Optimising Paediatric Trauma and Split-Bolus Contrast ...Optimising Paediatric Trauma and...
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Optimising Paediatric Trauma and Split-Bolus Contrast-Enhanced CT Examinations Author: Barbara Nugent DCR(R), PgC, BSc (Hons) MRI & CT Superintendent Radiographer, Royal Hospital for Sick Children, Edinburgh Acknowledgements: Dr Moti Chowdhury & Dr Jeremy B Jones Consultant Paediatric Radiologists, Royal Hospital for Sick Children, Edinburgh Introduction and Background Contrast enhanced (CE) CT is vital for evaluating injuries and abnormalities. Tissue enhancement is visualised through the multi-phases of blood flow (arterial, parenchymal, portal-venous and venous). A split-bolus of contrast (2 volumes of iodine based X-ray dye) is pumped and scans performed to ‘catch’ contrast as it travels through the body using a multi-slice CT scanner (MSCT). However patients may be scanned twice to highlight correct phases, exposing them to double the radiation. This is a significant concern in paediatric scanning as children are more vulnerable to radiation effects (1) . Using a different technique we could scan a region of interest (ROI) once and still achieve dual/triple-phase enhancement (2) . As a CT radiographer working in a children’s hospital I sought to develop a more appropriate protocol. Camp Bastion Protocol (CBP) - currently promoted for all ages CBP (3, 4) aids diagnosis of acute adult blast injuries, image quality is acceptable for battlefield scanning and the ROI is scanned once. But, contrast volumes, flow rates and ROI’s scanned do not maximise parameters required for quality paediatric scanning. However, the protocol is routinely promoted for dynamic enhancement for all ages and a weight based contrast ‘wheel’ (figure 1) is used. CT scan commences at 70 sec. from initial injection, irrespective of individual arterial/venous flow rates. Pitfalls of CBP for Paediatric Imaging Blood circulation times vary (for children, 20-25 sec. arterial, and 45-65 sec. venous), so scanning at 70 sec. may be too late. Density of iodine at low flow rates also means minimum enhancement. CBP, though, is of benefit in departments that only have a single headed injector. For general and especially dedicated paediatric departments, with a dual headed system, this protocol is suboptimal for image quality and ROI’s scanned. Children are subjected to an examination which, in the vast majority of cases, is inappropriate and substandard. It does not fully compensate for increased blood flow rates or utilise best scanning parameters. 10Kg Patient 20ml contrast: 14ml @ 0.3ml/sec 7ml @ 0.6ml/sec 20Kg Patient 40ml contrast: 26ml @ 0.5ml/sec 14ml @ 1.0ml/sec 30Kg Patient 60ml contrast: 40ml @ 0.7ml/sec 20ml @ 1.6ml/sec 40Kg Patient 80ml contrast: 54ml @ 0.9ml/sec 26ml @ 2.1ml/sec 50Kg Patient 100ml contrast: 66ml @ 1.2ml/sec 34ml @ 2.4ml/sec 60Kg Patient 120ml contrast: 80ml @ 1.4ml/sec 40ml @ 2.8ml/sec 70Kg Patient 140ml contrast: 94ml @ 1.6ml/sec 46ml @ 3.3ml/sec 75Kg Patient 150ml contrast: 100ml @ 1.6ml/sec 50ml @ 3.5ml/sec Figure 1 Camp Bastion Contrast Calculator Wheel Biphasic Injection Protocol in Trauma CT New Method for Paediatric CE Imaging - RHSC Trauma/Split-Bolus Protocol Best enhancement is achieved if patient weight and appropriate flow rates (5) are considered along with scanning parameters. Consequently a CT protocol (image 1), data tables (tables 1 & 2) and pre-set pump parameters (image 2) have been devised. Now pre-calculated