Priscilla Machado MD, Abstract Co-Author: Grant, Toshiba Corporation Equipment support, Toshiba Corporation

Sharon Rebecca Segal DO, Abstract Co-Author: Nothing to Disclose

Andrej Lyshchik MD, PhD, Abstract Co-Author: Nothing to Disclose

Flemming Forsberg PhD, Presenter: Equipment support, Toshiba Corporation Research collaboration, General Electric Company Research collaboration, Analogic Corporation Research collaboration, Toshiba Corporation Speakers Bureau, Toshiba Corporation

To evaluate the flow imaging capabilities of a new prototype ultrasound (US) image processing technique (SMI; Toshiba Medical Systems, Tokyo, Japan) for depiction of microvascular flow in normal thyroid tissue and thyroid nodules compared to standard color and Power Doppler imaging (CDI and PDI).

SMI is a novel, microvascular flow imaging mode implemented on the Aplio 500 US system (Toshiba). SMI utilizes advanced clutter suppression to extract flow signals from large to small vessels and depicts this information as a color overlay image or as a monochrome map of flow. Ten (10)  healthy volunteers and 22 patients, with 25 thyroid nodules, scheduled for US guided fine needle aspiration were enrolled in this prospective study. Subjects underwent US examination consisting of grayscale US, CDI and PDI followed by color and monochrome SMI and pulsed Doppler. In the volunteers, pulsed Doppler guided by the 4 flow modes determined the lowest velocity measurable within the normal thyroid microvasculature and results were compared using a one-way ANOVA. Two radiologists independently analyzed still images and digital clips scoring overall flow detection, vessel branching details and noise on a subjective scale of 1 (worst) to 10 (best). Scores were compared (on a per nodule basis) using a non-parametric Wilcoxon signed rank test.

For the volunteers SMI captured microvasculature with lower velocity than CDI and PDI (2.2 ± 0.35 and 2.1 ± 0.32 cm/s vs. 2.6 ± 0.44 and 2.8 ± 0.77 cm/s; p < 0.012). In all cases SMI showed microvascular flow with significantly higher image scores and provided better depiction of the vessel branching details compared to CDI and PDI (SMI scores > 5.4 and CDI/PDI scores < 4.9; p < 0.0001). Clutter noise was significantly higher in monochrome SMI mode than in the other modes, including color SMI (monochrome SMI scores < 4.5 while others were > 6.4; p < 0.001).

The novel SMI mode consistently showed more detailed thyroid flow with smaller branches and lower velocities than CDI and PDI.

This new flow mode may be useful for providing a better understanding of the vascularity of thyroid nodules.

Machado, P, Segal, S, Lyshchik, A, Forsberg, F, Thyroid Evaluation with a Novel Microvascular Flow Technique.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14013550.html