Dynamic MR imaging: value of differentiating subtypes of peripheral small adenocarcinoma of the lung.
OBJECTIVE
To determine the utility of dynamic magnetic resonance imaging (MRI) in the differential subtyping of small adenocarcinomas of the lung.


METHODS
Twenty-nine pathologically diagnosed peripheral adenocarcinomas (less than 20 mm in diameter) underwent dynamic contrast-enhanced MRI. Maximum relative enhancement ratio, slope of enhancement, and corrected start time of enhancement were calculated from signal intensity-time curve of pulmonary lesion for each subject, and were statistically compared among bronchioloalveolar carcinoma (BAC) group (7 cases), mixed BAC group (10 cases), and adenocarcinoma group (12 cases).


RESULTS
Maximum relative enhancement ratio (P<0.001) and slope of enhancement (P<0.001) of BAC group were significantly higher than those of mixed BAC and adenocarcinoma groups. Start times of BAC group were significantly earlier than those of mixed BAC (P=0.0001) and adenocarcinoma groups (P<0.0001). Adapting the thresholds values of MR indexes from the positive tests, sensitivity, specificity, positive predictive value, negative predictive value and accuracy for differentiating BAC from other subtypes were 85.7, 100.0, 100.0, 95.7, and 96.6%, respectively.


CONCLUSIONS
Dynamic MRI is useful for differentiating subtypes of small peripheral adenocarcinoma.
Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan. yosirad@kobe-u.ac.jp <yosirad@kobe-u.ac.jp>
Yoshiharu
Y
Ohno
Hiroto
H
Hatabu
Daisuke
D
Takenaka
Hidemasa
H
Uematsu
Chiho
C
Ohbayashi
Takanori
T
Higashino
Munenobu
M
Nogami
Masahiro
M
Yoshimura
Masahiko
M
Fujii
Kazuro
K
Sugimura
D000230:Adenocarcinoma / Q000145:classification* / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000145:classification* / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged