Yes! The radiologist is one of your doctors just like any other specialist. The radiologist establishes a doctor patient relationship with you even though you will likely never meet him. He will read one your medical imaging tests and send the report to the ordering doctor who may be your internist or specialist.
There is always a report produced for any medical imaging test you have. Most are dictated by radiologists. The radiologists name is somewhere in the report, usually at the bottom. A radiologist is a medical doctor or doctor of osteopathic medicine just like your other doctors. He will usually have an MD or DO after his name. The technologists name may also be on the report in some cases. The technologist performs the test.
Usually, your treating doctor will go over the results with you and plan your treatment. They know your history and complaints best. You can direct questions about your medical imaging tests to your primary or specialist doctor. Since you have access to your test results, you may have questions for the radiologist as well. Many radiology reports are difficult to understand for the non medically trained, and your doctor and the radiologist can help (hopefully this site will help as well).
While it is rare for a patient to contact the radiologist directly, this is definitely something you can do. You can simply call the hospital operator and ask to speak to the radiologist who interpreted your imaging test. The radiologist may not immediately know who you are since they interpret thousands of tests every year. They will however look you up and answer your questions or refer you to someone who can. It is also possible to direct any questions you may have to your primary or specialist doctor who can then call the radiologist directly and talk about the case.