Diffusion-weighted magnetic resonance imaging for diagnosing malignant pulmonary nodules/masses: comparison with positron emission tomography.
BACKGROUND
Recent developments of diffusion-weighted magnetic resonance imaging (DWI) make it possible to image malignant tumors to provide tissue contrast based on difference in the diffusion of water molecules among tissues, which can be measured by apparent diffusion coefficient (ADC) value. The aim of this study is to examine the usefulness of DWI for benign/malignant discrimination of pulmonary nodules/masses compared with F-fluorodeoxyglucose (FDG) positron emission tomography (PET).


METHODS
PET and DWI were carried out prospectively in 104 patients with 140 pulmonary nodules/masses before surgery. FDG uptake of each lesion was quantitatively measured by a contrast ratio of standard uptake value (SUV-CR) between the lesions and contralateral lung. Diffusion of water molecule in each lesion was quantitatively measured by a minimum ADC (ADC-min). The diagnostic results were compared between the two modalities.


RESULTS
The receiver operating characteristics curve showed cutoff values of the ADC-min and the SUV-CR for benign/malignant discrimination to be 1.1 x 10 mm/s and 0.37, respectively. DWI and PET showed sensitivities of 0.70 and 0.72 and specificities of 0.97 and 0.79, respectively. Although there was no significant difference in sensitivity between the two methods, DWI showed a significantly higher specificity than PET because of fewer false-positives for active inflammatory lesions (p = 0.03). The ADC-min and SUV-CR values showed a significant reverse correlation (r = -0.504, p < 0.001).


CONCLUSIONS
DWI may be able to be used in place of FDG-PET to distinguish malignant from benign pulmonary nodules/masses with fewer false-positive results compared with FDG-PET.
Mori
Takeshi
T
Department of Thoracic Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
Nomori
Hiroaki
H
Ikeda
Koei
K
Kawanaka
Koichi
K
Shiraishi
Shinya
S
Katahira
Kazuhiro
K
Yamashita
Yasuyuki
Y
D000230:Adenocarcinoma / Q000175:diagnosis; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018196:Carcinoma, Adenosquamous / Q000175:diagnosis; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis; D003952:Diagnostic Imaging; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000175:diagnosis*; D014057:Tomography, X-Ray Computed
D019788:Fluorodeoxyglucose F18