The Role of 640-Slice Spiral Low-Dose Ct and Ekg-Gated Volume Scans in the Simultaneous Assessment of Coronary Artery Calcification and Lung Nodule

Project: National Science and Technology CouncilNational Science and Technology Council Academic Grants

Project Details


On June 15, 2011, the National Health Bureau officially announced that cancer and coronary artery disease (CAD) were the two most common causes of 144,709 deaths in Taiwan in 2010. Of the total number of deaths, cancer constituted 28.4% (41,046 deaths) and CAD comprised 10.8% (15,628 deaths). Lung cancer was the most common cause of mortalities among neoplasms, which comprised 20% of malignancies. These findings are similar to those seen in USA. Both smoking and age are risk factors of lung cancer and CAD. Thus, early detection and treatment of lung cancer and CAD remains a critical issue. Lung low dose CT (LDCT) is an important diagnostic tool for early detection of lung cancer. Coronary artery calcification (CAC) is the surrogate marker of CAD, where the higher the calcium score, the greater the probability of a patient having CAD. Thus, using non-enhanced chest CT in acceptable radiation doses to assess lung nodules and CAD may benefit those with risk factors for lung cancer and CAD. Previous studies on CAC measurement by LDCT images were limited to retrospective, subjective, and qualitative analyses. Furthermore, these reports did not detail important parameters of reconstructed images, including filter kernel, field of view (FOV) and pixel resolution. Only two articles had prospectively assessed the reliability of CAC measurements from LDCT images while using the EKG-gated cardiac CT as a gold standard, although EKG-gated chest CT scans were not reported. Thus, these un-gated spiral LDCT images may not be reliable in assessing CAC, as they are associated with inter-technique variability from cardiac motion artifacts and inconsistent reconstruction parameters. In this three year project, a prospective and quantitative study will be conducted in 300 subjects (240 males and 60 females, ages 45 to 80 years old) with risk factors of CAD or lung cancer. Three CT techniques will be used, including an un-gated spiral LDCT (scan mode I, FOV 32 cm, two filter kernel FC02 and FC08 will be applied), an EKG-gated chest volume CT (scan mode II, FOV 32 cm, filter kernel FC 12) to assess lung and CAC, and a regular EKG-gated cardiac volume CT (scan mode III, FOV 22 cm, filter kernel 12) to be used as the golden standard for assessing CAC. In addition to the assessment of lung nodules and CAC by sourced images of both scan modes I and II, the cardiac images (FOV 22 cm, contiguous 3 mm slice thickness) reconstructed by the raw data of those two scan modes will also be assessed for 2 calcium scoring by computer soft ware. In this project, the innovative scan mode II or EKG-gated chest volume CT scan will be used to reduce motion artifact caused by physiological cardiac motion. Such scanning techniques may be more accurate in assessing CAC. This project will follow the principle of ALARA (as low as reasonably achievable), and the total effective radiation dose of CT will be less than 10 mSv for each subject. This is equivalent to an abdominal CT dosage as suggested by the Atomic Energy Council of Taiwan. By monitoring the scanning and reconstruction parameters (e.g. filter kernel, slice thickness, pixel spatial resolution, kVp, mA), the purposes of this project is to first, assess if calcium scores measured from sourced images of scan modes I (FOV 32 cm) and II (FOV 32 cm) are consistent with those obtained from scan mode III (FOV 22 cm). Second, to assess the reliability of calcium scoring measured from the reconstructed cardiac images (FOV 22 cm) by raw data of scan modes I and II. Third, to assess the accuracy of scan mode II in delineating lung nodules based on scan mode I. Fourth, the final goal of this project is to validate scan mode II or EKG-gated chest volume CT in assessing lung nodules and CAC. Such an innovative scanning technique may be helpful in screening lung cancer or CAD in the future.

Project IDs

Project ID:PC10108-0913
External Project ID:NSC101-2314-B182-067
Effective start/end date01/08/1231/07/13


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