In the context of the findings you've described—areas of heterogeneous enhancement with loss of corticomedullary differentiation in both kidneys suspicious for pyelonephritis, particularly on the right side—urinalysis plays a crucial role in confirming the diagnosis.

Urinalysis in patients with pyelonephritis typically shows significant pyuria, which is an increased number of white blood cells (WBCs) in the urine, often exceeding 20 WBCs per high power field (hpf) (Medscape Reference). The presence of pyuria is a key indicator of infection, and it can be rapidly assessed with the leukocyte esterase test, which detects the presence of WBCs (AAFP, 2005).

Furthermore, urinalysis may also reveal a positive nitrite test, indicating the presence of certain bacteria such as Escherichia coli, which are commonly associated with urinary tract infections that can lead to pyelonephritis (AAFP, 2011; NIDDK). Other findings in urinalysis might include the presence of bacteria, blood, and possibly proteins, all of which can further support the diagnosis of pyelonephritis.

In summary, correlating the imaging findings of pyelonephritis with urinalysis results—specifically assessing for pyuria, positive leukocyte esterase, and any noted bacteria—would be highly beneficial in confirming the diagnosis and guiding treatment. For further detailed reading, you can refer to the following resources: Medscape Reference, AAFP, BMJ Best Practice, NIDDK, and Urology Health.