[1] UNIV MELBOURNE, ROYAL MELBOURNE HOSP, DEPT RADIOL, MELBOURNE, VIC 3050, AUSTRALIA
[2] MIDDLESEX HOSP, DEPT RADIOL, LONDON W1, ENGLAND
[3] UNIV CALIF SAN DIEGO, MED CTR, DEPT MED, SAN DIEGO, CA 92103 USA
[4] UNIV S FLORIDA, MED CTR, DIV DIGEST DIS & NUTR, TAMPA, FL 33620 USA
[5] UNIV CALIF SAN DIEGO, MED CTR, DEPT RADIOL, SAN DIEGO, CA 92103 USA