Improved liver lesion conspicuity by increasing the flip angle during hepatocyte phase MR imaging

Abstract

High flip angle delayed hepatocyte phase imaging is a useful adjunct to standard enhanced MRI of the liver. It allows for better sensitivity in focal lesion detection, particularly for small lesions. Secondarily, this technique increases the conspicuity of the biliary system, which is an additional benefit of delayed imaging with hepatobiliary contrast agents.

Liver MRI in the hepatocyte phase with gadolinium‐EOB‐DTPA: Does increasing the flip angle improve conspicuity and detection rate of hypointense lesions?

“…This is in contrast to the recommendations of the consensus report of the Second International Forum for Liver MRI published in 2009 (23). The use of faster, higher spatial resolution 3D pulse sequences is well supported by more recent work from around the world (20,(24)(25)(26)(27)(28). We also noted that although this technique was useful at both 3T and 1.5T, the increased projected energy deposition at 3T (SAR) caused the MR scanner console to reduce the FA of the pulse sequence in four of seven cases performed at 3T in our initial review, a phenomenon that has been previously described (20).…”

Rules, Roles, and Room for Discussion in Gadoxetic Acid-enhanced Magnetic Resonance Liver Imaging: Current Knowledge and Future Challenges

“…Yet, a larger ‰ip angle may be optimal to maximize tumor-toliver contrast because the presence of contrast agent can shorten T 1 relaxation time in the liver during the hepatocyte phase; recent reports suggests a 309angle. 30,31 A greater ‰ip angle can be especially helpful when imaging patients with chronic liver disease, whose impaired hepatic function and/or gadoxetic acid uptake may make it di‹cult to obtain su‹cient tumor-to-liver contrast. 32 Respiratory-triggered high resolution 3D-GRE sequence using navigator echo has been proposed to obtain hepatocyte phase images with improved spatial Magnetic Resonance in Medical Sciences resolution, especially for the z axis.…”

“…HA is a benign neoplasm composed of hepatocytes and is treated with surgical resection if the HA is considered at high risk for spontaneous hemorrhage or malignant transformation. 30,32,39,58 Recent studies have provided evidence that gadoxetic acid-enhanced MR imaging in general and hepatocyte phase images in particular greatly facilitate the diŠerential diagnosis of these 2 lesions. Most FNHs are strongly enhanced during the arterial phase and show hyperintensity on hepatocyte phase images (Fig.…”

Navigated three-dimensional T1-weighted gradient-echo sequence for gadoxetic acid liver magnetic resonance imaging in patients with limited breath-holding capacity

“…Considering that hepatic vessel clarity can be the result of spatial resolution and contrast resolution, and that we used the same FA (12°) for these two sequences, the same FA may have attributed to the similar contrast between the liver and hepatic vessels on HBP images. We believe that the use of a higher FA [37,38] which was suggested in a previous study [13] on navigated T1WI may further improve the contrast resolution. Finally, long acquisition time of navigated LAVA impedes its application to dynamic sequences, especially AP imaging on gadoxetic acid MRI, which is a weakness of navigated LAVA compared to recently developed techniques such as compressed sensing or non-Cartesian reconstruction methods.…”