Enhancement of thoracic masses using nonionic MR contrast agents.
OBJECTIVE
This study evaluated the effect of a new nonionic MR contrast medium, gadodiamide injection (Omniscan; Sanofi-Winthrop), on enhancement of thoracic masses on T1-weighted SE images.


METHODS
Gadodiamide injection was administered intravenously at a dose of 0.2 mmol/kg to 26 patients with thoracic masses. The T1-weighted images with and without fat suppression and T2-weighted images obtained before contrast medium injection were compared with T1-weighted images obtained at 5, 30, and 45 min and a T1-weighted fat-suppressed image at 10 min after administration of the contrast medium. Enhancement of the thoracic masses and image quality were quantified by measuring signal intensity, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) using muscle and fat as reference tissues.


RESULTS
The SNR of the masses increased significantly (p < 0.001) following contrast material injection both on standard T1-weighted sequences and on T1-weighted fat-suppressed images when compared with the precontrast T1-weighted images with and without fat suppression. The CNR (reference tissue muscle) improved significantly (p < 0.001) after contrast medium injection and persisted for 45 min on T1-weighted images compared with those prior to contrast medium. However, there was no significant difference in CNR between the T2-weighted images obtained before and the T1-weighted images obtained after contrast agent administration. On the other hand, the SNR of contrast-enhanced images was significantly better than that of the T2-weighted images. When fat was used as a reference tissue, CNR of the thoracic masses decreased significantly.


CONCLUSIONS
This study shows that gadodiamide injection caused significant enhancement of thoracic masses on T1-weighted images, which rendered high signal intensity to the masses similar to the appearance on T2-weighted images. In comparison with the T2-weighted images, SNR was significantly improved.
Kanth
N
N
Department of Radiology, University of California Medical School, San Francisco.
Dulce
M
M
O'Sullivan
M
M
Duerinckx
A
A
Gamsu
G
G
Caputo
G R
GR
Higgins
C B
CB
D000293:Adolescent; D000328:Adult; D000368:Aged; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008171:Lung Diseases / Q000473:pathology*; D008175:Lung Neoplasms / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds; D004369:Pentetic Acid / Q000031:analogs & derivatives*; D013896:Thoracic Diseases / Q000473:pathology*; D013899:Thoracic Neoplasms / Q000473:pathology
D003287:Contrast Media; D009942:Organometallic Compounds; D004369:Pentetic Acid; C064925:gadodiamide; D019786:Gadolinium DTPA