Multi-detector Row CT
Multi-detector row CT represents a recent advance in helical CT technology. The Lightspeed CT (GE Medical Systems) mentioned earlier is currently capable of acquiring four channels of helical data simultaneously.
The advantages of multi-detector row CT for imaging the thorax include faster volumetric acquisitions, thin-section volumetric studies of large imaging volumes, retrospective reconstructions of thin sections from data used for routine thick-section imaging, and improved 3D rendering. Applications that may be substantially improved over singledetector row scanners include the following: (1) pulmonary CT angiography with improved detection of small isolated subsegmental emboli; (2) detection of fat or calcium within a pulmonary nodule that was detected on routine imaging; and (3) 3D imaging of the airways.
One significant price to be paid for these advances is the creation of huge image data sets involving hundreds of images, which will necessitate advances in the transfer, 3D display, and storage of these large volumes of CT image data. birth control pills online
Another recent advance in CT technology is that of real-time CT fluoroscopy. The most frequent application of CT fluoroscopy has been for real-time guidance during the biopsy of pulmonary nodules. Although conventional and helical CT have been used for this purpose for many years, lack of realtime visualization of target lesions has been an important limitation, especially for small lesions and in patients who are unable to cooperate with breath-holding.
When performing the biopsy of small nodules, the puncture of vital structures (eg, with lesions near the heart) can be avoided. Complex pleural drainages and catheter placements are facilitated particularly well, with an average procedural time-saving of 25 to 30 min. Another important use of CT fluoroscopy in the chest has been for the guidance of transbronchial biopsy via the fiberoptic bronchoscope. With this technique, CT fluoroscopy allows accurate trans-bronchial needle placement into enlarged lymph nodes or masses, with the avoidance of major vascular structures. Considerable attention, however, must be paid to reducing the relatively high radiation exposures involved in CT fluoroscopy.