Whole-body MRI with assessment of hepatic and extraabdominal enhancement after administration of gadoxetic acid for staging of rectal carcinoma.
BACKGROUND
In TNM staging of rectal cancer by MRI, unspecific extracellular contrast agent Gd-DTPA is established for extrahepatic and vascular enhancement whereas liver-specific gadoxetic acid has proven high accurate detection of liver metastasis.


OBJECTIVE
To compare intraindividually the qualification and quantification of enhancement in liver parenchyma, abdominal, pulmonary, and pelvic vessels between gadoxetic acid and Gd-DTPA.


METHODS
Sixteen patients with histologically proven rectal carcinoma (mean age 62.9 years) were imaged twice by MRI. For pretherapeutic staging 10 mL gadoxetic acid (mean dose 0.032 mmol Gd/kg body weight) and for restaging after neoadjuvant therapy Gd-DTPA (0.1 mmol Gd/kg body weight) were administered. The liver was acquired in arterial-dominant and portal venous phases, the thorax and pelvis were depicted in venous phases using three-dimensional T1-weighted sequences. Contrast enhancement was rated by two independent readers and compared by means of multinomial regression analysis using generalized estimating equations. Signal-to-noise ratios were compared by two-sided paired t-tests.


RESULTS
Overall contrast enhancement was rated sufficient for diagnosis in all examinations and both contrast agents. Vascular enhancement was rated comparable with exception of the aorta, the peripheral intrahepatic veins, and the central lung vessels (p = 0.0182, p = 0.0053, p = 0.0083, in favor of Gd-DTPA). Quantitative evaluation revealed no statistically significant differences in parenchymal and vascular signal-to-noise ratios with exception of the aorta, and the central pulmonary artery (67.4 vs. 89.3; p = 0.0421, 44.5 vs. 59.5; p = 0.0446 respectively, in favor of Gd-DTPA).


CONCLUSIONS
The contrast enhancement after gadoxetic acid is comparable to Gd-DTPA and appears suitable for comprehensive TNM-staging by combining high accurate liver-specific phases with efficacious vascular enhancement in the different anatomic regions.
Huppertz
Alexander
A
Imaging Science Institute Charité, Berlin, Germany. Alexander.Huppertz@charite.de
Franiel
Tobias
T
Wagner
Moritz
M
Püttcher
Olaf
O
Wagner
Joachim
J
Rief
Matthias
M
Schwenke
Carsten
C
Hamm
Bernd
B
Strassburg
Joachim
J
D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008099:Liver / Q000098:blood supply*; D008168:Lung / Q000098:blood supply*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010388:Pelvis / Q000098:blood supply; D011446:Prospective Studies; D012004:Rectal Neoplasms; D012044:Regression Analysis; D051598:Whole Body Imaging
D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA