[1] UNIV UTAH, MED CTR, DEPT RADIOL, SALT LAKE CITY, UT 84132 USA
[2] VET ADM HOSP, DEPT RADIOL, SAN FRANCISCO, CA USA
[3] UNIV CALIF, SCH MED, DEPT RADIOL, SAN FRANCISCO, CA USA
[4] UNIV CALIF, SCH PHARM, DEPT PHARM & PHARM CHEM, SAN FRANCISCO, CA USA