Solitary pulmonary nodule: characterization with combined wash-in and washout features at dynamic multi-detector row CT.
OBJECTIVE
To prospectively assess the accuracy of combined wash-in and washout characteristics at dynamic contrast material-enhanced multi-detector row computed tomography (CT) in distinguishing benign from malignant solitary pulmonary nodules.


METHODS
Institutional review board approval and informed consent were obtained. The study included 107 patients (62 men, 45 women; mean age, 55 years; range, 22-81 years) with a solitary pulmonary nodule. After unenhanced CT (2.5-mm collimation) scans were obtained, dynamic CT was performed by using a helical technique (series of images obtained throughout the nodule, with 2.5-mm collimation, at 30, 60, 90, and 120 seconds and 4, 5, 9, 12, and 15 minutes) after intravenous injection of contrast medium (120 mL). Tissue diagnosis was made in 70 nodules, and follow-up images showed benignancy in the remaining 37 (no change in size, n = 32; decrease in size, n = 5). CT findings were analyzed in terms of wash-in and washout of contrast medium. Sensitivity, specificity, and accuracy for malignant nodules were calculated by considering both the wash-in and washout characteristics at dynamic CT.


RESULTS
There were 49 malignant and 58 benign nodules. When diagnostic criteria for malignancy of both wash-in of 25 HU or greater and washout of 5-31 HU were applied, sensitivity, specificity, and accuracy for malignancy were 94% (46 of 49 nodules), 90% (52 of 58 nodules), and 92% (98 of 107 nodules), respectively. Of 58 benign nodules, 27 showed less than 25 HU wash-in, 14 showed persistent contrast enhancement without washout and with wash-in of 25 HU or greater, and 11 showed washout greater than 31 HU and wash-in of 25 HU or greater.


CONCLUSIONS
Evaluation of solitary pulmonary nodules by analyzing combined wash-in and washout characteristics at dynamic contrast-enhanced multi-detector row CT showed 92% accuracy for distinguishing benign nodules from malignant nodules.
Jeong
Yeon Joo
YJ
Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Kangnam-Ku, Seoul 135-710, Korea.
Lee
Kyung Soo
KS
Jeong
Sun Young
SY
Chung
Myung Jin
MJ
Shim
Sung Shine
SS
Kim
Hojoong
H
Kwon
O Jung
OJ
Kim
Seonwoo
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D007479:Iopamidol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D016015:Logistic Models; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011829:Radiation Dosage; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging*; D018709:Statistics, Nonparametric; D036542:Tomography, Spiral Computed
D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol