Clinical Translation of Three-Dimensional Scar, Diffusion Tensor Imaging, Four-Dimensional Flow, and Quantitative Perfusion in Cardiac MRI: A Comprehensive Review.

Cardiovascular magnetic resonance (CMR) imaging is a versatile tool that has established itself as the reference method for functional assessment and tissue characterisation. CMR helps to diagnose, monitor disease course and sub-phenotype disease states. Several emerging CMR methods have the potential to offer a personalised medicine approach to treatment. CMR tissue characterisation is used to assess myocardial oedema, inflammation or thrombus in various disease conditions. CMR derived scar maps have the potential to inform ablation therapy-both in atrial and ventricular arrhythmias. Quantitative CMR is pushing boundaries with motion corrections in tissue characterisation and first-pass perfusion. Advanced tissue characterisation by imaging the myocardial fibre orientation using diffusion tensor imaging (DTI), has also demonstrated novel insights in patients with cardiomyopathies. Enhanced flow assessment using four-dimensional flow (4D flow) CMR, where time is the fourth dimension, allows quantification of transvalvular flow to a high degree of accuracy for all four-valves within the same cardiac cycle. This review discusses these emerging methods and others in detail and gives the reader a foresight of how CMR will evolve into a powerful clinical tool in offering a precision medicine approach to treatment, diagnosis, and detection of disease.

Advanced MR Imaging Techniques for Differentiation of Neuropathic Arthropathy and Osteomyelitis in the Diabetic Foot.

Diagnosis and treatment of foot disease in patients with diabetes is a common clinical-radiologic challenge, particularly the differentiation of neuropathic arthropathy from osteomyelitis. Conventional clinical tests and imaging techniques have limited accuracy for evaluation of the diabetic foot. The introduction of morphologic magnetic resonance (MR) imaging in these patients has provided a qualitative leap in diagnosis. The characteristics of soft-tissue and bone marrow edema and their patterns of distribution throughout the foot allow discrimination between both entities. However, in certain scenarios, the application of MR imaging to this problem is limited because of overlapping features between the two and the coexistence of infection and neuropathic changes. Recent technical advances in MR imaging sequences have increased the capability to add functional quantitative information to structural information. Diffusion-weighted imaging is useful to determine the presence and extension of osteomyelitis. Dynamic contrast-enhanced MR imaging may help to detect differences between the vascularization patterns of neuropathic arthropathy and osteomyelitis. MR angiography (with or without contrast material) is used in clinical practice to identify candidate distal vessels for revascularization. MR neurography, and especially diffusion-tensor imaging, provides quantitative information about neural damage. These new sequences may help in assessment of the different pathophysiologic conditions that occur in the diabetic foot. The physical basis of these techniques, their limitations, and their potential applications for diabetic foot assessment are detailed in this article. The introduction of advanced MR imaging multiparametric protocols, with the aim of enhancing the overall diagnostic accuracy of MR imaging, may help in treatment decision making and lead to improved patient outcomes. © RSNA, 2017.