CT-Guided Biopsy of Entirely Endophytic Small Renal Masses: Diagnostic Rates and Complications Using Standard-Dose and Reduced-Dose CT Protocols.

OBJECTIVE: The objective of this study was to compare diagnostic rates and complications using standard-dose and reduced-dose CT protocols for CT-guided biopsies of entirely endophytic small renal masses.

MATERIALS AND METHODS: A total of 73 patients with 74 tumors underwent CT-guided biopsy of entirely endophytic small renal masses (≤ 4 cm). Diagnostic rates, histologic findings, radiation doses, complication rates, and procedure duration were assessed by retrospective review of charts and images and were compared for the standard-dose and reduced-dose groups.

RESULTS: Biopsy was performed using the standard-dose CT protocol (mean reference tube current-exposure time setting, 205.0 ± 19.0 [SD] mAs) for 43 lesions, and the reduced-dose CT protocol (reference tube current-exposure time setting, 42.0 ± 7.5 mAs) for 31 lesions. In the reduced-dose group, there were 29 lesions (94%) with diagnostic results. In the standard-dose group, biopsies of 42 lesions (98%) yielded diagnostic results. No complications that needed intervention or hospitalization occurred in either group. The dose-length product (DLP) was significantly higher in the standard-dose group than the reduced-dose group (574 ± 232 vs 152 ± 63 mGy × cm, respectively; p < 0.05). The mean procedure duration did not differ significantly for the two groups.

CONCLUSION: Biopsy of entirely endophytic small renal masses that is performed with guidance using a reduced-dose CT protocol gives diagnostic results similar to a standard-dose CT protocol without any increase in complication rate or procedure duration.