Methods and apparatuses for space-optimized visualization catheters are provided. Some embodiments utilize complimentary metal-oxide-semi-conductor (“CMOS”) technology integrated into a CMOS camera train holder system that may be a stand-alone component for use with a visualization catheter, such as a baby endoscope, or may be fabricated/extruded as a part of the catheter itself. Some embodiments of apparatuses, methods, and equivalents thereto provide better direct visual feedback to the medical personnel performing the procedure while providing a similarly-sized outer diameter visualization catheter device having an increased space therein for additional lumens and equipment or by reducing the overall outer diameter of the visualization catheter.