Jules Nelissen, Dorien Verschuren, Maurits Sloots, Larry de Graaf, Jitsha Monte, Sandra van den Berg, Kevin Moerman, Klaas Nicolay, Mario Maas, Sicco Bus, Ralph Sinkus, Jurgen Runge, Christof Smit, Thomas Janssen, Cees Oomens, Gustav Strijkers, Aart Nederveen

Gluteus maximus biomechanical properties and composition are altered in spinal cord injured (SCI) subjects and increase the risk of deep tissue injury type of pressure ulcers. For this purpose, a multi-parametric MRI study of the gluteus maximus of SCI and able-bodied subjects was performed. The protocol consisted of MRE, T₂-mapping, and Dixon. The gluteus maximus of SCI subjects had a lower stiffness, which was accompanied by a higher fat fraction, as compared to the able-bodied subjects. The proposed protocol has great potential in providing personalized information on deep tissue injury risk.

Rajiv Menon, Preeti Raghavan, Ravinder Regatte

In this study, we evaluate the use of 3D-T1rho (T1ρ) relaxation mapping of the upper arm muscle glycosaminoglycan (GAG) content in healthy controls, and post stroke patients with pre and post hyaluronidase injections. Healthy controls (n=5) and post-stroke patients (n=5, pre and post treatment) were recruited. Dixon based  water-fat imaging and T1ρ mapping were performed. Mono- and bi-exponential modeling was used to process the data. While water-fat distributions were not significantly different between the two groups, significant differences were noted in T1ρ values using mono- and bi-exponential analysis. T1ρ imaging shows significant changes that reflect the reduction of GAG’s following the treatment with hyaluronidase injection.

Sarah Schlaeger, Dominik Weidlich, Elisabeth Klupp, Federica Montagnese, Marcus Deschauer, Benedikt Schoser, Sarah Bublitz, Claus Zimmer, Ernst Rummeny, Jan Kirschke, Dimitrios Karampinos

In patients with neuromuscular diseases muscle water T2 is an important biomarker to monitor disease activity and therapy effectiveness. Especially, the thigh is of interest showing disease-characteristic patterns of involvement. Different T2 mapping approaches, routinely based on MESE, have been developed to minimize the effect of confounding factors. An alternative method is the T2Prep 3D-TSE combined with SPAIR. However, it remains unknown, how T2Prep 3D-TSE performs in the presence of fat. This work simulates the effect of SPAIR and T2preparation on the 3D-TSE readout in the presence of fat and compares T2Prep 3D-TSE and 2D-MESE to MRS in 34 patients.

M.T. Hooijmans, C. Baligand, M. Froeling, J.J.G.M Verschuuren, A.G. Webb, E.H. Niks, H.E. Kan

Quantitative MR is increasingly used to assess muscle damage in muscular dystrophies, including BMD. Early markers that reflect changes in muscle tissue are becoming increasingly important with therapies aimed at preserving muscle tissue. This study used a multi-modal MR approach to examine diffusion properties,  the average water T2 and SD of the water T2 in non-fat-infiltrated and fat-infiltrated muscles in BMD. Our results indicate that none of the proposed measures are sensitive to muscle tissue changes prior to the replacement of muscle tissue by fat and that only T2 heterogeneity is sensitive to muscle tissue changes in the presence of fat in patients with BMD. 

Bauke Kogelman, Kevin Adamzek, Ernst Suidgeest, Gustav Strijkers, Maaike Putten, Louise Weerd

A T1Rho sequence was used in a Duchenne Muscular Dystrophy mouse model characterized by increased muscle fibrosis. Significantly higher T1Rho relaxation times were found compared to wild-type mice in which fibrosis was absent. Although both T1Rho and T2 values were increased, the increase was more pronounced for T1Rho than for T2 (14.2% vs 3.6%), indicating that T1Rho is affected by other processes than those resulting in increased T2 values. These data demonstrate the potential of T1Rho to assess muscle fibrosis in vivo. 

