BACKGROUND: Tyrosine kinase inhibitor (Gleevec or STI-571) must be considered 
the treatment of choice for metastatic gastrointestinal stromal tumors (GISTs). 
The purpose of this article is to address and illustrate a long-term follow-up 
of computed tomographic (CT) radiologic findings in patients with metastases 
from GIST after Gleevec treatment.
METHODS: We performed a retrospective review of seven patients (four male, three 
female) with unresectable metastases from GIST who were treated with STI-571 in 
a 1-year period. Patients were followed every 2-4 months by contrast-enhanced CT 
for up to 12 months. The size and attenuation of hepatic and peritoneal 
metastases on CT were measured and correlated.
RESULTS: Hepatic metastases from GISTs showed significant decreased attenuation 
from a mean of 60 HU to a mean of 32 HU (p < 0.01) in the first 2 months and 
continued decreasing attenuation to 23 HU at the 12-month follow-up. These 
metastases superficially resembled simple cysts. Most metastases became smaller, 
with more defined borders, after treatment. Histologic examination in a resected 
specimen revealed hepatic cyst with no residual tumor cells, regression of 
omental lesions, and extensive necrosis.
CONCLUSIONS: CT findings of unresectable hepatic and peritoneal metastases from 
GIST displayed decreasing, near cystic attenuation and size as an effective 
regression in response to STI-571 treatment.