==inizio abstract==

Radiation exposure in the follow-up after partial nephrectomy (PN) is a matter of concern. Little literature illustrate normal versus abnormal post PN imaging of the kidney and its evolution during the time.
Material and Methods:
We reviewed 160 follow-up CT-scans from 40 patients who underwent PN for renal cell carcinoma (RCC) pT1-2. Imaging findings were grouped in 5 groups: 1) parenchymal defects, 2) peripheral fat stranding,3) hyperdensity spots on native scans, 4) membranes, 5) fluid collections (sub-capsular or extra-capsular). Every patient underwent 2 or more CT-scans. CT Technique: All triple-quadruple-phase technique were used. Multiplanar reconstruction imaging and 3D post-processing tools to complete CT evaluation (maximum intensity-projection images) were applied.
Tumors were mostly T1 (95%), clear cell carcinomas (62.5%), Fuhrmann grade 1-2 (80%). Median follow-up was 29 months.
Imaging features
Parenchymal defects (82.5%) and fat stranding (87.5%) were the most common cross-sectional imaging findings. Both mostly persisted.
Hyperdensities on native scans were reported in 27.5% of the cases and were usually haemostatic agents or calcification.
Membranes were seen in 37.5% of the cases and tend to remain stable.
Overall, fluid collections were reported in 65% of the cases. The sub-capsulars (47.5%) were still visible after 20 months in 11.1% and extra-capsulars (17.5%) resolved nearly completely within 12 months.
CT-image defects in the follow-up of T1-2 after PN RCC have a benign evolution overtime. Follow-up schedules should not be intensified in the presence of image cathegories we described. Multiplanar evaluation of post-surgical kidney is essential to represent parenchymal defects and exclude the presence of tumor residual/recidive.

==fine abstract==