Solitary pulmonary nodules: dynamic contrast-enhanced MR imaging--perfusion differences in malignant and benign lesions.
OBJECTIVE
To determine whether dynamic contrast material-enhanced magnetic resonance (MR) imaging with use of kinetic and morphologic parameters reveals statistically significant differences between malignant and benign solitary pulmonary nodules.


METHODS
Fifty-eight patients met the inclusion criteria of a solitary 5-40-mm pulmonary nodule without calcification or fat at computed tomography. Fifty-one patients were examined successfully; 46 received a histologic diagnosis, and five received a diagnosis by means of observation over 2 years. Dynamic MR images were acquired every 10 seconds for a total of 4 minutes. Diagnostic characteristics for differentiation were examined by using threshold values for maximum peak enhancement, slope of enhancement, and washout. Receiver operating characteristic curves were calculated to test the usefulness of these parameters. The diagnostic performance of a combination of curve profiles and morphologic contrast material distribution were tested by using a decision tree.


RESULTS
Frequency of malignancy was 53% (27 of 51 nodules). Malignant nodules showed stronger enhancement with a higher maximum peak and a faster slope (P <.001). Significant washout (>0.1% increase in signal intensity per second) was found only in malignant lesions (14 of 27 lesions). Sensitivity, specificity, and accuracy were 96%, 88%, and 92%, respectively, for maximum peak; 96%, 75%, and 86% for slope; and 52%, 100%, and 75% for washout. When curve profiles and morphologic enhancement patterns were combined, sensitivity increased to 100%.


CONCLUSIONS
Dynamic MR imaging delineates significant kinetic and morphologic differences in vascularity and perfusion between malignant and benign solitary pulmonary nodules. Washout seems to be highly specific for malignancy.
Schaefer
Juergen F
JF
Department of Diagnostic Radiology, Eberhard-Karls-University Tübingen, Hoppe-Seyler-Str 3, 72076 Tübingen, Germany. juergen.schaefer@med.uni-tuebingen.de
Vollmar
Joachim
J
Schick
Fritz
F
Vonthein
Reinhard
R
Seemann
Marcus D
MD
Aebert
Herrmann
H
Dierkesmann
Rainer
R
Friedel
Godehard
G
Claussen
Claus D
CD
D000328:Adult; D000368:Aged; D002276:Carcinoid Tumor / Q000175:diagnosis / Q000473:pathology; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis / Q000473:pathology; D018288:Carcinoma, Small Cell / Q000175:diagnosis / Q000473:pathology; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics; D003663:Decision Trees; D003937:Diagnosis, Differential; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008168:Lung / Q000473:pathology; D008171:Lung Diseases / Q000175:diagnosis*; D008175:Lung Neoplasms / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012372:ROC Curve; D012189:Retrospective Studies; D003074:Solitary Pulmonary Nodule / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary; D014057:Tomography, X-Ray Computed
D003287:Contrast Media; D019786:Gadolinium DTPA