Pulmonary Nodule Detection: Comparison of an Ultra Low Dose vs Standard Scan.

Detection of Pulmonary Nodules: Comparison of Ultra-low-dose Chest CT (Approaching a Two Views Chest X-ray Radiation) and Standard Low Dose CT. A Monocentric, Prospective, Non-randomized, Comparative, Open-label Study With Blind Reading of the Judgment Criteria.

Lung cancer screening programs are still discussed in Europe today, and one of the concern is radiation due to iterative CT. The aim of this monocentric, prospective, non randomized study is to compare an ultra low dose chest CT (approaching a two views X ray) versus a standard low dose chest CT for ≥4mm lung nodules detection, and secondary for lung nodule characterization and smoking associated findings (emphysema, bronchial abnormalities and coronary calcifications).

An additional Ultra Low Dose CT, approaching 0.2mSv, will be performed in consenting patients referred for non enhanced chest CT in our Revolution CT scanner (GE Healthcare®).The dose delivered with the two acquisitions is still lower than the french diagnostic reference level. Standard CT is interpreted and a report is sent to the referent physician as usual. Then the two acquisitions are read over time by two independent radiologists, blinded over judgment criterias. In case of discordance, an other radiologist will arbitrate. We hope to validate our Ultra low dose chest CT protocol, which is more than 10 times less radiating than a standard low dose CT, as a sensitive tool to detect lung nodules.

Inclusion criteria :

1. Patients referred for non enhanced chest CT for following indications :

   • lung nodule search or control
   • nodular abnormality on chest X ray
   • statement of COPD or emphysema
   • asbestos exposure
   • nodule localization before radio frequency ablation
   • assessment of disease extent of an extra thoracic cancer (in case of iodinated intravenous contrast agent contraindication)
   • statement before extrathoracic transplantation (in case of iodinated intravenous contrast agent contraindication)

2. Affiliated with the french social security

3. Who signed consent

Exclusion criteria :

1. Inability to lie down and still during the examination
2. Inability to hold breath more than 5 seconds
3. Pneumonia in the last 3 months
4. Body mass index more than 35kg/m²
5. exclusion period of another interventionnal study
6. referred for articles L1121-5 to L1121-8 of french public health code
7. Pregnant or breastfeeding women