Analysis of Factors Affecting Air Kerma Area Product Obtained during Uterine Artery Embolization Procedures Using Logistic Regression

Radiation metrics for vascular and interventional radiology procedures in a tertiary care institution: A retrospective cohort study over 5-years

OBJECTIVES

To evaluate the radiation metrics from frequently carried out vascular and interventional radiology (VIR) procedures at a tertiary care institution and compare them to international diagnostic reference levels (DRLs).

METHODS

A retrospective study of the radiation metrics of VIR-procedures carried out from January 2015 to December 2019. The collected data included age, gender, height and weight, reference point air kerma (mGy), dose area product (DAP; Gy.cm2), and fluoroscopy time (min.) The body mass index (BMI) and peak skin dose were calculated. The study cohort included 8942 adult patients (54.4% male, 45.6% female) with a mean age of 56.96 years and mean BMI of 26.86.

RESULTS

Transjugular intrahepatic portosystemic shunt (TIPS) creation recorded the highest mean fluoroscopy time of 69.41 min., followed by central venous recanalization 39.67min. TIPS creation had the highest mean DAP (1161.16 Gy.cm2), followed by trans arterial chemoembolisation (TACE) (500.63Gy.cm2). TIPS creation was associated with the highest peak skin dose (2766.81mGy), followed by TACE (1588.29mGy). Compared to other studies, TIPS creation and TACE are associated with significantly higher DAP.

CONCLUSION

Majority of VIR-procedures demonstrate no significant institutional variations in dosimetry compared to other studies. Using these studied values as reference levels may help identifying procedures that need quality control to minimize unnecessary exposures.

Predictors of radiation dose for uterine artery embolisation are angiography system-dependent

This study sought to achieve radiation dose reductions for patients receiving uterine artery embolisation (UAE) by evaluating radiation dose measurements for the preceding generation (Allura) and upgraded (Azurion) angiography system. Previous UAE regression models in the literature could not be applied to this centre's practice due to being based on different angiography systems and radiation dose predictor variables. The aims of this study were to establish whether radiation dose is reduced with the upgraded angiography system and to develop a regression model to determine predictors of radiation dose specific to the upgraded angiography system. A comparison between Group I (Allura,n= 95) and Group II (Azurion,n= 95) demonstrated a significant reduction in kerma-area product (KAP) and Ka, r (reference air kerma) by 63% (143.2 Gy cm²vs 52.9 Gy cm²;P< 0.001,d= 0.8) and 67% (0.6 Gy vs 0.2 Gy;P< 0.001,d= 0.8), respectively. The multivariable linear regression (MLR) model identified the UAE radiation dose predictors for KAP on the upgraded angiography system as total fluoroscopy dose, Ka, r, and total uterus volume. The predictive accuracy of the MLR model was assessed using a Bland-Altman plot. The mean difference was 0.39 Gy cm²and the limits of agreement were +28.49 and -27.71 Gy cm², and thus illustrated no proportional bias. The resultant MLR model was considered system-dependent and validated the upgraded angiography system and its advance capabilities to significantly reduce radiation dose. Interventional radiologist and interventional radiographer familiarisation of the system's features and the implementation of the newly established MLR model would further facilitate dose optimisation for all centres performing UAE procedures using the upgraded angiography system.