Effect of increasing the flip angle during the hepatocyte phase of gadobenate dimeglumine-enhanced 1.5T MRI in cirrhotic patients with hepatocellular carcinoma.
OBJECTIVE
To evaluate the effects of increasing the flip angle during the hepatocyte phase of gadobenate dimeglumine-enhanced magnetic resonance imaging (MRI) in cirrhotic patients with hepatocellular carcinoma (HCC).


METHODS
Sixty-three patients with liver cirrhosis underwent gadobenate dimeglumine-enhanced 1.5T MRI with 90-minute delayed hepatocyte phase with flip angles of 10°, 20°, 30°, consecutively. Relative enhancement and signal-to-noise ratio (SNR) of liver parenchyma at hepatocyte phase according to flip angle were calculated. The liver-to-lesion (low signal intensity HCCs, n = 63; ≥1 cm) and contrast-to-noise ratio (CNR) at the hepatocyte phase according to flip angle were calculated. Two radiologists independently assessed the presence of HCCs using a 5-point scale, and detection sensitivity of HCCs was calculated according to flip angle.


RESULTS
The relative enhancement of hepatic parenchyma differed significantly according to flip angle (10°, mean relative enhancement = 0.69 ± 0.46; 20°, mean relative enhancement = 0.63 ± 0.47; 30°, mean relative enhancement = 0.49 ± 0.45; P = 0.043). The SNR of hepatic parenchyma was significantly different according to flip angle (10°, mean SNR = 26.2 ± 5.6; 20°, mean SNR = 25.3 ± 5.7; 30°, mean SNR = 22.8 ± 6.1; P = 0.004). The CNR of lesion was not significantly different according to flip angle (10°, mean CNR = 7.5 ± 6.6; 20°, mean CNR = 10.2 ± 6.9; 30°, mean CNR = 10.1 ± 7.1; P = 0.051). The sensitivities with 10° and 20° for HCCs were significantly higher than those with 30° for one reader (P < 0.05).


CONCLUSIONS
In patients with cirrhosis, hepatocyte phase gadobenate dimeglumine-enhanced 1.5T MRI with 20° flip angle should be recommended rather than 10° and 30° flip angle.
Department of Radiology, CHA Bundang Medical Center, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea.
Eun Jung
EJ
Lee
Department of Radiology, CHA Bundang Medical Center, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea.
Dae Jung
DJ
Kim
Department of Radiology, Yonsei University College of Medicine, Gangnam Severance Hospital, Seoul, Republic of Korea.
Eun-Suk
ES
Cho
Department of Radiology, CHA Bundang Medical Center, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea.
Kyoung Ah
KA
Kim
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D003287:Contrast Media / Q000737:chemistry; D005260:Female; D022781:Hepatocytes / Q000166:cytology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008103:Liver Cirrhosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D008113:Liver Neoplasms / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives* / Q000737:chemistry; D008875:Middle Aged; D009942:Organometallic Compounds / Q000737:chemistry*; D011871:Radiology; D012189:Retrospective Studies; D059629:Signal-To-Noise Ratio
D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine
flip angle; gadobenate dimeglumine; hepatocellular carcinoma; liver; magnetic resonance