Evaluation of lung cancer by enhanced dual-energy CT: association between three-dimensional iodine concentration and tumour differentiation.
OBJECTIVE
To investigate the correlation between iodine concentration of dual-energy CT (DECT) and histopathology of surgically resected primary lung cancers.


METHODS
We reviewed the medical records, post-operative pathological records and pre-operative DECT images of patients who underwent surgical lung resection for primary lung cancer. After injection of iodinated contrast media, arterial and delayed phases were scanned using 140- and 80-kV tube voltages. Three-dimensional iodine concentration (iodine volume) of primary tumours was calculated using lung nodule application software.


RESULTS
A total of 60 patients (37 males and 23 females; age range, 39-84 years; mean age, 69 years) with 62 lung cancers were analysed. The resected tumours were histopathologically classified into well-differentiated (G1; n = 20), moderately differentiated (G2; n = 29), poorly differentiated (G3; n = 9) and undifferentiated (G4; n = 4) groups by degree of tumour differentiation (DTD). The mean ± standard deviation of iodine volume at the delayed phase was 59.6 ± 18.6 HU in G1 tumours, 46.5 ± 11.3 HU in G2 tumours, 34.3 ± 15.0 HU in G3 tumours and 28.8 ± 6.4 HU in G4 tumours; significant differences were observed between groups (p < 0.001). Univariate logistic regression analysis showed that iodine volumes both at the early and delayed phases were significantly correlated with DTD (p = 0.006 and p = 0.001, respectively), whereas gender, body weight and tumour size were not (p = 0.084, p = 0.062 and p = 0.391, respectively).


CONCLUSIONS
The iodine volume of lung cancers was significantly associated with their DTD. High-grade tumours tended to have lower iodine volumes than low-grade tumours.


CONCLUSIONS
Iodine volume measured by DECT could be a valuable functional imaging method to estimate differentiation of primary lung cancer.
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Shingo
http://orcid.org/0000-0002-3256-0390
S
Iwano
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Rintaro
R
Ito
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Hiroyasu
H
Umakoshi
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Shinji
S
Ito
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Shinji
S
Naganawa
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007472:Iohexol / Q000031:analogs & derivatives; D007479:Iopamidol; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014283:Triiodobenzoic Acids
D003287:Contrast Media; D014283:Triiodobenzoic Acids; D007472:Iohexol; C038192:iopromide; D007479:Iopamidol; C054871:ioversol