Traveling from Muang Khoa-Luang Nam Tha

Does anyone know if it is possible to travel from the Muang Khoa border crossing with Vietnam to Laung Namtha by river, or does river travel take you down to Luang Prabang? The maps I'm looking at are hard to discern.

can find good maps at ecotourismlaos.com

theoretically possible by a pretty roundabout way (Nam Ou > Mekong > Nam Tha rivers then land transport for final bit to Luang Namtha) when water levels are high enough ;)

thanks!

Far faster and cheaper just to take a sonthaew from Muang Khua to Oudomxai/Muang Xai and then tranfer at the bus station for transport to Luang Namtha. Easily done in a day.