Figure Kaplan-Meier curve of chronic black hole (cBH) persistence

Kaplan-Meier survival analysis of cBHs based on preexisting contrast-enhancing lesion (CEL) type, i.e., ring contrast-enhancing lesion (rCEL) vs nodular contrast-enhancing lesion (nCEL). The dashed line with closed symbols represents cBHs originating from nCELs. The solid black line with open symbols represents cBHs deriving from rCELs. In both curves, the circles stay for censored data. The censored data indicate that cBHs were still present but not followed at the conclusion of the study (i.e., month 24). As the curves show, there is a noticeable, but not significant, trend toward cBHs from preexisting rCELs lasting longer than cBHs from preexisting nCELs. The duration of a total of 170 cBHs was analyzed. Thirty-four cBHs derived from rCELs, 136 from nCELs.