Dr. Gotway is an Assistant Professor of Radiology at the University of California, San Francisco and Chief of Thoracic Imaging at San Francisco General Hospital, San Francisco, CA.

The technological aspects of radiology have been increasing rapidly in recent years. With the advent of helical CT a decade ago, it became possible to acquire image datasets in a single breath hold, thus eliminating misregistration artifacts. The ability to acquire an entire volume of tissue made three-dimensional imaging a possibility, and the sophistication and utility of such techniques have proliferated tremendously as a result. Additionally, as CT became faster, it became possible to coordinate the scan acquisition parameters with the administration of the intravenous contrast bolus, making noninvasive vascular imaging with CT a reality.

Advances in CT technology have again taken a giant leap forward with the introduction of multidetector-row helical CT technology. Four channel multidetector-row helical CT scanners provide nearly three times the volume coverage as single-detector systems, without compromising image quality. In fact, the quality of imaging, including multiplanar and volumetric reconstructions, is likely to be superior with multidetector systems compared with single-detector scanners. However, this new technology comes with a price. Radiologists must increase their familiarity with the technical aspects of helical CT acquisitions to realize the promise of improved image quality with these new systems. This is particularly true of vascular applications, such as the imaging of aortic diseases or pulmonary embolism. In this issue, we will address the helical CT evaluation of aortic diseases, with special emphasis on the scan acquisition parameters and some of the pitfalls that result from the techniques applied in this clinical setting.

Just as radiologic technology has advanced in recent years, so has the ability of the pathologist to provide increasingly precise tissue characterization. Advances in histopathologic techniques has lead to a fundamental re-thinking of many diseases; nowhere is this more true than in the field of interstitial lung diseases. The original classification of interstitial diseases has been modified recently, and, just as many are beginning to catch up, the names may be changing again! Fortunately, the imaging manifestations may be slightly more durable. Thus, in addition to aortic imaging with helical CT, in this issue we also revisit the imaging of diffuse lung diseases, with special emphasis on interstitial pneumonias. The imaging of diffuse lung diseases is an extensive and complex topic and cannot be addressed adequately in a single review article. However, many excellent references are provided, and I hope both of these articles stimulate interest and provide a foundation for further reading.