Retrospective case-control study on radiation dose for uterine artery embolization procedures

INTRODUCTION

Uterine artery embolization is performed in pre-menopausal women. Understanding the contribution of radiation dose at each stage of the procedure is important for potential dose reduction. The aim was to retrospectively analyse radiation dose on a per-procedural-stage basis, comparing digital subtraction angiography (DSA) and conventional roadmap (CRM).

METHODS

Group A consisted of 50 patients where DSA was used for road mapping at all stages: (I) Aortogram, (II) Left internal iliac artery (IIA) DSA, (III) Left uterine artery (UA) DSA, (IV) Right IIA DSA and (V) Right UA DSA. Group B included 50 patients, where CRM was used for road mapping at stages (II) and (IV).

RESULTS

For Group A, mean total dose-area product (DAP) was 39.7 Gy·cm2; mean DAP for each stage were (I) Aortogram = 3.4 Gy·cm2, (II) Left IIA DSA = 5.9 Gy·cm2, (III) Left UA DSA = 3.2 Gy·cm2, (IV) Right IIA DSA = 5.5 Gy·cm2 and (V) Right UA DSA = 3.0 Gy·cm2. For Group B, mean total DAP was 33.6 Gy·cm2, mean DAP for each stage were (I) Aortogram = 3.3 Gy·cm2, (II) Left IIA CRM = 1.5 Gy·cm2, (III) Left UA DSA = 3.3 Gy·cm2, (IV) Right IIA CRM = 1.5 Gy·cm2 and (V) Right UA DSA = 3.3 Gy·cm2. Fluoroscopy time was 10 and 9.4 min for Groups A and B, respectively.

CONCLUSION

The highest road-mapping radiation dose contribution was from bilateral IIA DSA. The use of CRM, intermittent fluoroscopy and elimination of the aortogram is recommended to further reduce procedural radiation dose.

Comparison of image quality assessments between interventional radiographers and interventional radiologists using digital subtraction angiography

Purpose

The aim of our study was to compare the image quality assessments of vascular anatomy between interventional radiographers and interventional radiologists using digital subtraction angiography (DSA) runs acquired during an interventional radiology procedure.

Approach

Visual grading characteristics (VGC) analysis was used to assess image quality by comparing two groups of images, where one group consisted of procedures in which radiation dose was optimized (group A, n = 10 ) and one group where dose optimization was not performed (group B, n = 10 ). The radiation dose parameters were optimized based on theoretical and empirical evidence to achieve radiation dose reductions during uterine artery embolization procedures. The two observer groups comprised of interventional radiologists ( n = 4 ) and interventional radiographers ( n = 4 ). Each observer rated the image quality of 20 DSA runs using a five-point rating scale.

Results

The VGC analysis produced an area under the VGC curve (AUC VGC ) of 0.55 for interventional radiographers ( P = 0.61 ) and AUCVGC of 0.52 for interventional radiologists ( P = 0.83 ). The optimization of radiation dose parameters demonstrated a reduction in kerma-area product by 35% ( P = 0.026 , d = 0.5 ) and reference air kerma (Ka, r ) by 43% ( P = 0.042 , d = 0.5 ) between group A and group B.

Conclusions

VGC analysis indicated that the image quality assessments of interventional radiographers were comparable with interventional radiologists, where a reduction in radiation dose revealed no effect on both observer groups regarding their image quality assessment of vascular anatomy.

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.