specific contrast volumes and scan initiation times are available. These reflect more accurately the expected arterial or venous enhancement times (images 3, 4 & 5). Weight of Patient Total volume of contrast 2mls/kg Flow rate/sec 1 st contrast bolus volume (total volume halved) Pause Time 2 nd contrast bolus volume Time into saline flush when CT scan started Time to start CT scan 5kg 10mls 1.5mls/sec 5mls 24sec 5mls 17sec 47sec 10kg 20mls 1.5mls/sec 10mls 26sec 10mls 14sec 52sec 10kg 20mls 2mls/sec 10mls 35sec 10mls 15sec 60sec 15kg 30mls 2mls/sec 15mls 25sec 15mls 18sec 57sec 20kg 40mls 2mls/sec 20mls 30sec 20mls 15sec 65sec 25kg 50mls 2mls/sec 25mls 30sec 25mls 8sec 62sec 30kg 60mls 2mls/sec 30mls 25sec 30mls 10sec 65sec 35kg 70mls 2mls/sec 35mls 22.5sec 35mls 8sec 64.5sec 40kg 80mls 2mls/sec 40mls 20sec 40mls 5sec 65sec 50kg 100mls 2.5mls/sec 50mls 20sec 50mls 5sec 65sec 60kg 100mls 3mls/sec 50mls 23sec 50mls 8sec 65sec RHSC Contrast Calculator Table - Delay Times & Flow Rates According to Weight for Trauma/Split-Bolus Enhancement Table 1 Weight of Patient Total volume of contrast 2mls/kg Flow rate/sec 1 st contrast bolus volume (total volume halved) Time of 1 st bolus injection at flow rate chosen (A) Pause Time (B) Cumulative time of A + B 2 nd contrast bolus volume (C) Time of 2nd bolus injection (D) Total time of both contrast injections + pause time A + B + D Time into saline flush when CT scan started (E) Time of arterial phase (2 nd bolus + flush) D + E Time of venous phase (1 st bolus + pause + 2 nd bolus + flush) A + B + D + E 5kg 10mls 1.5mls/ sec 5mls 3sec 24sec 27sec 5mls 3sec 30sec 17sec 20sec 47sec 10kg 20mls 1.5mls/ sec 10mls 6sec 26sec 32sec 10mls 6sec 38sec 14sec 20sec 52sec 10kg 20mls 2mls/sec 10mls 5sec 35sec 40sec 10mls 5sec 45sec 15sec 20sec 60sec 15kg 30mls 2mls/sec 15mls 7sec 25sec 32sec 15mls 7sec 39sec 18sec 25sec 57sec 20kg 40mls 2mls/sec 20mls 10sec 30sec 40sec 20mls 10sec 50sec 15sec 25sec 65sec 25kg 50mls 2mls/sec 25mls 12sec 30sec 42sec 25mls 12sec 54sec 8sec 20sec 62sec 30kg 60mls 2mls/sec 30mls 15sec 25sec 40sec 30mls 15sec 55sec 10sec 25sec 65sec 35kg 70mls 2mls/sec 35mls 17sec 22.5sec 39.5sec 35mls 17sec 56.5sec 8sec 25sec 64.5sec 40kg 80mls 2mls/sec 40mls 20sec 20sec 40sec 40mls 20sec 60sec 5sec 25sec 65sec 50kg 100mls 2.5mls/ sec 50mls 20sec 20sec 40sec 50mls 20sec 60sec 5sec 25sec 65sec 60kg 100mls 3mls/sec 50mls 17sec 23sec 40sec 50mls 17sec 57sec 8sec 25sec 65sec Working out of Delay Times & Flow Rates for Trauma/ Split-Bolus Enhancement Table 2 Image 5 Image 3 Image 4 Image 1 Image 2 Training Training material has been devised to improve scanning confidence in performing a complex examination in often stressful circumstances, complemented by use of a test ‘phantom’ and multi-use syringes (image 6). Conclusion A more appropriate alternative to the CBP can be performed by utilising accurate circulation times. Pre-programmed CT protocols and pump factors ensure appropriate ROI’s and scanning parameters are used, maximising image quality and facilitating best practice for all ages but particularly for paediatric patients. The increased contrast density improves enhancement and diagnosis (5, 6) . An added bonus is that contrast is not wasted on patients under certain weights. RHSC technique can be used on any MSCT scanner and the table data can be pre-programmed into any dual-headed syringe pump console (image 7) maximising their capabilities. Image 6 Image 7 References 1) Nievelstein Rutger AJ, van Dam Ingrid M, van der Molen Aart