Authors (including presenting author) :
KWOK HM(1), PAN NY(1)
Affiliation :
(1) Department of Diagnostic and Interventional Radiology, Princess Margaret Hospital, Kowloon West Cluster
Introduction :
VCU remained the gold standard for the evaluation of vesicoureteric reflux (VUR), providing both anatomical and functional evaluation. Besides VUR, it also provides evaluation to the bladder and urethra. Radiographic findings provide lots of prognosticative information besides grading in guiding individualized management.
Variation about VCU techniques and reporting qualities does not allow valid comparison of data between individuals and institution1.
To improve patient safety and to standardize the data obtained, the American Academy of Pediatrics (AAP) Section on Radiology and the AAP Section on Urology created consensus (2016) on how to perform this test1. The techniques and image adequacy are in line with those suggested by the guideline published jointly by the American Society of Radiology (ACR) and Society of Pediatric Radiology (SPR) (2019), and the SPR Safety, Quality of Care, Practice Guidelines.
It is important to strike a balance between image quality and radiation dose in order to achieve “As Low As Reasonably Achievable” (ALARA)1. The International Commission on Radiological Protection (ICRP) published diagnostic reference level regarding VCU in pediatric population5. It was stated that variation in patient radiation dose due to incorrect technique is not appropriate. The image quality should be evaluated as part of Diagnostic Reference Level (DRL) process in order to achieve optimization.
On this ground, we aim this audit would optimize both image techniques and radiation dose in pediatric population. And standardized reporting would yield invaluable diagnostic information to facilitate individualized treatment in patients with VUR.
Objectives :
1. To evaluate how close we perform against international standards regarding MCU image adequacy, standard reporting and radiation dose.
2. To optimize both image techniques and radiation dose of MCU in the pediatric population
3. To standardize reporting items in order to facilitate individualized treatment of VUR within and across institutions.
Methodology :
A total of 35 cases were identified from the Radiology Information System (RIS) from 1 Jan 2019 to 30 Jun 2020 (inclusive) (18 months) including age range from 0-18 years old. Failed cases or incomplete exam (n = 3) were excluded. Image adequacy, number of cycles performed and reporting items are evaluated after reviewing the images and reports. Mean dose-area-product (DAP) were calculated and evaluated against international reference from ICRP.
Internation Standard:
1. For image adequacy and structured reporting, we aim 100% of our cases reaching the standard.
2. For radiation dose, the mean DRL of the study population should fall below that of UK DRL
Image Adequacy
1. Pulsed fluoroscopy, last image hold, and fluoroscopic image capture result in reduced radiation dose and should be used.
2. The use of more than 1 bladder filling is a common standard.
3. Prelimary fluoroscopic grab image can be obtained to review osseous structures. If there is abdominal radiograph in preceding 3-6 months available, then it can be omitted.
4. Early-filling last-image capture of the bladder with a small amount of contrast may reveal an intravesical ureterocele or other mass, which might be obscured by larger contrast volume. While further bladder filling occurs, continuous imaging is not necessary.
5. Oblique radiographs of the bladder are obtained when the bladder is estimated to be full, prior to voiding to profile each ureterovesical junction in relation to the bladder neck.
6. Voiding phase image should include the entire urethra. In male, oblique images should be obtained. In girls, the urethra is generally imaged in the frontal projection.
7. Post-void images of the renal fossae obtained to document the presence and grade of reflux or its absence.
Standard Reporting
1. Record number of cycle performed and maximal amount of contrast instilled.
2. Record any osseous abnormality detected on scout image
3. Record any VUR detected
4. Record phase of study in which VUR first detected.
5. Record highest grading of VUR detected according to International Reflux Study.
6. Record insertion of refluxing ureter.
7. Record volume of residual bladder contrast post-void
8. Record bladder outline
9. Record any filling defect within urinary bladder
10. Record any abnormal dilatation or stricture of urethra.
Radiation Dose
1. The mean DRL of the study population fall below that of United Kingdom (UK) DRL of similar age group
Result & Outcome :
For the image quality, 88% (n=28) have taken scout image, 91% (n=29) have taken anteroposterior (AP) bladder early filling view, 25% (n=8) have taken oblique view, 84% (n=27) have taken satisfactory voiding view. 75% (n=24) have taken AP view of bilateral renal fossa post-void and 97% (n=31) have taken AP view of bladder post-void.
43.8% of the cases (n=14) performed 1 cycle only.
For the reporting 0% reporting osseous abnormality and 23% (n=7) report any opaque calculi on scout image. 100 (n=32) reported any VUR. Among the 12 cases with positive VUR, 8% (n=1) reported the phase of onset of VUR, with 17% (n=2) reported earliest onset of VUR and 100% reported the highest VUR grading, but 0% reported the insertion of refluxing ureter. 100% reported the bladder outline and 60% (n=19) reported any intravesical filling defect. 15.6% (n=5) reported volume of contrast instilled and 34% (n=11) reported residual bladder contrast post-void. 91% (n=29) reported urethra appearance.
For the 0-1 year-old group (N=18), the mean DRL is 0.12 Gycm2 which is higher than that of UK DRL (0.1 Gycm2). For the 1-5 year-old group mean DRL 0.14 Gycm2 (n=11) and that for 5-10 year-old group 0.37 Gycm2 (n=3) is lower than that of the UK DRL (0.3Gycm2 and 0.4Gycm2 respectively).
Implementation action plan:
1. Departmental staff meeting for discussion of results
2. Education lecture to trainees
3. Poster for recommended images available in the fluoroscopic room.
4. Departmental reporting template in Radiology Information System.
5. Individual coaching and supervision on each cases.
(Second cycle data are in progress and detailed data will be included in presentation. Prelimary data showed significant improvement of the image adequacy and reporting standards following the international standards. Mean DRL of the study population significantly improved).
