Time-dependent diffusion in skeletal muscle with the random permeable barrier model (RPBM): application to normal controls and chronic exertional compartment syndrome patients.

The purpose of this work was to carry out diffusion tensor imaging (DTI) at multiple diffusion times Td in skeletal muscle in normal subjects and chronic exertional compartment syndrome (CECS) patients and analyze the data with the random permeable barrier model (RPBM) for biophysical specificity. Using an institutional review board approved HIPAA-compliant protocol, seven patients with clinical suspicion of CECS and eight healthy volunteers underwent DTI of the calf muscle in a Siemens MAGNETOM Verio 3 T scanner at rest and after treadmill exertion at four different T(d) values. Radial diffusion values λ(rad) were computed for each of seven different muscle compartments and analyzed with RPBM to produce estimates of free diffusivity D(0), fiber diameter a, and permeability κ.

Breast MRI at 7 Tesla with a bilateral coil and robust fat suppression.

Purpose: To develop a bilateral coil and fat suppressed T1-weighted sequence for 7 Tesla (T) breast MRI.

Materials And Methods: A dual-solenoid coil and three-dimensional (3D) T1w gradient echo sequence with B1+ insensitive fat suppression (FS) were developed. T1w FS image quality was characterized through image uniformity and fat-water contrast measurements in 11 subjects.

Breast MRI at 7 Tesla with a bilateral coil and T1-weighted acquisition with robust fat suppression: image evaluation and comparison with 3 Tesla.

Objectives: To evaluate the image quality of T1-weighted fat-suppressed breast MRI at 7 T and to compare 7-T and 3-T images.

Methods: Seventeen subjects were imaged using a 7-T bilateral transmit-receive coil and 3D gradient echo sequence with adiabatic inversion-based fat suppression (FS). Images were graded on a five-point scale and quantitatively assessed through signal-to-noise ratio (SNR), fibroglandular/fat contrast and signal uniformity measurements.

Stimulated echo diffusion tensor imaging and SPAIR T2 -weighted imaging in chronic exertional compartment syndrome of the lower leg muscles.

Purpose: To evaluate the performance of diffusion tensor imaging (DTI) in the evaluation of chronic exertional compartment syndrome (CECS) as compared to T2 -weighted (T2w) imaging.

Materials And Methods: Using an Institutional Review Board (IRB)-approved, Health Insurance Portability and Accountability Act (HIPAA)-compliant protocol, spectral adiabatic inversion recovery (SPAIR) T2w imaging and stimulated echo DTI were applied to eight healthy volunteers and 14 suspected CECS patients before and after exertion. Longitudinal and transverse diffusion eigenvalues, mean diffusivity (MD), and fractional anisotropy (FA) were measured in seven calf muscle compartments, which in patients were classified by their response on T2w: normal (<20% change), and CECS (>20% change).

Highly accelerated single breath-hold noncontrast thoracic MRA: evaluation in a clinical population.

Objectives: The objective of this study was to evaluate the performance of a highly accelerated breath-hold 3-dimensional noncontrast-enhanced steady-state free precession thoracic magnetic resonance angiography (NC-MRA) technique in a clinical population, including assessment of image quality, aortic dimensions, and aortic pathology, compared with electrocardiographically gated gadolinium-enhanced MRA (Gd-MRA).

Materials And Methods: After approval from the institution board and informed consent were obtained, 30 patients (22 men; mean age, 53.4 years) with known or suspected aortic pathology were imaged with NC-MRA followed by Gd-MRA at a single examination at 1.