ACUTE EFFECTS OF SHOCK-WAVES ON TUMORS ASSESSED BY MAGNETIC-RESONANCE-IMAGING - POSSIBLE ROLE OF BLOOD-FLOW REDUCTION

RATIONALE AND OBJECTIVES. The effects of shock waves on experimental t umors in vivo by gadolinium+-DTPA-enhanced magnetic resonance imaging (MRI) are assessed. METHODS. Two amelanotic hamster melanomas were imp lanted in the dorsal skin of 19 hamsters. In experiment 1 (n = 7), MRI of untreated tumors was performed before, and 5 and 15 minutes after intravenous injection of Gd+-DTPA. In experiment 2 (n = 12), 200 shock waves were applied on one of the implanted tumors. Magnetic resonance imaging was performed 15 minutes after treatment before, and 5 and 15 minutes after injection of Gd+-DTPA. RESULTS. In experiment 1, signal intensities (SI) of untreated tumors increased after injection of Gd-DTPA. In experiment 2, enhancement was significantly delayed in shock -wave-treated tumors as compared with controls. Histology of the treat ed tumors revealed vascular damage. CONCLUSION. Differences in enhance ment between shock-wave-treated and control tumors after injection of Gd+-DTPA are interpreted as the consequence of reduced and delayed acc umulation of Gd+-DTPA in treated tumors due to shock wave induced vasc ular damage and reduced tumor perfusion.