FIG 3. An example of an unfavorable, large outflow tail (arrow), which can potentially serve as a thrombotic nidus.FIG 4. An example of a small detachment tail (arrow), defined as a tail extending into the parent vessel for a distance less than half the aneurysm-neck diameter.FIG 5. An extreme case of catheter-polymer adhesion, showing displacement of the polymer mass into the parent vessel when catheter detachment is attempted. In this example, the entire parent-vessel transverse diameter has been blocked by the pullout embolic mass, with as yet unsuccessful detachment.FIG 6. An example of polymer solution instillation in a nondependent aneurysm performed with complete flow arrest, showing rapid and gravitationally dependent outpouring of the embolic solution. The solution is pouring into the more gravitationally dependent parent vessel. In a terminal aneurysm model, such as the easily pictured basilar tip model, the unfavorable consequences can be readily appreciated