Abstract
Purpose :
Ultrasonography (USG) is an important imaging tool for the diagnosis and follow-up of benign and malignant intraocular tumors. However, with routine USG, the assessment of blood flow may be erroneous because of altered blood flow within the tissue and the equipment's poor sensitivity to low-velocity blood flow. We hypothesize contrast-enhanced ultrasound (CEUS) using focused microbubble technique would help quantify microvascular changes within the lesions, thereby providing a new approach for diagnosing and differentiating benign and malignant choroidal lesions.
Methods :
One patient with choroidal hemangioma (CH) and choroidal melanoma (CM) was selected for this study. Definity®, which contains perflutren microbubbles, was administered as a slow IV bolus (1 ml) followed by a normal saline 5 cc flush. CEUS was performed for two minutes post injection of the dye with continuous video recording. The contrast enhancement was calculated using Matlab (The MathWorks, USA) using pre- and post-injection frames within a time window of 10 s to 60 s. First, a single frame from the pre-injection video was chosen (Fig. 1), and the region of interest (ROI) was selected within the bulging choroidal lesion. Next, corresponding ROIs were selected from the bulging choroidal lesion of post-injection frames within 10 s to 60 s at 1 s intervals. The mean intensity was calculated for each ROI, and the time-averaged difference in pixel intensities of the post-injection frames relative to the reference pre-injection frame was calculated.
Results :
The time-averaged contrast increased by a percentage difference of 9.9% ± 5.2% (Mean ± SD) for CH and decreased by 4.2% ± 4.7% for CM (Fig. 2). Furthermore, the intensity within the normal choroidal region was higher compared to the choroidal tumor region for both CH and CM. This observation may be attributed to higher vascularity in the choroid region compared to the tumor or the transducer being focused closer to the choroid.
Conclusions :
Quantitative intensity-based contrast enhancement using novel B-scan CEUS can be a potentially promising tool for differentiating benign and malignant choroidal lesions.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.