ultrasounded musculosketal joint injections

What needs to documented when performing a joint injection under ultrasound guidance. The CPT® guidelines only talk about keeping images but do I need more than to say, "ultrasound guided injection of left knee performed with 40mg kenalog, 3cc 1% lidocaine w/o complications" Will that suffice along with jpeg of the ultrasound view of the joint. Any more details needed?