3T MR Fingerprinting of Early Stage OA Patients

Our hypothesis is that MR Fingerprinting (MRF) a new technical and methodological approach in MR imaging will offer a fast single fast sequence for the evaluation of osteoarthritis of the knee joint which may replace several conventional MR sequences, used so far in a knee MR protocol. The simultaneously acquired quantitative T1 and T2 relaxation time maps by MRF may offer information on the early stages of osteoarthritis, which so far can only be gained from a conventional advanced knee joint MR protocol. In this planned follow up study an enhanced evaluation of the progress of osteoarthritis should be possible by MRF. Methods to proof these hypotheses will comprise the following phases: 1) Phantom testing of the MRF acquired T1 and T2 relaxation time maps and the conventionally acquired T1 and T2 relaxation times 2) in vivo application of the validated MRF sequence and protocol optimization on 10 volunteers with test-retest evaluation 3) in vivo application of MRF on 40 patients with high risk for osteoarthritis (20 after partial meniscectomy, 20 after anterior cruciate ligament tears) and a follow-up with high reproducibility by the use of automatic cartilage segmentation and subdivision of the knee joint into 21 subfields and coregistration with T1 and T2 maps. We hypothesize that MRF-obtained T1 and T2 relaxation times and synthetically generated contrast images of the knee joint in one MR sequence of 5 minutes will provide similar information on patients with early osteoarthritis compared to a conventional advanced knee joint MR protocol which takes about 40 minutes.

This project focused on developing and evaluating an advanced MRI technique called Magnetic Resonance Fingerprinting (MRF) to improve imaging of knee cartilage. Cartilage plays a key role in joint function by cushioning movement and distributing loads. Damage to this tissue is one of the earliest signs of osteoarthritis (OA), a widespread and disabling joint disease. Detecting such changes early, before symptoms become severe or permanent, is crucial for enabling timely treatment and possibly preventing disease progression. Quantitative MRI, particularly T2 mapping, has emerged as a promising non-invasive method to assess cartilage health. However, conventional T2 mapping techniques are time-consuming and often require multiple scans for each tissue parameter, making routine clinical use challenging-especially when evaluating the entire knee or multiple structures. MRF offers a breakthrough by enabling simultaneous, rapid measurement of multiple tissue properties in a single scan. To explore its potential, we developed a comprehensive MRI protocol combining MRF with standard quantitative and clinical imaging methods. The sequence was tested in a structured, multi-phase process. First, we conducted phantom experiments to assess the technical performance of the MRF sequence. Next, we scanned healthy volunteers to evaluate how well MRF performs in vivo. A subset of these participants underwent test-retest imaging to measure repeatability. We also created a fully automated analysis pipeline to assess the entire cartilage volume efficiently and consistently. In the final study phase, we recruited patients with focal cartilage damage, capturing both whole-cartilage and lesion-specific data. Importantly, these patients were also scanned one year later, allowing us to test MRF's ability to monitor longitudinal changes in cartilage composition. Our findings demonstrate that MRF produces highly accurate and reproducible T2 maps of knee cartilage, enabling the assessment of regional variability of T2 across cartilage as well as assessment from lesion regions. These maps allow visualization of early tissue changes that may precede visible structural damage, potentially improving early diagnosis and personalized treatment of OA. While some limitations remain-particularly related to spatial resolution and the anatomical complexity of the thin cartilage layers-MRF proved to be a fast, multiparametric method with strong potential for use in clinical musculoskeletal imaging. Its ability to efficiently assess both the whole joint and localized lesions in a single session represents a meaningful step forward in MRI technology. This work lays a foundation for broader application of MRF in musculoskeletal health and supports its further development for non-invasive, quantitative assessment of joint disease.