Magnetic resonance diffusion-weighted imaging: extraneurological applications.

摘要: Diffsion–weighted (Dw) imaging has for a number of years been diagnostic tool in the field neuroradiology, yet only since end 1990s, with introduction echoplanar (EPI) and use sequences capable performing diffusion studies during single breath hold, it found applications at level abdomen. The inherent sensitivity to motion magnetic susceptibility Dw nonetheless still create problems study abdomen due artefacts caused by heartbeat intestinal peristalsis, as well presence various parenchymal–gas interfaces. With regard focal liver lesions, review literature reveals that is able differentiate lesions high water content (cysts angiomas) from solid lesions. latter, although there are differences between benign forms [focal nodular hyperplasia (FNH), adenoma] malignant [metastasis, hepatocellular carcinoma (HCC)] their apparent coefficient (ADC) average values histological type, significant overlap when assessed individually, consequent problem correct identification. One promising aspect possibility quantifying degree fibrosis patients chronic disease cirrhosis given deposit collagen fibres “restricts” molecules therefore reduces ADC values. However, even this field, can be considered preliminary far real clinical applications. retroperitoneum less affected similarly deserves attention imaging. Here possible mucin–producing tumours pancreas pseudocystic on basis though limited spatial resolution does not enable identification small may applied kidney hydronephrosis pyonephrosis tumours, forms. In addition, renal parenchyma significantly variable anatomic section physiological conditions, assessing functional alterations currently being studied. Indeed, good correlation glomerular filtration rate. musculoskeletal applications, absence regions studied enabled development sensitive greater than EPI. Attempts have made characterization soft–tissue findings so disputed. Greater agreement regarding technique response these chemotherapy: tumour necrosis thought increase whereas persistence vital neoplastic tissue tends lower it. most without doubt assessment vertebral collapse where shown associated an osteoporotic cause low cause. Nonetheless, here, moderate two types encountered. also used bone marrow cellularity: areas tightly packed cells show higher value hypocellular areas. particular, no difference noted normal hypercellular secondary lymphomatous infiltration hypocellular, normocellular haematopoietic marrow. joints, structure dimensions, particularly cartilage, creates technical difficulties related adequate signal–to–noise ratio, solved further technological developments. Lastly, degenerative inflammatory effusion found, fact explained result activity hyaluronidase present forms, which causes reduction concentration hyaluronic acid decrease viscosity.