Usefulness of the calculated apparent diffusion coefficient value in the differential diagnosis of retroperitoneal masses.
OBJECTIVE
To elucidate whether or not the apparent diffusion coefficient (ADC) values calculated from echo-planar diffusion-weighted (EPDW) MR images are useful in the differential diagnosis of retroperitoneal masses.


METHODS
In 50 patients with known retroperitoneal masses, EPDW images were performed with b-factors of 0-1100 seconds/mm2. The final histologic diagnoses of these lesions were as follows: 12 malignant lymphomas, four other malignant mesenchymal neoplasms, 25 malignant epithelial neoplasms, seven benign mesenchymal neoplasms, and two nonneoplastic lesions. The ADC values obtained for the solid portion of the lesions were used to represent each lesion, and the values of the histologic groups were compared.


RESULTS
The respective value of ADC for 12 malignant lymphomas, four other mesenchymal neoplasms, seven benign mesenchymal neoplasms, and two nonneoplastic lesions were as follows: 0.66 +/- 0.26, 1.26 +/- 0.50, 0.90 +/- 0.20, 1.87 +/- 0.48, 1.32 +/- 0.20 x 10(-3) mm2/second. The ADC value of the malignant lymphoma was significantly lower than that of the other malignant mesenchymal lesions, and was also lower than the ADC of the benign lesions. The ADC value of the malignant epithelial neoplasms was lower than that of the benign mesenchymal tumors. The ADC values of the malignant and benign lesions were 0.94 +/- 0.30 and 1.75 +/- 0.49 x 10(-3) mm2/second, respectively, which also demonstrated a significant difference.


CONCLUSIONS
ADC values calculated from EPDW MR images may provide useful information in the differential diagnosis of retroperitoneal masses.
Nakayama
Tomohiro
T
Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Yoshimitsu
Kengo
K
Irie
Hiroyuki
H
Aibe
Hitoshi
H
Tajima
Tsuyoshi
T
Shinozaki
Kenji
K
Nishie
Akihiro
A
Asayama
Yoshiki
Y
Kakihara
Daisuke
D
Matsuura
Shuji
S
Honda
Hiroshi
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012186:Retroperitoneal Neoplasms / Q000175:diagnosis*