Liver MRI in the hepatocyte phase with gadolinium-EOB-DTPA: does increasing the flip angle improve conspicuity and detection rate of hypointense lesions?
OBJECTIVE
To compare conspicuity and detection rate of hypointense lesions on T1-weighted (T1w) gradient echo (GRE) sequences with low and high flip angles (FA) in hepatocyte phase magnetic resonance imaging (MRI) using gadoxetate disodium.


METHODS
This Health Insurance Portability and Accountability Act (HIPAA)-compliant study was Institutional Review Board (IRB)-approved. The study population consisted of patients with hypointense liver lesions undergoing MRI with gadoxetate disodium, with hepatocyte-phase fat suppressed 3D T1w GRE sequences at both low (10-12°) and high (30-35°) FA. Contrast-to-noise ratios (CNRs) were calculated for liver parenchyma vs. large lesions and common bile duct (CBD) vs. liver. Three radiologists each assigned a conspicuity score (CS) for each lesion detected at low or high FA. Paired Student's t-tests compared the lesion detection (LD) rate using only the hepatocyte phase data set compared with the entire MRI examination, and CS for low and high FA.


RESULTS
In all, 57 large and 70 small lesions were identified in 18 patients. Average LD and CS were significantly greater at high FA versus low FA overall (LD 89.0% vs. 79.5%; CS 2.8 vs. 2.2; P < 0.05) and for small lesions (81.4% vs. 65.7%; 2.5 vs. 1.8; P < 0.05). Average liver-to-lesion CNR for large lesions and CBD-to-liver CNR was significantly greater at high FA (P < 0.05).


CONCLUSIONS
Increasing the FA in hepatocyte phase MRI with gadoxetate disodium improves hypointense lesion detection and conspicuity, particularly for small lesions.
Department of Radiology, Duke University Medical Center, Durham, North Carolina, USA.
Mustafa R
MR
Bashir
Daniela B
DB
Husarik
Tim J
TJ
Ziemlewicz
Rajan T
RT
Gupta
Daniel T
DT
Boll
Elmar M
EM
Merkle
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003287:Contrast Media / Q000493:pharmacokinetics*; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D022781:Hepatocytes / Q000378:metabolism*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008107:Liver Diseases / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity
D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA