Project Details
Abstract
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
External Project ID:NSC101-2314-B182-067
Status | Finished |
---|---|
Effective start/end date | 01/08/12 → 31/07/13 |
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