Detection of early metaphyseal changes in a piglet model of Legg-Calvé-Perthes disease using quantitative mapping of MRI relaxation times.

Legg-Calvé-Perthes disease (LCPD) is a childhood hip disorder characterized by ischemic injury to the epiphysis of the femoral head, but changes to the metaphysis have also been implicated in its pathogenesis. Quantitative magnetic resonance imaging (MRI) relaxation time mapping techniques are potentially useful to detect injury in LCPD, but studies to date have focused on the epiphysis. The purpose of this study was to assess whether T2, T1ρ, adiabatic T1ρ, and adiabatic T2ρ relaxation times can detect early metaphyseal changes in an LCPD piglet model.

Locally low-rank denoising in transform domains.

Purpose: To develop an extension to locally low rank (LLR) denoising techniques based on transform domain processing that reduces the number of images required in the MR image series for high-quality denoising.

Theory And Methods: LLR methods with random matrix theory-based thresholds are successfully used in the denoising of MR image series in a number of applications. The performance of these methods depend on how well the LLR assumption is satisfied, which deteriorates with few numbers of images, as is commonly encountered in quantitative MRI applications.

Epiphyseal cartilage vascular architecture at the distal humeral osteochondritis dissecans predilection site in juvenile pigs.

Failure of endochondral ossification due to interruption of the vascular supply to the epiphyseal cartilage is a critical step in the development of osteochondritis dissecans (OCD). Herein we describe the vascular architecture of the distal humeral epiphyseal cartilage in pigs and identify characteristic features that have been associated with sites predisposed to OCD development across species. Distal humeral specimens were harvested from pigs (n = 5, ages = 1, 10, 18, 30, and, 42 days old) and imaged at 9.

Macrophages and Intervertebral Disc Degeneration.

The intervertebral disc (IVD) aids in motion and acts to absorb energy transmitted to the spine. With little inherent regenerative capacity, degeneration of the intervertebral disc results in intervertebral disc disease, which contributes to low back pain and significant disability in many individuals. Increasing evidence suggests that IVD degeneration is a disease of the whole joint that is associated with significant inflammation.

Mitral Valve Flow and Myocardial Motion Assessed with Dual-Echo Dual-Velocity Cardiac MRI.

Purpose: To develop a dual-echo phase-contrast (DEPC) MRI approach with which each echo is acquired by using a different velocity sensitivity within one repetition time (TR) and demonstrate the feasibility of this approach to measure transmitral blood flow and myocardial tissue ( ) velocities.

Materials And Methods: The flow across tubes of known diameter was measured by using the proposed DEPC method and compared with flowmeter measurements and theoretic predictions. Then, with both the DEPC MRI sequence and the conventional single-echo phase-contrast (SEPC) MRI sequence, , and were measured in six healthy volunteers (mean age, 49 years ± 13 [standard deviation]) and eight patients (mean age, 54 years ± 15) being evaluated for cardiac disease.