Table 2. Comparison of different CT values and sizes for stages of adenocarcinoma appearing as pure GGNs.
| CT value/size | Pre-invasive lesions | Invasive lesions | Pa | P1b | P2b | P3b | |||
|---|---|---|---|---|---|---|---|---|---|
| AAH (n=7) | AIS (n=12) | MIA (n=38) | IAC (n=50) | ||||||
| Mean CT value (HU) | −643.5±61 | −634.1±48 | −622.8±45 | −600.5±84 | 0.112 | 0.771 | 0.615 | 0.127 | |
| rCT value 1 (HU) | 227.6±49 | 231.5±62 | 282.8±46 | 315.5±71 | 0.000 | 0.894 | 0.013 | 0.015 | |
| rCT value 2 | 0.74±0.06 | 0.73±0.07 | 0.69±0.05 | 0.65±0.08 | 0.000 | 0.897 | 0.047 | 0.026 | |
| Mean size (cm) | 0.93±0.17 | 0.99±0.49 | 1.16±0.48 | 1.64±0.49 | 0.001 | 0.790 | 0.285 | 0.000 | |
| CT value of lung (HU) | −871.1±21 | −865.6±30 | −905.6±20 | −915.9±21 | 0.000 | 0.595 | 0.000 | 0.029 | |
Cases of nodules shown in brackets. P: P value for pre-invasive versus invasive tumors; P1: P value for AAH versus AIS; P2: P value for AIS versus MIA; P3: P value for MIA versus IAC. a, two-tailed Student t-test; b, Student-Newman-Keuls post-test. AAH, atypical adenomatous hyperplasia; AIS, adenocarcinoma in situ; GGN, ground-glass nodule; IAC, invasive adenocarcinoma; MIA, minimally invasive adenocarcinoma; rCT, relative CT value.