Der Radiologe
-
Current diagnostic tools for the assessment of lung function are limited by global measurements or the need for radioactive tracers. Ideally, these tools should allow quantitative, regional distinct analyses without exposure to radiation. The current paper presents oxygen-enhanced functional MRI for assessment of lung ventilation. ⋯ Lower signal-to-noise ratios can be overcome by changing the relaxation times. New navigator techniques allow further compensations. This article focuses on the presentation of low-field scanners and the application of T1 and T2(*) maps is described for healthy volunteers and first patients.
-
Since its first application in patients with acute lung injury 25 years ago, computed tomography (CT) has significantly influenced the understanding of the pathophysiology, diagnosis and management of acute lung injury and has become an important diagnostic modality for these patients. The aim of this article is to review important disease-specific aspects of CT acquisition and qualitative and quantitative analyses of CT data. Morphological changes seen on CT and associated functional alterations are discussed. Methods used for the quantification of lung aeration are described and their limitations outlined.
-
Lung function measurements are the domain of spirometry or plethysmography. These methods have proven their value in clinical practice, nevertheless, being global measurements the functional indices only describe the sum of all functional units of the lung. Impairment of only a single component of the respiratory pump or of a small part of lung parenchyma can be compensated by unaffected lung tissue. ⋯ Unfortunately, lung parenchyma is not easy to image using MRI due to its low signal intensity. For this reason first applications of MRI in lung function measurements concentrated on the movement of the thoracic wall and the diaphragm. Recent technical advances in MRI however might allow measurements of regional dynamics of the lungs.
-
Pulmonary diseases have a high health-related and economic significance. (3)He-MRI is an alternative imaging method which can detect ventilatory disturbances with a high sensitivity. The application of different pulse sequences allows static and dynamic assessment of ventilation and bronchial gas flow, non-invasive measurement of intrapulmonary oxygen partial pressure and quantification of pulmonary parenchyma destruction and overinflation. Generally, the method is applicable for obstructive and restrictive ventilatory disturbances but initial approaches also exist for vascular pulmonary diseases. Specific clinical applications remain to be determined but (3)He-MRI is an excellent instrument for the assessment of physiologic and pathophysiologic interrelations in the distribution of ventilation.