We used 3D texture analysis of MRI relaxation times, combined with clinical outcomes, to evaluate the potential of repair cartilage with allogeneic human adipose-derived mesenchymal progenitor cells in patients with KOA. Significant differences were observed in texture RLM parameters of T1rho and T2 maps in patients. We also found correlations between WOMAC pain scores and texture parameters, suggesting the spatial heterogeneity of relaxation time maps maybe associated with clinical scores. As conclusion, texture analysis has potential applications in understanding mechanism of stem cells repairing cartilage and assessing response to treatment.

To assess the diagnostic performance of three-dimensional ultrashort echo time sequence (3D-UTE) in bone erosion detection of the sacroiliac joint (SIJ) in patients with clinically confirmed ankylosing spondylitis (AS) and to test whether SIJ cartilage T2* values might help in identification of patients with AS.

Diffusion tensor magnetic resonance imaging (DT-MRI) was used to investigate the three-dimensional architecture and diffusion properties of medial gastrocnemius muscles in living human infants aged 2-3 months. Mean muscle volume, physiological cross-sectional area and fascicle length in infants were 1.8%, 3.8% and 47.2% of values previously obtained in 8 adult muscles. Radial diffusivity in infant muscle was half that in adult muscle, presumably because infant muscle fibres have much smaller transverse dimensions.

Although the shorter scan time enabled by DLRecon has potential to reduce motion related image degradation, it cannot remove or mitigate such artifacts. The periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) or similar techniques can reduce motion artifacts in shoulder MRI, however usually takes a longer time to acquire. Recently, DLRecon for PROPELLER has been developed. Accelerated PROPELLER sequence with DLRecon showed improved image quality and comparable interobserver agreement for shoulder pathology compared to standard PROPELLER acquisition with conventional reconstruction, despite the shorter scan time (45% reduction).  

The automated detection of Intervertebral disc (IVD) herniation in animal MRI may facilitate veterinary diagnosis, yet it is rarely studied due to the lack of training data and the challenges from inter-breed variations. Here, we constructed a dog spinal cord MRI dataset with bounding box annotations of herniated discs, and conducted experiments using a number of well-known deep learning models. We demonstrated that automated detection of animal IVD herniation was feasible and in general two-stage detection models such as Faster R-CNN outperformed one-stage models.

Metastases and chordoma are both malignant tumors. When the manifestations are not typical, the two are prone to misdiagnosis. DWI using a biexponential model measured ADC, D, D*, and f. DWI using a stretched-exponential model obtained DDC, and α. DKI derived MD and MK. The monoexponential, biexponential, and stretched-exponential models of DWI and DKI have differential diagnostic value for spinal metastases and chordoma. Among the single parameter values, the D value has the highest AUC. Combining the values of three parameters (D, f, and α) can significantly improve the diagnostic efficiency of identifying spinal metastases and chordoma.

Fat content in lower limb is of highly clinical interest as it reflects physical activity. In this study, we quantified lower-limb fat content in a comprehensive way using a Dixon method. We found that fat content in lower limb generally decreased from pelvis to ankle. Of particular note, fat content in thigh was significantly higher than that in calf, and can potentially differentiate subjects with different body-mass index (BMI). It is also encouraging that fat content for a single cross-section at mid-thigh (30 sec scan time) approximated whole-limb fat content well, as it makes whole-body quantification in clinical setting feasible.

Alkaline inorganic phosphate (Pi_alk) is a promising biomarker of mitochondrial content in vivo that is technically challenging to assess at 3T. The absolute and relative reproducibility of Pi_alk in the quadriceps muscle across two visits were assessed in healthy sedentary-to-moderately active young adults using ³¹P-MRS at 3T. The results of this study demonstrate an excellent absolute and relative reproducibility of the quantification of Pialk in the quadriceps muscle at 3T provided that the coil is positioned at the mid-thigh. 

Diffusion-tensor imaging (DTI) based fiber tractography is a useful tool to study the architecture of human skeletal muscle. However, effects of image acquisition and analysis conditions on the outcome of architectural estimates are challenging to examine in vivo. In this work, we describe a numerical simulation framework where the ground truth of muscle architecture is known and the outcome can be tested under different conditions. Results show that the estimate of fiber curvature is most affected by image noise. While second-order polynomial fitting of fiber tracts is more robust to image noise, third-order fitting performs better on highly curved fibers.

