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Objectives: To establish national reference levels (RLs) in interventional procedures under CT guidance as required by the 2013/59/Euratom European Directive., Methods: Seventeen categories of interventional procedures in thoracic, abdominopelvic, and osteoarticular specialties (percutaneous infiltration, vertebroplasty, biopsy, drainage, tumor destruction) were analyzed. Total dose length product (DLP), number of helical acquisitions (NH), and total DLP for helical, sequential, or fluoroscopic acquisitions were recorded for 10 to 20 patients per procedure at each center. RLs were calculated as the 3rd quartiles of the distributions and target values for optimization process (TVOs) as the median. RLs and TVOs were compared with previously published studies., Results: Results on 5001 procedures from 49 centers confirmed the great variability in patient dose for the same category of procedures. RLs were proposed for the DLPs and NHs in the seventeen categories. RLs in terms of DLP and NH were 375 mGy.cm and 2 NH for spinal or peri-spinal infiltration, 1630 mGy.cm and 3 NH for vertebroplasty, 845 mGy.cm and 4 NH for biopsy, 1950 mGy.cm and 8 NH for destruction of tumors, and 1090 mGy.cm and 5 NH for drainage. DLP and NH increased with the complexity of procedures., Conclusions: This study was the first nationwide multicentric survey to propose RLs for interventional procedures under CT guidance. Heterogeneity of practice in centers were found with different levels of patient doses for the same procedure. The proposed RLs will allow imaging departments to benchmark their practice with others and optimize their protocols., Key Points: • National reference levels are proposed for 17 categories of interventional procedures under CT guidance. • Reference levels are useful for benchmarking practices and optimizing protocols. • Reference levels are proposed for dose length product and the number of helical acquisitions.

Purpose: Using a limited temporal resolution dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) dataset to assess the impact of the arterial input function (AIF) choice on the transfer constant (K(trans) ) to distinguish prostate carcinoma (PCa) from benign tissue., Materials and Methods: Thirty-eight patients with clinically important peripheral PCa (≥0.5 cc) were retrospectively studied. These patients underwent 1.5T multiparametric prostate MR with PCa and benign regions of interest (ROIs) selected using a visual registration with morphometric reconstruction obtained from radical prostatectomy. Using three pharmacokinetic (PK) analysis software programs, the mean K(trans) of ROIs was computed using three AIFs: an individual AIF (Ind-AIF) and two literature population average AIFs of Weinmann (W-AIF) and of Fritz-Hansen (FH-AIF). A pairwise comparison of the area under the receiver operating characteristic curves (AUROCC) obtained with different AIFs was performed., Results: AUROCCs obtained with W-AIF (ranging from 0.801 to 0.843) were significantly higher than FH-AIF (ranging from 0.698 to 0.780, 0.002 ≤ P ≤ 0.045) and similar to or higher than Ind-AIF (ranging from 0.591 to 0.839, 0.014 ≤ P ≤ 0.9). Ind-AIF and FH-AIF provided similar AUROCC (0.34 ≤ P ≤ 0.81). The pairwise correlation of K(trans) values was moderate to very strong when comparing W-AIF with FH-AIF (the Spearman's correlation coefficients [SCCs] ranged from 0.55 to 0.93) and very weak to moderate when comparing W-AIF with Ind-AIF (the SCCs ranged from 0.018 to 0.59) or FH-AIF with Ind-AIF (the SCCs ranged from 0.30 to 0.51)., Conclusion: W-AIF yielded a higher performance than FH-AIF and a similar or higher performance than Ind-AIF in distinguishing PCa from benign tissue., (© 2015 Wiley Periodicals, Inc.)

Objectives: Endovascular embolization is a valid option for the management of visceral artery aneurysms. Imaging is crucial for providing anatomical assessments, but preoperative non-invasive investigations may not be exhaustive. The aim of this work is to present preliminary experience with the use of three-dimensional rotational angiography (3DRA) in this particular theatre., Methods: Seven patients were treated for eight visceral aneurysms (six splenic and two renal) by endovascular embolization. 3DRA was performed before the treatment using a standard protocol. Different parameters (location of the lesion, the afferent and efferent vessels, aneurysm neck, vascular diameters, working incidence) were analyzed., Results: 3DRA was successfully accomplished in all procedures. Mean aneurysm diameter was 23 mm and mean C-arm working incidence was 29° (R-L) and 9° (C-C). The sandwich technique was used in four lesions and the packing in the remaining four. Technical success was 100 %. The mean radiation dose per procedure was 291 600 mGy.cm(2). The mean procedural time was 2.25 hours. There were no immediate or short-term complications., Conclusions: 3DRA could be an interesting intraoperative tool to provide anatomical and technical assessments of the visceral arteries necessary for endovascular treatment, especially when information from preoperative imaging is not exhaustive., Key Points: Endovascular embolization is a valid alternative solution for visceral artery aneurysm treatment. Imaging is crucial for anatomical assessments and treatment guidance. 3DRA can contribute to endovascular treatment in lieu of preoperative imaging.