J, Multidetector CT in children: current concepts and dose reduction strategies: Pediatr Radiol (2010) 40:1324-1344 2) Yaniv G, Portnoy O, Simon D, Bader S, Konen E, Guranda L, Revised protocol for whole-body CT for multi-trauma patients applying triphasic injection followed by a single-pass on a 64-MDCT: Clin Radiol, 2013 Jul,68(7) 668-75 3) Graham RNJ, Battlefield Radiology: BJ Radiol. Dec2012; 85 (1020): 1556-1565 4) Nguyen D, Platon A, Shanmuganathan K, Mirvis S, Becker CD, Poletti PA, Evaluation of a Single-Pass Continuous Whole- Body16-MDCT Protocol for Patients with polytrauma: American J of Roentgenology, 2009; 192:3-10 5) Peng Hui Lee, Optimising contrast enhancement in abdominal CT: RAD Magazine, 35,414,17,18 6) Schoellnast H,Brader P, Oberdabernig B, Pisail B, Deutschmann H, Fritz G, Schaffler, G, Tillich M, High-Concentration Contrast Media in Multiphasic Abdominal Multidetector-Row Computed Tomography: J Comput Tomog Vol 29, No 5, September/October 2005 Scan protocol: 2/3 contrast volume injected at slow rate x, and 1/3 volume injected at approximately 2x. Contrast rates are calculated for injection phase to last 70 secs. Scan initiated at 70 seconds. Ref: Medical Photography Service, St John’s Hospital - August 2014 Ascending Aorta Pulmonary Trunk Descending Aorta Portal Vein Abdominal Aorta Hepatic IVC Portal Vein Hepatic Artery Iliac Vein Pre-Programmed Trauma Protocol on CT Console Pre-Programmed Pump Programme Arterial & Venous Enhancement Displayed Using the Split-Bolus Protocol Arterial & Venous Enhancement Displayed Using the Split-Bolus Protocol Dual Phase Enhancement for Liver Mass using Split-Bolus Protocol
Transcript of Optimising Paediatric Trauma and Split-Bolus Contrast ...Optimising Paediatric Trauma and...
Optimising Paediatric Trauma and Split-Bolus Contrast-Enhanced CT Examinations
Author: Barbara Nugent DCR(R), PgC, BSc (Hons) MRI & CT Superintendent Radiographer, Royal Hospital for Sick Children, EdinburghAcknowledgements: Dr Moti Chowdhury & Dr Jeremy B Jones Consultant Paediatric Radiologists, Royal Hospital for Sick Children, Edinburgh
Introduction and BackgroundContrast enhanced (CE) CT is vital for evaluating injuries and abnormalities. Tissue enhancement is visualised through the multi-phases of blood flow (arterial, parenchymal, portal-venous and venous). A split-bolus of contrast (2 volumes of iodine based X-ray dye) is pumped and scans performed to ‘catch’ contrast as it travels through the body using a multi-slice CT scanner (MSCT). However patients may be scanned twice to highlight correct phases, exposing them to double the radiation. This is a significant concern in paediatric scanning as children are more vulnerable to radiation effects(1). Using a different technique we could scan a region of interest (ROI) once and still achieve dual/triple-phase enhancement(2). As a CT radiographer working in a children’s hospital I sought to develop a more appropriate protocol.
Camp Bastion Protocol (CBP) - currently promoted for all agesCBP(3, 4) aids diagnosis of acute adult blast injuries, image quality is acceptable for battlefield scanning and the ROI is scanned once. But, contrast volumes, flow rates and ROI’s scanned do not maximise parameters required for quality paediatric scanning. However, the protocol is routinely promoted for dynamic enhancement for all ages and a weight based contrast ‘wheel’ (figure 1) is used. CT scan commences at 70 sec. from initial injection, irrespective of individual arterial/venous flow rates.