Vegetarian nutrition may contribute for metabolic differences that we proposed to explore non-invasively. 6 omnivores and 6 lacto-ovo-vegetarians underwent a 7T MRI exam including proton and phosphorus magnetic resonance spectroscopy to measure creatine (tCr), phosphocreatine (PCr) and triglyceride components in the soleus muscle. tCr and unsaturated fatty acids concentration were reduced in vegetarians but similar PCr/γ-ATP ratios were found. We show that vegetarian diet induces lower skeletal muscle creatine and different lipid profiles, which was not associated with altered bioenergetic reserve. This protocol opens new avenues to explore the impact of diet in skeletal muscle.

To improve vascular suppression in 3D brachial plexus MR neurography (MRN) with FSE readouts, 3D directionally-selective crusher gradient technique was implemented. 3D Deep learning reconstruction (DLRecon 3D) with denoising and sharpening properties was applied to improve nerve conspicuity. Preliminary data showed that using both DLRecon 3D reconstruction and 3D crusher gradients resulted in improved image quality, image sharpness, and vascular suppression.

Three-dimensional statistical shape models built from MRI data can predict future disease and distinguish between groups. However, these models do not leverage the major advantage of MRI – the ability to visualize and quantify soft tissues such as cartilage. This study built three MRI-based statistical shape models, 1) bone shape, 2) cartilage thickness, 3) both bone shape and cartilage thickness. We showed that bone shape and bone shape + cartilage thickness models predicted sex with an R² of ~0.9, significantly outperforming cartilage thickness alone (0.8). However, cartilage thickness alone was significantly better at predicting radiographic knee osteoarthritis.

The 3D FSE sequence is widely used in clinical MRI for its capability to collect many phase encoding lines in each RF excitation. However, the signals during the long echo train readout are modulated by the T2 decay, resulting in blurring. An algorithm is presented to retrospectively demodulate estimated T2 decay from the actual signal. In the preliminary data, the proposed algorithm demonstrated success in deblurring the images.

We present a deep learning-based knee osteoarthritis grading system that automatically provides a binary classification for cartilage degeneration. The system was trained on MRI data sets applying MOAKS grading from the Osteoarthritis Initiative (OAI). The proposed method achieved an accuracy of 0.75 to 0.83, despite being conducted on highly imbalanced data sets. Significant improvement in accuracy is expected with more balanced data sets.

Evaluation of early-stage knee osteoarthritis (OA) has long been of wide concern, while MRI has proved its value in this field by the richness of contrasts and non-invasive nature. However, MRI detection for composition change in OA still calls for deeper researches. ADC and T₂ measured by conventional MRI are only an average of intra-voxel components and assumed to be independent. However, by performing a hybrid multidimensional MR imaging (HM-MRI) method, an implied correlation between ADC and T₂ in articular cartilage has emerged. Moreover, V_normal might offer extra information in detecting cartilage degeneration at early stage of OA than conventional ADC/T₂ parameters.

In knee MRI, patients with pain or limited motion can have difficult to endure a long-time imaging position. At the same time, the relatively high spatial resolution and good image quality were required in such musculoskeletal MRI. Therefore, shortening scan time and improving the image quality is the aim of current knee MRI.Our study compared conventional parallel imaging (PI) and artificial intelligence assisted compressed sensing (ACS) in terms of imaging quality and diagnostic performance in knee MRI, and achieved a 5-minute comprehensive examination of the knee, without compromising either image quality or visualization of anatomical and pathological structures.

This study aimed to quantify T1, T1rho, T2*, and MMF values of the human interspinous ligament using 3D ultrashort echo time (UTE) cones MRI and correlate them with biomechanical properties. We found a significant negative correlation between T1 and elastic modulus; significant moderate to strong negative correlations between T1rho and both tensile stress and maximum load; and significant moderate to strong positive correlations between MMF and both tensile stress and maximum load. There was an overall trend towards negative correlation between T2* and biomechanical properties.

Changes occurring in the bone-marrow fatty-acids (BMFA) could be precursors of the bone mineral loss due to the development of osteoporosis. In this view, early biomarkers of osteoporosis among BMFA could be highlighted by quantifying fatty-acids with 1H-MRS in young, premenopausal, postmenopausal women with normal t-score and in osteoporotic women. In this study, L13, L09, fUFA, and fPUFA together with TL quantification obtained in women calcanei  could be early osteoporosis markers. The present work confirms the potential of MRS to investigate BMFA metabolic variations due to postmenopause and to the development of osteoporosis.