UTERINE ARTERY EMBOLISATION: CONTINUOUS QUALITY IMPROVEMENT REDUCES RADIATION DOSE WHILE MAINTAINING IMAGE QUALITY

The purpose of this study was to introduce a continuous quality improvement (CQI) program for radiation dose optimisation during uterine artery embolisation (UAE) and assess its impact on dose reduction and image quality. The CQI program investigated the effects of optimising radiation dose parameters on the kerma-area product (KAP) and image quality when comparing a 'CQI intervention' group (n = 50) and 'Control' group (n = 50). Visual grading characteristics (VGC) analysis was used to assess image quality, using the 'Control' group as a reference. A significant reduction in KAP by 17% (P = 0.041, d = 0.2) and reference air kerma (Ka, r) by 20% (P = 0.027, d = 0.2) was shown between the two groups. The VGC analysis resulted in an area under the VGC curve (AUCVGC) of 0.54, indicating no significant difference in image quality between the two groups (P = 0.670). The implementation of the CQI program and optimisation of radiation dose parameters improved the UAE radiation dose practices at our centre. The dose reduction demonstrated no detrimental effects on image quality.

The role of quality improvement in radiography

This editorial discusses the importance of quality improvement and quality assurance in the provision of medical imaging services, by exploring two studies which aim to improve the quality of practice in emergency departments (ED). The quality of work by ED radiographers are continually planned, measured, assessed, and improved to enhance patient care outcomes - from the accurate diagnosis of patients, maintaining the consistency of diagnostic images, and to minimising radiation exposure to patients.

Identifying predictors of patient radiation dose during uterine artery embolisation

INTRODUCTION

Uterine artery embolisation (UAE) is regarded as a safe and effective treatment for symptomatic uterine fibroids and/or adenomyosis. Dose reduction during UAE is critical for this reproductive-age patient population to minimise the risks of radiation-induced effects. The aim of this study was to identify the predictors of radiation dose which can be controlled and optimised for patients during UAE.

METHODS

A total of 150 patients between June 2018 and August 2019 were included in this study. Demographic and clinical information such as age, body mass index (BMI), total number of fibroids, total fibroid volume, total uterus volume and dosimetric measurements on Dose Area Product (DAP), Air Kerma (AK) and fluoroscopy time were recorded. Total digital subtraction angiography (DSA), total conventional roadmap (CRM), total last-image hold (LIH) and total fluoroscopy were calculated from the dose report. Multiple linear regression analysis was used to identify the independent predictor variables of total dose (DAP) using a regression model.

RESULTS

Total DSA, total CRM and total LIH were identified as the determinants of dose for UAE (P < 0.05) and together accounted for 95.2% of the variance.

CONCLUSIONS

This study identified the key imaging predictors of dose for UAE. Total DSA, total CRM and total LIH were shown to have a greater impact on the outcome DAP compared to other demographic or dosimetric measurements. Optimisation of these predictors during future UAE procedures can facilitate radiation dose reduction to the pelvis and reproductive organs.

The factors contributing to the total radiation exposure of patients during uterine artery embolisation

Uterine artery embolisation (UAE) is an interventional angiography procedure for the treatment of symptomatic fibroids and/or adenomyosis in women. UAE is a less invasive and non-surgical alternative to hysterectomy or myomectomy. However, ionising radiation is used for both fluoroscopic and angiographic image guidance to visualise and access the uterine arteries for embolisation and treatment of these benign conditions. Identifying the contributors and implementing dose reduction techniques are particularly important as UAE patients are usually of child-bearing age. The purpose of this review was to examine the progression of literature on radiation exposure measurements and identifying the factors contributing to the total radiation exposure of female patients undergoing UAE. A Medline, ProQuest Central, ScienceDirect and Scopus database search from 2000 to 2018 was performed and forty articles were deemed acceptable for review following the inclusion and exclusion criteria set. UAE is a viable alternative to hysterectomy and myomectomy, as the reviewed literature demonstrated that the reported radiation exposure doses appear to be below the threshold for any deterministic radiation risks. The total radiation exposure of UAE patients is affected independently by multiple patient, operator expertise and technique, angiographic imaging and x-ray unit variables. Uterus preservation can be attained post-UAE with dose reduction and optimisation, however, a longitudinal study on UAE patients and their risk of radiation-induced deterministic and/or stochastic effects is recommended.