Pitfalls of CBP for Paediatric ImagingBlood circulation times vary (for children, 20-25 sec. arterial, and 45-65 sec. venous), so scanning at 70 sec. may be too late. Density of iodine at low flow rates also means minimum enhancement. CBP, though, is of benefit in departments that only have a single headed injector. For general and especially dedicated paediatric departments, with a dual headed system, this protocol is suboptimal for image quality and ROI’s scanned. Children are subjected to an examination which, in the vast majority of cases, is inappropriate and substandard. It does not fully compensate for increased blood flow rates or utilise best scanning parameters.
10Kg Patient20ml contrast:14ml @ 0.3ml/sec7ml @ 0.6ml/sec
20Kg Patient40ml contrast:26ml @ 0.5ml/sec14ml @ 1.0ml/sec
30Kg Patient60ml contrast:40ml @ 0.7ml/sec20ml @ 1.6ml/sec
40Kg Patient80ml contrast:54ml @ 0.9ml/sec26ml @ 2.1ml/sec
50Kg Patient100ml contrast:66ml @ 1.2ml/sec34ml @ 2.4ml/sec
60Kg Patient120ml contrast:80ml @ 1.4ml/sec40ml @ 2.8ml/sec
70Kg Patient140ml contrast:94ml @ 1.6ml/sec46ml @ 3.3ml/sec
75Kg Patient150ml contrast:100ml @ 1.6ml/sec50ml @ 3.5ml/sec
Figure 1
Camp Bastion Contrast Calculator WheelBiphasic Injection Protocol in Trauma CT
New Method for Paediatric CE Imaging - RHSC Trauma/Split-Bolus ProtocolBest enhancement is achieved if patient weight and appropriate flow rates(5) are considered along with scanning parameters. Consequently a CT protocol (image 1), data tables (tables 1 & 2) and pre-set pump parameters (image 2) have been devised. Now pre-calculated specific contrast volumes and scan initiation times are available. These reflect more accurately the expected arterial or venous enhancement times (images 3, 4 & 5).
Weight of Patient Total volume of contrast 2mls/kg
Flow rate/sec 1st contrast bolus volume (total volume halved)
Pause Time 2nd contrast bolus volume Time into saline flush when CT scan started
Time to start CT scan
5kg 10mls 1.5mls/sec 5mls 24sec 5mls 17sec 47sec10kg 20mls 1.5mls/sec 10mls 26sec 10mls 14sec 52sec10kg 20mls 2mls/sec 10mls 35sec 10mls 15sec 60sec15kg 30mls 2mls/sec 15mls 25sec 15mls 18sec 57sec20kg 40mls 2mls/sec 20mls 30sec 20mls 15sec 65sec25kg 50mls 2mls/sec 25mls 30sec 25mls 8sec 62sec30kg 60mls 2mls/sec 30mls 25sec 30mls 10sec 65sec35kg 70mls 2mls/sec 35mls 22.5sec 35mls 8sec 64.5sec40kg 80mls 2mls/sec 40mls 20sec 40mls 5sec 65sec50kg 100mls 2.5mls/sec 50mls 20sec 50mls 5sec 65sec60kg 100mls 3mls/sec 50mls 23sec 50mls 8sec 65sec
RHSC Contrast Calculator Table - Delay Times & Flow Rates According to Weight for Trauma/Split-Bolus Enhancement
Table 1
Weight of Patient
Total volume of contrast
2mls/kg
Flow rate/sec
1st contrast bolus volume
(total volume halved)
Time of 1st bolus injection at flow
rate chosen (A)
Pause Time(B)
Cumulative time of A + B
2nd contrast bolus volume
(C)
Time of 2nd bolus injection
(D)
Total time of both contrast injections
+ pause time A + B + D
Time into saline flush when CT scan started
(E)
Time of arterial phase (2nd bolus +
flush)D + E
Time of venous phase (1st bolus + pause + 2nd
