Tracheobronchial Tree
Many methods have been used to evaluate airway obstruction. The most often used is conventional radiography. A recent study in pediatric patients demonstrated MR images in the sagittal and axial plane allowed clear demonstration of tracheal compression and narrowing secondary to a variety of etiologies. Correlation with endoscopy showed the appearance on MR corresponded closely to that observed at endoscopic observation. MR plays an important role in demonstrating airway obstruction in infants. MR allows delineation of the relationship of the airway to the major mediastinal blood vessels which may play a part in this airway obstruction.
Evaluation of diseases in the chest by MR is continually evolving. Early studies showed the potential of the technique for imaging the mediastinal and hilar structures and for demonstrating the normal anatomy of the thorax on sagittal, coronal, and transverse MR images. As more data have been compiled, investigators have compared MR to computed tomography for its ability to assess mediastinal and hilar adenopathy and masses, bronchogenic carcinoma and other pulmonary parenchyma lesions, and for assessment of the pulmonary vascularity. MR has been shown in these situations generally to provide equivalent information to that provided by computed tomography. tadanafil

MR, compared to computed tomography, is still in its infancy in regard to the length of time of its availability and in relation to the MR technology for obtaining images. MR is a technique that has wide variation as to type of image quality obtained depending upon the MR system utilized and the pulse sequence utilized. Because of the diverse nature of potential variables for imaging, many times the images are not equal in quality. As a consequence of this significant variability, the data in the literature are divergent on the precise utility of MR. Although the recommended use of MR may change rapidly, the current feeling is that MR should be used as a procedure complementary to computed tomography in those patients with allergy to iodinated contrast material and to aid in defining equivocal lesions as seen on computed tomography, such as small central hilar bronchogenic carcinomas.