Diffusion-weighted imaging of the musculoskeletal system in humans

Abstract

This article reviews the principles of diffusion-weighted imaging (DWI) and recent results in DWI of the musculoskeletal system. The potential of DWI in the diagnosis of pathology of the musculoskeletal system is discussed. DWI is a relatively new MR imaging technique that has already been established in neuroradiology, especially in the early detection of brain ischemia. The random motion of water protons on a molecular basis can be measured with DWI. To date DWI of the abdomen and of the musculoskeletal system has only been employed in scientific studies, but first results indicate that it may also be beneficial in these fields. Different diffusion characteristics have been found in normal tissues such as muscle, fat and bone marrow. Also, pathologic entities such as neoplasms, post-therapeutic soft tissue changes and inflammatory processes can be differentiated. Normal muscle shows significantly higher diffusion values than subcutaneous fat and bone marrow, due to a higher mobility of water protons within muscle. Soft tissue tumors exhibit a significantly lower diffusion value compared with post-therapeutic soft tissue changes and inflammatory processes. Necrotic tumor tissue can be distinguished from viable tumor due to significantly higher diffusion of water protons within necrotic tissue.

Characterization of chondroblastic osteosarcoma: Gadolinium‐enhanced versus diffusion‐weighted MR imaging

“…Commonly, malignant tumors demonstrate nuclear contour deformation, enlarged nuclei, and hyperchromatism, while also showing a high cellularity. As a result, the extracellular diffusion space of water molecules reduces and the ADC value of malignant tumors decreases (12,19,23). Moreover, it was demonstrated that the property of the extracellular matrix contributed to diffusion restrictions in these tumors (12).…”

“…The most important component of signal attenuation on DWI in tumor tissues is the diffusion of water molecules in the extracellular spaces (12). Commonly, malignant tumors demonstrate nuclear contour deformation, enlarged nuclei, and hyperchromatism, while also showing a high cellularity.…”

“…The signal intensity of DWI and the ADC values of the tissue change corresponding to the microstructure characteristics and physiological state of the tissues; these signal intensities have been used in various organs, including musculoskeletal tumors, and many studies have demonstrated the potential for providing information that can contribute to the differentiation between benign and malignant tumors (12)(13)(14)(15)(16). The most important component of signal attenuation on DWI in tumor tissues is the diffusion of water molecules in the extracellular spaces (12).…”

“…Diffusion-weighted MR imaging (DWI) is another method of assessing the functional properties of pathologic tissues and is useful for differentiation between benign and malignant tumors in various fields (8 -11), including the musculoskeletal system (12)(13)(14)(15)(16). DWI permits the quantitative assessment of water diffusion in tissues and therefore is used to measure the apparent diffusion coefficient (ADC), which reflects the mobility of water molecules in the tissues.…”

Magnetic resonance imaging of bone marrow in oncology, Part 1

“…Diffusion-weighted imaging (DWI) can quantitatively assess the mobility of water molecules by allowing calculation of the apparent diffusion coefficient (ADC) [22]. Extracellular motion of free water is the main contributor to the ADC and signal loss in tissues [23,24].…”