Since the findings are normal then you can use the 592.0 if that was given for the test.
Here are some guidelines we use from RadiologyToday:
1. Signs and symptoms are acceptable diagnoses when a diagnosis is not confirmed. For example, if a patient is sent to a radiologist to rule out an ankle fracture and no fracture is found, medical necessity is nonetheless established if pain and swelling of the ankle are documented and coded. ICD-9-CM developers created the symptoms, signs, and ill-defined conditions chapter to handle situations in which a suspected illness is ruled out, but symptom codes appear in specific chapters as well. In the case of a ruled-out ankle fracture, the appropriate diagnostic codes would be found in the musculoskeletal chapter—719.07, Effusion of ankle and foot joint. The notes under this code state “Swelling of joint, with or without pain,” so a separate pain code would not be required.
2. Abnormal test results are acceptable diagnoses when further tests are negative. An abnormal blood test or x-ray may lead a provider to order a more complex test. When this occurs and the more extensive test is negative, the earlier positive test result can be listed as the primary diagnosis to establish the medical necessity of the follow-up exam. For example, an ultrasound shows an anomaly in the gastrointestinal tract of a patient, but the follow-up MRI is negative. The primary diagnosis for the MRI would be 793.4, Nonspecific abnormal findings
