Magnetic Resonance for Evaluation of the Thorax: CT
Unlike other imaging modalities that depend on information from one parameter, such as CT which is dependent on electron density, an advantage of MR is that it derives information from multiple parameters, such as hydrogen density, T1 and T2 relaxation times, and bulk proton motion. Different imaging sequences demonstrate the effect of one or a combination of these parameters allowing for superb display of the differences between normal and abnormal tissues. MR has improved our ability to detect characteristics of abnormal tissues more so than any other imaging technique. In some circumstances, MR allows improved specificity for diagnosis. Some of the disadvantages of MR include: a slower scanning time resulting in image degradation due to patient motion; the possibility of patient claustrophobia; the contraindication to imaging patients with pacemakers or intracranial aneurysm clips; and the limitation of the technique to hemody-namically stable patients as there are limited monitoring capabilities currently available for MR imaging.
Magnetic resonance has very rapidly become an important tool for a variety of conditions presenting within the thorax. canadian-familypharmacy.com
MR offers many advantages for imaging of the thorax, including: superior soft tissue contrast resolution when compared to computed tomography, and accurate delineation of the blood vessels and tracheobronchial tree without the need for contrast media. It is well known that difficulty occasionally arises with computed tomography at the level of the thoracic inlet because streak artifacts secondary to bony structures may obscure lesions. MR is particularly well suited for evaluation of this region because of the capability of multiplanar imaging and the superb delineation of vascularity. This review will discuss the MR techniques for imaging of the thorax and several current indications for imaging of the thoracic inlet, mediastinum, hila, lung parenchyma, pulmonary vascularity, and the tracheobronchial tree.