial insult occurs in cartilage, resulting in damage to subchondral bone, or vice versa [1,2].  Radiographs – the current imaging gold standard utilized for OA diagnosis and disease monitoring in clinical trials – cannot directly visualize cartilage and are insensitive to changes in subchondral trabecular bone micro-architecture [3].  And while conventional MRI (1.5-3 Tesla) can reveal macroscopic structural alterations present within multiple joint tissues in subjects with OA (bone attrition, partial width cartilage defects), these changes are irreversible when detected [3,4]. In preliminary studies, we have demonstrated the ability of the high-resolution proton MRI at 7T to detect subtle alternations in subchondral bone microarchitecture and cartilage thickness in the knees of subject with osteoarthritis (Figure 1).

Aims:

In this study, we will determine whether 7T MR measures of cartilage and bone can detect disease presence and disease severity by distinguishing healthy from early OA subjects, and early OA from advanced OA subjects. We will then determine whether longitudinal changes in 7T MR measures of cartilage and bone are indicative of OA progression, and will ultimately determine whether baseline values of 7T MR measures of cartilage and bone predict OA progression.

Approach:

7T MR will be used to detect decreases in cartilage measures (thickness, volume, and sodium content) and differences in trabecular bone micro-architecture (increased trabecular thickness, number, plate-to-rod ratio, connectivity; decreased trabecular separation) in: 1) early OA (Kellgren-Lawrence radiographic grade 1-2) compared to healthy subjects and 2) advanced OA (Kellgren-Lawrence 3-4) compared to early OA subjects.  A 3-year longitudinal study will be performed to correlate longitudinal changes in 7T MR measures of cartilage and trabecular bone micro-architecture to radiographs (joint space width), conventional MRI (Whole Organ MRI Score) and clinical questionnaires (WOMAC scores).  Linear regression analysis will be performed to determine whether baseline 7T MR measures predict worsening JSW, WORM, or WOMAC scores.

Push-Pull Relationship with TR&D Projects #1 & 2: 

TR&D#1: As we have already demonstrated in preliminary collaborative work, compressed sensing will improve our 3D ultra-short TE acquisitions for cartilage sodium imaging at 7T [5].  Compressed sensing techniques will also benefit our high-resolution 7T proton MRI evaluation of cartilage and subchondral bone microstructure [6-9], and expected reductions in imaging time would enable multiparametric 1H and 23Na examination in a clinical time slot.  Meanwhile, this project will drive BTRC development in the challenging application area of cartilage imaging, which involves a restricted anatomical area of interest in which small artifacts may have a significant impact, and which requires detailed clinical feedback.

TR&D#2: The development of novel RF detectors and transmitters for multinuclear imaging will also directly benefit this project.  Since the original submission, building on our prior 7T MSK coil developments [9,10], we have already performed and published collaborative work on new efficient 7T coil arrays for microstructural evaluation of the knee [11] and other joints [12,13]. Such coils will permit us to better detect early biochemical degeneration in cartilage as a tissue, which is considered a technical holy grail of advanced biochemical cartilage MRI.  Meanwhile, the anatomical constraints imposed by cartilage imaging will serve as specific drivers for novel UHF RF hardware. Effective feedback on the efficacy of coil designs for this area can only originate from a project that is focused on this anatomy.  

Principal Investigator: 

Sponsors

Latest Updates

10/31/2017 - 11:54
10/31/2017 - 11:37

Philanthropic Support

We gratefully acknowledge generous support for radiology research at NYU Langone Medical Center from:
 
• The Big George Foundation
• Raymond and Beverly Sackler
• Bernard and Irene Schwartz

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