Bone microarchitecture is an important contributor to its strength, and landmark high-resolution MRI studies have provided strong evidence that its deterioration may explain differences in individuals’ fracture risk.

We use a custom radio frequency coil array on a 7 Tesla MRI platform to acquire exquisite microarchitecture images in the proximal femur, which has been difficult because of the small size of the trabeculae (~20um) and their deep position in the body. Our images are then processed with finite element analysis tools to determine bone strength.

 

Breast MRI at 7 Tesla is driven by the promise of improved SNR, which is advantageous for morphologically-based lesion diagnosis but comes with technical challenges stemming from the non-uniform magnetic field.

We address 7 Tesla technical hurdles with a custom bilateral coil and SPAIR fat suppression to provide high-resolution images with excellent water/fat contrast. The SNR advantage provided by our bilateral coil at 7 Tesla allowed allowed visualization of dendritic patterns and ligaments in images with 0.6-mm isotropic resolution. The same structures are difficult to visualise in clinical magnets. In a small cohort, we found that our customize 7 Tesla protocol resulted in significantly higher image quality scores for high-resolution breast imaging compared with 3 T.

 

We showed that 7-Tesla shoulder MRI is feasible with a custom radio frequency array either in single-channel or parallel-transmit mode. Our hardware provided more than two-fold SNR advantage over the conventional system.

We were able to translate most of our 3-Tesla clinical shoulder protocols to 7-Tesla. The images provided clear delineation of both articular cartilage layers and the anterior and posterior labra. We can diagnose Injuries such as a labral tears, fluid in the shoulder joint, hypertrophy of the anterior labrum, subchondral cyst formation, and thin glenoid cartilage.

7-T anatomical shoulder images. A to C, 0.7-mm isotropic 3D-GRE. D, PDw FSE depicts the sublabral foramen (white arrow) and anterior and posterior labra (black arrows). The articular cartilage can be visualized in D, E, and G (opposed black arrows). E, T2w FSE reveals irregularity of the anterior labrum likely reflecting a partial tear (double white arrow). Lack of signal is observed in the peripheral muscles (black arrowhead), likely caused by high B1+. F, normal T1w TSE. G, Normal deltoid origin (double black arrow), supraspinatus tendon (white arrowhead), and interface between the glenoid and humeral head articular cartilages (opposed black arrows). H, Hypertrophy of the anterior labrum (black closed arrow), posterior labral tear (white arrow), subchondral cyst formation (black open arrow), and thin posterior glenoid cartilage (black arrowhead), the latter of which may be related to posterior subluxation of the humeral head. I, Partial-thickness articular surface tear of the posterior fibers of the supraspinatus (black arrowhead) and a subcortical cyst (double black arrow). J, Osteoarthritis manifested by cartilage thinning and osteophyte formation (ellipse) and a healed fracture deformity involving the greater tuberosity and surgical neck of the humerus (bracket).

7-T anatomical shoulder images. A to C, 0.7-mm isotropic 3D-GRE. D, PDw FSE depicts the sublabral foramen (white arrow) and anterior and posterior labra (black arrows). The articular cartilage can be visualized in D, E, and G (opposed black arrows). E, T2w FSE reveals irregularity of the anterior labrum likely reflecting a partial tear (double white arrow). Lack of signal is observed in the peripheral muscles (black arrowhead), likely caused by high B1+. F, normal T1w TSE. G, Normal deltoid origin (double black arrow), supraspinatus tendon (white arrowhead), and interface between the glenoid and humeral head articular cartilages (opposed black arrows). H, Hypertrophy of the anterior labrum (black closed arrow), posterior labral tear (white arrow), subchondral cyst formation (black open arrow), and thin posterior glenoid cartilage (black arrowhead), the latter of which may be related to posterior subluxation of the humeral head. I, Partial-thickness articular surface tear of the posterior fibers of the supraspinatus (black arrowhead) and a subcortical cyst (double black arrow). J, Osteoarthritis manifested by cartilage thinning and osteophyte formation (ellipse) and a healed fracture deformity involving the greater tuberosity and surgical neck of the humerus (bracket).