Coronary calcium scoring with an automated technique fits well in a lung cancer screening setting, enabling cardiovascular risk assessment in a population potentially at high risk of cardiac events, according to a Dutch study presented at the RSNA 2011 meeting.
In a study involving nearly 1,800 cases, a team from the University Medical Center Utrecht in the Netherlands found an automated scoring system could be a valuable tool in helping to assign patients to appropriate cardiovascular risk groups.
"Automatic coronary calcium scoring in a lung cancer screening program is feasible," said presenter Ivana Isgum, PhD. In the landmark Nederlands-Leuvens Longkanker Screenings Onderzoek (NELSON) lung cancer detection trial that involved nearly 16,000 participants, more heavy smokers were found to be affected by cardiovascular disease than by lung cancer.
Calcium scoring would seem a good fit with lung cancer screening, which utilizes low-dose, non-ECG-synchronized chest CT scans. Coronary calcium scores from such scans have been shown to be a predictor of cardiac events and mortality, she noted.
Performing manual calcium scoring in a lung cancer screening setting is very difficult, however, due to the large number of acquired images and the CT acquisition protocol; low-dose acquisition produces noise, and cardiac motion can make calcifications either blurry or hard to visualize, she said. The NELSON study also included a population of heavy smokers, with many calcifications per scan that would require a lot of user interaction.
The university built an automatic calcium scoring system, which first creates a coronary calcium scoring map that assigns probability to every location in the scan for the appearance of coronary calcifications. Thresholding is then performed to generate calcification candidates, and a machine learning system completes the process by identifying coronary calcification based on density and location, Isgum said.
To evaluate the performance of the scoring system in a lung cancer screening setting, the researchers selected 1,796 baseline chest CT scans from the NELSON trial.
The study included images from former heavy smokers who ranged in age from 50 to 75, with acquisition parameters of 16 x 0.75-mm collimation and tube current of 30 mAs. The low-dose, noncontrast chest CT images were reconstructed to 3.1-mm sections with 1.4-mm increments.
After automatic scoring was performed, one of four trained observers visually inspected the scans, and, if necessary, provided manual correction. Agatston and calcium volume scores were computed before and after manual correction.
Based on the Agatston score, each subject was then assigned to a cardiovascular risk group. The researchers also wanted to evaluate interobserver agreement for manual scoring, and selected a subset of 45 scans that were manually scored by two observers. This subset was equally divided over the cardiovascular risk groups.
Both methods yielded similar scoring results.
Automated versus manual calcium scoring
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Automatic coronary calcium scoring more frequently underestimated than overestimated the amount of calcification, Isgum noted.
Based on the volume score, Spearman's rank correlation (ρ) was calculated to assess correlation before and after manual correction of automated scores, and between observers for manual scoring. Linearly weighted kappa statistic (κ) was calculated to evaluate the agreement in cardiovascular risk category assignment.
The researchers found high correlation (ρ = 0.88) and an agreement κ of 0.79 between the automated and manual scores, while interobserver manual scoring had a correlation ρ of 0.89 and an agreement κ of 0.83.
"Agreement between automatic and manually corrected scores is similar to interobserver agreement," Isgum said.
![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnieeurope.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&fit=crop&h=100&q=70&w=100)
![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnieeurope.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&dpr=2&fit=crop&h=167&q=70&w=250)
