Minimally invasive surgery of the most lethal disease worldwide, coronary artery disease, benefits from better diagnostic tools during the treatment. With this in mind, a novel concept is introduced for intravascular ultrasound on a 360 μm diameter guidewire. The complex manufacture of this medical instrument, and other devices that require extreme miniaturization, will benefit from our previously presented Flex-to-Rigid assembly platform. However, currently the scalability of this technology is limited by etch-dependent effects. But with an innovation on the process flow presented here, the required smaller, well-defined, arbitrary shaped rigid islands with flexible interconnects between them were fabricated, therefore making it possible to manufacture this device.