[Computer-aided detection of small pulmonary nodules in multidetector spiral computed tomography (MSCT) in children].
OBJECTIVE
Retrospective evaluation of computer-aided detection software (CAD) for automated detection (LungCAD, Siemens Medical solutions, Forchheim, Germany) and volumetry (LungCARE) of pulmonary nodules in dose-reduced pediatric MDCT.


METHODS
30 scans of 24 children (10.4+/-5.9 years, 13 girls, 11 boys, 39.7+/-29.3 kg body weight) were performed on a 16-MDCT for tumor staging (n=18), inflammation (n=9), other indications (n=3). Tube voltage 120 kVp and effective mAs were adapted to body weight. Slice thickness 2 mm, increment 1 mm. A pediatric radiologist (U1), a CAD expert (U2) and an inexperienced radiologist (U3) independently analyzed the lung window images without and with the CAD as a second reader. In a consensus decision U 1 and U 2 were the reference standard.


RESULTS
Five examinations had to be excluded from the study due to other underlying lung disease. A total of 24 pulmonary nodules were found in all data sets with a minimal diameter of 0.35 mm to 3.81 mm (mean 1.7+/-0.85 mm). The sensitivities were as follows: U1 95.8% and 100% with CAD; U2 91.7% U3 66.7%. U2 and U3 did not detect further nodules with CAD. The sensitivity of CAD alone was 41.7 % with 0.32 false-positive findings per examination. Interobserver agreement between U1 / U2 regarding nodule detection with CAD was good (k=0.6500) and without CAD very good (k=0.8727). For the rest (U1 /U3; U2 / U3 with and without CAD), it was weak (k=0.0667-0.1884). Depending on the measured value (axial measurement, volume), there is a significant correlation (p=0.0026-0.0432) between nodule size and CAD detection. Undetected pulmonary nodules (mean 1.35 mm; range 0.35-2.61 mm) were smaller than the detected ones (mean 2.19 mm; range 1.35-3.81 mm). No significant correlation was found between CAD findings and patient age (p=0.9263) and body weight (p=0.9271) as well as nodule location (subpleural, intraparenchymal; p=1.0) and noise/SNR.


CONCLUSIONS
In our study with 2 mm slice thickness and very small lesion sizes, the analyzed CAD algorithm for detection and volumetry of pulmonary nodules has limited application in pediatric dose-reduced 16-MDCTs. Determination of lesion size is possible even in the case of false-negatives.
Honnef
D
D
Radiologische Diagnostik, Universitätsklinikum RWTH Aachen, Aachen. honnef@rad.rwth-aachen.de
Behrendt
F F
FF
Bakai
A
A
Hohl
C
C
Mahnken
A H
AH
Mertens
R
R
Stanzel
S
S
Günther
R W
RW
Das
M
M
D000293:Adolescent; D000465:Algorithms; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media / Q000008:administration & dosage; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007223:Infant; D007472:Iohexol / Q000031:analogs & derivatives; D008168:Lung / Q000000981:diagnostic imaging; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D015588:Observer Variation; D012680:Sensitivity and Specificity; D012985:Software Design; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging*; D036542:Tomography, Spiral Computed / Q000379:methods*
D003287:Contrast Media; D007472:Iohexol; C038192:iopromide