Comparison of intraoperative 2D vs. 3D imaging in open reduction and fixation of distal radius fractures.

PURPOSE: In the volar plating of distal radius fractures, intraoperative three-dimensional (3D) imaging is designed to allow better judgment regarding screw and implant positioning compared with conventional intraoperative two-dimensional (2D) imaging. We evaluated the impact of these two imaging modalities on the rates of intraoperative revision and secondary surgery, as well as the need for implant removal during follow-up. METHODS: A retrospective analysis of consecutive patients who underwent volar plate osteosynthesis for isolated distal radius fractures between January 2008 and April 2016 was performed. Patient files were evaluated for intraoperative imaging findings, intraoperative and postoperative revision rates, and implant removal during follow-up. Additional analyses of radiation exposure, operation time, and hospitalization time were performed. RESULTS: A total of 314 patients were analyzed (mean age: 54 ± 19 years; 210 females). For 246 patients, only 2D imaging was performed, while the remaining 68 patients underwent both 2D and 3D imaging (O-Arm, Medtronic). The intraoperative revision rate was significantly (p < 0.001) higher with 3D imaging (32.4%) compared with 2D imaging (2.0%). The postoperative revision rates were similar between both the groups (2.9% vs. 2.0%; p = 0.674). Compared with 2D imaging, the use of the Medtronic O-Arm resulted in a significantly lower implant removal rate (8.8% vs. 18.7%; p = 0.036) during follow-up. CONCLUSION: Compared with conventional 2D imaging, the use of intraoperative 3D imaging significantly increased the intraoperative revision rate and has the potential for positive long-term effects for lowering the risk of requiring an implant removal.

256-MDCT for evaluation of urolithiasis: iterative reconstruction allows for a significant reduction of the applied radiation dose while maintaining high subjective and objective image quality.

PURPOSE: Multidetector CT (MDCT) is the established imaging modality in diagnostics of urolithiasis. The aim of iterative reconstruction (IR) is to allow for a radiation dose reduction while maintaining high image quality. This study evaluates its performance in MDCT for assessment of urolithiasis. MATERIALS AND METHODS: Fifty-two patients underwent non-contrast abdominal MDCT. Twenty-six patients were referred to MDCT under suspicion of urolithiasis, and examined using a dose-reduced scan protocol (RDCT). Twenty-six patients, who had undergone standard-dose MDCT, served as reference for radiation dose comparison. RDCT images were reconstructed using an IR system (iDose4™, Philips Healthcare, Cleveland, OH, USA). Objective image noise (OIN) was recorded and five radiologists rated the subjective image quality independently. Radiation parameters were derived from the scan protocols. RESULTS: The CTDIvol could be reduced by 50% to 5.8 mGy (P < 0.0001). The same reduction was achieved for DLP and effective dose to 253 ± 27 mGy*cm (P < 0.0001) and 3.9 ± 0.4 mSv (P < 0.0001). IR led to a reduction of the OIN of up to 61% compared with classic filtered back projection (FBP) (P < 0.0001). The OIN declined with increasing IR levels. RDCT with FBP showed the lowest scores of subjective image quality (2.32 ± 0.04). Mean scores improved with increasing IR levels. iDose6 was rated with the best mean score (3.66 ± 0.04). CONCLUSION: The evaluated IR-tool and protocol may be applied to achieve a considerable radiation dose reduction in MDCT for diagnostics of urolithiasis while maintaining a confident image quality. Best image quality, suitable for evaluation of the entire abdomen concerning differential diagnoses, was achieved with iDose6.