Discrepancy in T1 and T2 shortening of the globus pallidus in hepatic insufficiency: evaluation by susceptibility-weighted imaging.

Purpose: We assessed the signal of the globus pallidus (GP) in cases of hepatic insufficiency, especially to evaluate the degree of discrepancy in paramagnetic effects on shortening of T(1) and T(2)* using susceptibility-weighted images (SWI).

Materials And Methods: Seven patients with hepatic insufficiency underwent magnetic resonance (MR) examinations that included T(1)-weighted images (T(1)WI), T(2)-weighted images (T(2)WI), and SWI on a 1.5-tesla MR imager, and we compared their results to those of controls. On T(1)WI and T(2)WI, we measured signal intensity in the GP and posterior segment of the putamen (Put) to obtain a signal ratio (GP/Put ratio), and on SWI, we classified signal intensity into 4 grades: A, higher than the cortex; B, lower than the cortex and higher than the cerebrospinal fluid (CSF); C, lower than the CSF and higher than the red nucleus; and D, lower than the red nucleus.

Results: In the 7 patients with hepatic insufficiency, the mean GP/Put ratio was significantly higher on T(1)WI and T(2)WI than those values in controls. On SWI, we classified 2 cases each as Grade A, Grade B, and Grade C, and one as Grade D. Although the signal of the GP was elevated on T(1)WI, there was no decrease in signal on T(2)WI. On SWI, we obtained no low signal intensity.

Conclusion: In patients with hepatic insufficiency, the globus pallidus did not show low signal intensity on either T(2)WI or SWI. Hyperintensity of the GP on T(1)WI without hypointensity on T(2)WI, or even SWI, suggests a discrepancy between paramagnetic effect on T(1) and T(2) shortening that reflects the accumulation of manganese and the presence of hepatic insufficiency.