David P. Naidich, MD

Currently, CT represents the best method for evaluating the entire spectrum of thoracic disease. With the introduction of multidetector CT scanners, including those with as many as 16 rows, the potential list of applications for use of CT to evaluate the chest continues to expand. Currently, topics of greatest interest include:

1. Lung Cancer Screening. While controversial, the ability of CT to detect tiny nodules as small as 5 - 8 mm represents a significant improvement over conventional image techniques, leaving open the possibility of early detection of lung cancer while still respectable. Based on preliminary non-randomized studies, the NCI has undertaken a massive randomized screening study - the National Lung Cancer Screening Trial (NLST), to include 50,000 individuals in each arm, the results of which should be available within the next several years.

2. Lung Nodule Characterization. On off-shoot of lung cancer screening initiatives, considerable interest has been directed towards methods for characterizing small lung nodules. This includes precise methods for determining subtle changes in nodule volume as well as the potential to perform contrast enhanced CT evaluation of nodule perfusions and permeability.

3. Computer Assisted Diagnosis (CAD). Also as a product of intense interest in lung cancer screening, considerable effort is now being directed towards the use of computers to identify and characterize small lung nodules otherwise potentially missed by radiologists. With the introduction of MDCT, we are now confronted with as many as 600 - 1,000 images/case. This increases the probability that small early lung cancers may be missed. Continued development in this field is leading toward use of CAD as a standard second read for all CT studies.

4. Pulmonary Embolism. The introduction of multidetector CT scanners over the past decade has revolutionized our approach to the diagnosis of pulmonary embolism. Using 4 and 16 detector CT scanners, we are now routinely able to scan the entire thorax using high resolution 1 - 1.25 mm sections. This enables us to obtain high quality contrast enhanced images of even 5th and 6th order pulmonary emboli, essentially obviating pulmonary angiography in nearly all cases.

5. CT guided bronchoscopy. With the recent introduction of ultrathin bronchoscopes it is now possible to directly access even small peripheral lung lesions. This has led to the development of virtual bronchoscopic methods for visualizing 8th - 10th order bronchi in order to provide bronchoscopists with an accurate roadmap, otherwise unobtainable using routine CT or fluoroscopic techniques.