Dual-layer spectral CT virtual-non-contrast images aid in parathyroid adenoma analysis and radiation dose reduction: confirmation of findings from dual-energy CT.

4D-parathyroid CT scans have become a mainstay in the evaluation and pre-surgical planning for parathyroid adenomas. Most protocols typically rely on non-contrast images, prior to the arterial and delayed phases. Previous reports with dual-energy CT imaging have highlighted the utility of virtual non-contrast images to help reduce radiation dose while maintaining diagnostic accuracy. Herein, we report two cases of surgically proven parathyroid adenomas diagnosed with 4D-parathyroid CT scans performed on dual-layer spectral scanners, and in retrospect highlight the utility of virtual non-contrast images. To our knowledge, this report provides the first description of virtual non-contrast images from dual-layer spectral CT scanners that could aid in the diagnosis of parathyroid adenomas, confirming similar findings described with dual-energy CT scanners.

Accuracy and cost analysis of image-guided sinus surgery.

The use of image guidance in FESS has become widespread over the past several years. Numerous studies involving large numbers of patients illustrate the accuracy of these systems. In addition, case reports concerning patients who have extensive sinonasal neoplasms or distorted anatomy serve to demonstrate the usefulness of IGS. Studies by Metson et al [22] and Fried et al [23] have also investigated the surgeons' opinions of IGS. The vast majority of sinus surgeons have been pleased with the systems' ease of use and accuracy. Increased confidence in precisely localizing anatomical structures was the primary benefit. The major drawback to using image-guided systems was the increased operative time. Despite this, almost all surgeons who were questioned reported that they expect to increase their use of IGS in the future. By giving the surgeon real-time localization of surgical instruments, IGS could result in safer and more thorough surgery. This effect could have major implications for difficult surgeries in which distorted anatomy or extensive disease might otherwise result in incomplete eradication of the disease process. Studies examining these issues are necessary before a final conclusion can be drawn as to whether the accuracy achieved with current systems is truly beneficial and the cost is worth incurring.