In a problem of unknown etiology, a prediagnosis by the dr for the radiologist is bad b/c then the radiologist is prejudiced and misses imp info?

Not necessarily: Radiologists are trained to be as objective as possible when reviewing imaging studies. Yes, it is possible for the radiologist to be biased by an established diagnosis, but most radiologists are taught to be very thorough and come to conclusions based on the imaging findings regardless of the clinical information. In most cases, clinical info is helpful to narrow down differential diagnosis.

No!: Everytime a radiologist reads a study there must be clinical information to justify the exam, or the insurer or medicare will not pay. So a history is required. Radiologists rely on pertinent clinical information to key in on pathology, but read the entire examination and attempt to never miss any important findings. Therefore if there is a negative exam, they should call the radiologist.