Benjamin Marty, Pierre Carlier

Quantitative T1-mapping might represent an efficient tool to monitor inflammation, necrosis or fibrosis processes in skeletal muscle tissues affected by neuromuscular disorders. However, standard T1-mapping sequences cannot separate the contribution of water and fat protons. If directly applied to fatty infiltrated skeletal muscles, a “global” T1 value would mainly reflect the degree of intramuscular fat and the other underlying processes would largely be hidden. Here, we proposed an optimal sequence allowing simultaneous estimation of water T1 and fat fraction. It was validated in phantom and in vivo acquisitions were performed on several subjects suffering from different neuromuscular diseases.

Fengdan Wang, Qian Wang, Haiping Zhang, Dong Liu, Tobias Kober, Tom Hilbert, Yi Sun, Yan Zhang, Zhengyu Jin

We investigated the use of the T2 mapping technique to quantitatively evaluate the thigh muscles of 18 dermatomyositis (DM)/polymyositis (PM) patients and 10 healthy control subjects. Moreover, the correlation of T2 values with apparent diffusion coefficient (ADC) values was also studied. The results showed significantly elevated T2 values with edematous muscles and increased T2 values with unaffected muscles (normal appearing in conventional MRI) in DM/PM patients, compared to the control group. The T2 values of the edematous muscles were found to be closely correlated with the ADC. This study demonstrated that T2 mapping may be successfully used in the quantitative evaluation of inflammatory myopathy.

John Biglands, Steven Tanner, Ai Lyn Tan, Sarah Mackie, Elizabeth Hensor, John Ridgway, Paul Emery, Thorsten Feiweier, Emma Harris, Paul Stewart, Andrew Grainger

The purpose of this study was to assess differences in fat fraction and water diffusion between muscles in the healthy thigh and to assess differences between glucocorticoid treated patients with polymyalgia rheumatic (PMR) and healthy controls. Twenty five healthy volunteers and sixteen patients with PMR undergoing glucocorticoid treatment underwent MRI to assess muscle fat fraction and diffusion. The study found that the hamstrings have greater fat fraction and reduced diffusion compared to quadriceps in healthy individuals. Furthermore, alterations in fat fraction and diffusion parameters associated with glucocorticoid-treated PMR are more readily detectable in the hamstrings than the quadriceps. 

Linda Heskamp, Franciska Lebbink, Mark van Uden, Marnix Maas, Jurgen Claassen, Andreas Boss, Arend Heerschap

Since the rate of phosphocreatine recovery after exercise varied substantially within the tibialis anterior, we wondered if O₂ supply also varied along this muscle. Therefore, we applied near infra-red spectroscopy to study the dynamic equilibrium of O₂ supply and O₂ utilization, intravoxel incoherent motion imaging for muscle perfusion and ³¹P-MRS during and after isometric exercise of the tibialis anterior. We observed higher post-exercise perfusion and faster phosphocreatine and oxyhemoglobin recovery proximally than distally in the tibialis anterior, indicating a proximo-distal gradient in O₂ supply. This may be an adaptation to a higher proximal energy requirement.

Eric Sigmund, Steven Baete, Mary Bruno, David Stoffel, Jenny Bencardino

We describe measurement of work dependence of exercise response of diffusion contrast in calf muscle with a multiple echo diffusion tensor imaging (MEDITI) in a clinical 3 T scanner.  With radial imaging, accelerated diffusion encoding, and compressed sensing reconstruction, spatial resolution of 3.7 mm and temporal resolution of 16 s was achieved.  Using an MR-compatible ergometer with pneumatic resistance and force/displacement monitoring, post-exercise recovery of T2 and DTI metrics following plantarflexion in gastrocnemius muscle were monitored as a function of total normalized work.  Exercise response showed significant anisotropy, and trends of higher response with work were observed.