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P2.19 - Poster Session 2 - Imaging (ID 180)
- Event: WCLC 2013
- Type: Poster Session
- Track: Imaging, Staging & Screening
- Presentations: 1
- Coordinates: 10/29/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
P2.19-004 - Characterization of solitary pulmonary lesions combining visual perfusion and quantitative diffusion MR imaging (ID 1000)
09:30 - 16:30 | Author(s): K. Nackaerts
To evaluate the diagnostic accuracy of dynamic contrast enhanced (DCE)magnetic resonance (MR) and diffusion weighted imaging (DWI) sequences for defining benign or malignant character of solitary pulmonary lesion (SPL) in a preoperative setting.
This study was approved by the local ethics committee; all patients provided written informed consent. First, 54 consecutive patients with SPL, clinically staged (CT and PET or integrated PET-CT) as N0M0, were included in this prospective study. An additional MR examination including DCE and DWI was performed one day before the surgical procedure. Histopathology of the surgical specimen served as standard of reference. Subsequently, this functional method for SPL characterization was validated with a second cohort of 54 patients.
In the feasibility group, 11 benign and 43 malignant SPL were included with a maximal diameter that varied from 3 to 71 mm (mean 23.2 mm). Using the conventional MR sequences with visual interpretation of DCE-MR curves sensitivity, specificity, accuracy were respectively 100%, 55% and 91%. By additional interpretation of quantitative apparent diffusion coefficient (ADC) values (with a cutoff value of 1.52x10-3 mm2/sec for ADC calculated from high b-values (ADChigh) these results improved to 98%, 82% and 94% respectively. In the validation group, with 14 benign and 40 malignant SPL (diameter ranged between 7 mm and 10 cm - mean 26.5 mm), these results were confirmed with a sensitivity, specificity and accuracy of 95%, 79%, and 91%, respectively.
Visual DCE-MR-based curve interpretation can be used for initial differentiation of benign from malignant SPL, while additional quantitative DWI-based interpretation can further improve the specificity.
PL03 - Presidential Symposium Including Top Rated Abstracts (ID 85)
- Event: WCLC 2013
- Type: Plenary Session
- Presentations: 1
PL03.01 - Lung cancer probability in subjects with CT-detected pulmonary nodules (ID 1578)
08:15 - 09:45 | Author(s): K. Nackaerts
The main challenge in computed tomography (CT) screening for lung cancer is the high prevalence of pulmonary nodules and the relatively low incidence of lung cancer. Thresholds for nodule size and growth rate, which determine which nodules require additional diagnostic procedures, should be based on the lung cancer probability of the individual.
Diameter, volume and volume-doubling time (VDT) of 9,681 non-calcified nodules detected by CT screening in 7,155 subjects were used to quantify lung cancer probability. Complete coverage on all lung cancer diagnoses was obtained by linkages with the national cancer registry. The nodule management algorithm recommended by the ACCP was evaluated and an improved algorithm, based on lung cancer probability, was proposed.
Lung cancer probability was low in subjects with a nodule volume <100mm³ (≤0.7%) or maximum transverse diameter <5mm (≤0.6%) Moreover, probability in these subjects was not significantly different from that in subjects without nodules (0.4%). Lung cancer probability was 0.9-5.8% for nodules with a volume 100-300mm³ or a diameter 5-10mm; the VDT further stratified the probability: 0.0-0.9% for VDTs>600days, 4.0% for VDTs 400-600days and 6.7-25.0% for VDTs<400days. Lung cancer probability was high for participants with nodule volumes ≥300mm³ (8.9-26.1%) or diameters ≥10mm (11.1-26.2%), even with long VDTs. Finally, raising the thresholds for nodule size recommended by the ACCP for an indeterminate result from 4mm to 5mm and for a positive result from 8mm to 10mm, would yield fewer follow-up CT examinations (from 29.8% to 22.2%) and fewer additional diagnostic procedures (from 8.9% to 5.3%) while maintaining the sensitivity at 94.2%.
Small nodules (volume <100mm³ or diameter <5mm) are not predictive for lung cancer. Immediate diagnostic evaluation is necessary for subjects with large nodules (volume ≥300mm³ or diameter ≥10mm) and only for subjects with nodules of intermediate size is VDT assessment advocated.
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