@mgurley
I tend to agree with you.
No doubts that let’s say Ultrasonography is a procedure. Techically both Ultrasonography and Pathology are diagnostic procedures. Main work in Ultrasonography is to analyze computer images you’ve got (so the part of procedure is done not on a patient directly) 
So we need to modify Procedure domain defition as you said.
and it totally fits in Measurement definition:
The MEASUREMENT table contains records of Measurement, i.e. structured values (numerical or categorical).
So there’s no place here for Ultrasound or Pathology report.