Amebic liver abscess: diagnosis and treatment evaluation with MR imaging.

Magnetic resonance images were obtained before and after treatment in 17 patients with 29 amebic liver abscesses. Pretreatment T1-weighted images showed a sharply circumscribed, heterogeneous, low-signal-intensity mass, devoid of normal hepatic tissue and corresponding to the abscess cavity as measured sonographically. T2-weighted images showed the abscess cavity as a hyperintense region and also showed a larger region of hyperintensity extending from the cavity margins to the liver surface, corresponding to edematous but morphologically normal liver tissue. After treatment, the abscess cavity became homogeneously hypointense on T1-weighted images, corresponding to liquefaction of the abscess center. With successful treatment, concentric rings corresponding to (a) an inner margin of inflamed granulation tissue, (b) bands of type I collagen, and (c) the outer margin of atrophic and/or mildly inflamed liver tissue became prominent on T1- and T2-weighted images. T2-weighted images showed rapid resolution of the perifocal hepatic edema.