The localization of incidental findings was as follows (Fig.1 and Fig.2):
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lungs and bronchi - 68.5%,
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pleura - 2.75%,
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cardiovascular system - 76.4%,
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mediastinum - 2.75%,
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abdominal cavity (upper abdomen) and retroperitoneal space - 4.2%,
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organs of the endocrine system - 2.7%,
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mammary glands - 0.8%.
A total of 58.4% of incidental findings were not reported in the original protocols of the ultra-LDCT studies.
In the initial ultra-LDCT report, radiologists would often mention adrenal lesions (3 cases, not indicated 100.0%), pulmonary trunk dilatation (19 - 100.0%), ascending and descending aorta dilatation (159 - 82.3% ), as well as the presence of coronary calcium (64 - 33.0%).
Fig. 2: Distribution of incidental finding's in Moscow Lung Cancer Screening
Lungs and bronchi:
In total, incidental findings of the respiratory system were detected in 68.5% (174/254) cases. In the primary ultra-LDCT protocols, only 42.5% (74/174) of them were reported.
The most common incidental findings from the respiratory system:
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thickening of the bronchial wall - 51.1% (89/174),
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emphysema - 31.65% (55/174),
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bronchiectasis - 51.1% (89/174),
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interstitial changes in the parenchyma - 16.4% (29/174),
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consolidation of the parenchyma - 6.1% (11/174),
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fibrotic changes - 22.3% (39/174),
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calcifications - 9.8% (17/174).
Pleura and pleural cavity
In total, incidental findings of the pleura and pleural cavity were detected in 2.72% (7/254) cases. Only 43.0% (3) of them were indicated initially.
The most common incidental findings of pleura and pleural cavity were:
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pleural effusion - 28.5% (2),
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pleural plaques - 14.2% (1),
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round atelectasis - 14.2% (1),
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intrapulmonary lymph nodes - 14.2% (1),
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primary pleural tumor - 28.5% (2).
Cardiovascular system
In total, incidental findings of the cardiovascular system were detected in 76.4% (169/221) cases. Initially, 66.8% (113) of them were reported with no recommendations (for example, consultation by a cardiologist) given.
The distribution of cardiovascular incidental findings is shown in Fig. 3. The most common (69.6%; 154/221) finding was calcification of the coronary arteries.
Fig. 3: The structure of incidental findings in cardiovascular system detected during lung cancer screening by ultra-LDCT
Pathological changes in the mediastinum
In total, incidental findings in the mediastinum were detected in 2.75% (7/254) cases. Primary protocols indicate 71.0% (5) of them (Fig. 4).
The most common incidental findings in the mediastinum were:
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lymph node enlargement - 57.1% (4),
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esophageal pathology - 28.5% (2),
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mass lesions of the mediastinum - 14.3% (1).
Pathological changes in upper abdomen.
In total, incidental findings of the abdomen were detected in 4.1% (10) cases. Only 30.0% (3) of them were indicated in the primary ultra-LDCT protocols with no management recommendations given.
The most frequent incidental findings in epigastric and subphrenic areas were:
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liver pathology - 20% (2),
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kidney pathology - 30% (3),
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adrenal gland lesions - 30% (3)
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diaphragmatic hernia - 20% (2).
Fig. 4: The structure of other incidental findings (IF) during lung cancer screening by ultra-LDCT.
Endocrine system
In total, incidental findings of endocrine system organs were detected in 3.2% (8/254) cases. In the primary ultra-LDCT protocols, these findings are not indicated at all.
The most frequent incidental findings in 8 identified individuals were:
Mammary glands
In the mammary glands, incidental findings were found in 0.8% (2/254) of cases. These findings were also omitted in the primary ultra-LDCT protocols.