We appreciate the comments from Dr. Musi-alek on our article about the incidence of vulnerable plaques characterized by virtual histology intravascular ultrasound (VH IVUS). Some of the comments were addressed in the limitations section of our article, and we fully agree that some of those limitations could be surpassed using new technology and software (when properly validated), as the fully quantitative VH-IVUS image analysis algorithm (qVH-IVUS) recently introduced by his group. However, we consider that limitations secondary to the technique are so far unavoidable. For instance, due to the carotid artery diameter and the plaque size, it is well known that some part of the external plaque border can be outside of the current VH-IVUS field-of-image, whose diameter is 10X10 mm with the transducer in the center of the field. However, the usual eccentric positioning of the IVUS probe, which might be considered the culprit, cannot be, in our opinion, avoided by gentle manipulation of the guiding catheter or even the patient's head positioning. Only new and more efficient devices can probably overcome this situation in the future. We were aware of the impact of dense calcium on the measurement of necrotic core (NC). We did not include in Figure 1C the illustration of software-generated proportions of the plaque components as argued by Dr. Musialek, nor have we found these illustrations usually reported in other articles, including the one from Dr. Musialek. However, in our opinion, the red images in our figure corresponding to NC do not depend exclusively on the amount of calcium, but mainly correspond to true NC, as most of the red color is far from the calcium image. Moreover, the percentage of NC was around 25%, which likely corresponds to a calcified fibroathero-ma.
展开▼
