Apparatus and methods are provided including, while an endoluminal data-acquisition device is being moved through a lumen of a subject, acquiring a plurality of endoluminal data points of the lumen using the endoluminal data-acquisition device. At at least one location it is determined that an event occurred, the event causing the endoluminal data-acquisition device not to acquire a single endoluminal data point at the location. The endoluminal data points are displayed in a stack, in which the endoluminal data points are positioned at locations corresponding to relative locations within the lumen at which the endoluminal data points were acquired, and in which the event is accounted for. Other applications are also described.