By Maruti Kumaran, MD, MBBS, FRCR
Computed tomography (CT) lung-imaging technology has evolved tremendously over the decades since its advent in 1967. Development of faster helical scanners with high resolution has made sub-second scanning possible. This enables us to obtain high-quality images and re-create movement throughout the lungs in dynamic imaging, while sometimes reducing the radiation dose received by the patient. Fast scanning also allows us to obtain imaging scans without patients having to hold their breath for long durations. Modern scanners allow us to view thin slices across lung tissue to pinpoint and examine any issues with greater accuracy.
These advances are now helping us make strides in the early diagnosis of lung cancer. At present, there is no cure and little effective treatment for lung cancer once it reaches a symptomatic stage; catching cancerous lung nodules with imaging screens while they are still small and asymptomatic is our only method for improving survival of the disease. Screening with low-dose CT is currently the most effective tool available for detecting very small, early-stage lung nodules in high-risk patients. These can then be biopsied using needle, bronchoscopic, surgical, or other techniques. Computer-aided CT helps automate nodule detection as well as allowing for volumetric quantification of nodules, thus helping the care team determine diagnostic and treatment course.
CT scans are also useful in the biopsy process; CT-guided needle biopsy remains the most diagnostically efficient biopsy method for lung nodules, with a diagnostic accuracy of more than 90%1 for lung nodules smaller than 2 cm. Automated lung segmentation based on CT scans (see image above) can also help surgeons localize nodules that are to be removed.
CT is on the front lines of lung cancer diagnosis and treatment; an experienced radiology team with cutting-edge equipment can be a valuable asset for improving detection and survival. ■
1 Ribeiro de Andrade, J., et al. 2018. CT-guided percutaneous core needle biopsy of pulmonary nodules smaller than 2 cm: technical aspects and factors influencing accuracy. J Bras Pneumol. 44(4): 307–314. DOI 10.1590/S1806-37562017000000259