bolus + flush) A + B + D + E
5kg 10mls 1.5mls/sec
5mls 3sec 24sec 27sec 5mls 3sec 30sec 17sec 20sec 47sec
10kg 20mls 1.5mls/sec
10mls 6sec 26sec 32sec 10mls 6sec 38sec 14sec 20sec 52sec
10kg 20mls 2mls/sec 10mls 5sec 35sec 40sec 10mls 5sec 45sec 15sec 20sec 60sec15kg 30mls 2mls/sec 15mls 7sec 25sec 32sec 15mls 7sec 39sec 18sec 25sec 57sec20kg 40mls 2mls/sec 20mls 10sec 30sec 40sec 20mls 10sec 50sec 15sec 25sec 65sec25kg 50mls 2mls/sec 25mls 12sec 30sec 42sec 25mls 12sec 54sec 8sec 20sec 62sec30kg 60mls 2mls/sec 30mls 15sec 25sec 40sec 30mls 15sec 55sec 10sec 25sec 65sec35kg 70mls 2mls/sec 35mls 17sec 22.5sec 39.5sec 35mls 17sec 56.5sec 8sec 25sec 64.5sec40kg 80mls 2mls/sec 40mls 20sec 20sec 40sec 40mls 20sec 60sec 5sec 25sec 65sec50kg 100mls 2.5mls/
sec50mls 20sec 20sec 40sec 50mls 20sec 60sec 5sec 25sec 65sec
60kg 100mls 3mls/sec 50mls 17sec 23sec 40sec 50mls 17sec 57sec 8sec 25sec 65sec
Working out of Delay Times & Flow Rates for Trauma/ Split-Bolus Enhancement
Table 2
Image 5
Image 3 Image 4
Image 1 Image 2
TrainingTraining material has been devised to improve scanning confidence in performing a complex examination in often stressful circumstances, complemented by use of a test ‘phantom’ and multi-use syringes (image 6).
ConclusionA more appropriate alternative to the CBP can be performed by utilising accurate circulation times. Pre-programmed CT protocols and pump factors ensure appropriate ROI’s and scanning parameters are used, maximising image quality and facilitating best practice for all ages but particularly for paediatric patients. The increased contrast density improves enhancement and diagnosis(5, 6). An added bonus is that contrast is not wasted on patients under certain weights. RHSC technique can be used on any MSCT scanner and the table data can be pre-programmed into any dual-headed syringe pump console (image 7) maximising their capabilities.
Image 6 Image 7
References1) Nievelstein Rutger AJ, van Dam Ingrid M, van der Molen Aart J, Multidetector CT in children: current concepts and dose reduction strategies: Pediatr Radiol (2010) 40:1324-13442) Yaniv G, Portnoy O, Simon D, Bader S, Konen E, Guranda L, Revised protocol for whole-body CT for multi-trauma patients applying triphasic injection followed by a single-pass on a 64-MDCT: Clin Radiol, 2013 Jul,68(7) 668-753) Graham RNJ, Battlefield Radiology: BJ Radiol. Dec2012; 85 (1020): 1556-15654) Nguyen D, Platon A, Shanmuganathan K, Mirvis S, Becker CD, Poletti PA, Evaluation of a Single-Pass Continuous Whole- Body16-MDCT Protocol for Patients with polytrauma: American J of Roentgenology, 2009; 192:3-105) Peng Hui Lee, Optimising contrast enhancement in abdominal CT: RAD Magazine, 35,414,17,186) Schoellnast H,Brader P, Oberdabernig B, Pisail B, Deutschmann H, Fritz G, Schaffler, G, Tillich M, High-Concentration Contrast Media in Multiphasic Abdominal Multidetector-Row Computed Tomography: J Comput Tomog Vol 29, No 5, September/October 2005
Scan protocol:2/3 contrast volume injected at slow rate x, and 1/3 volume injected at approximately 2x. Contrast rates are calculated for injection phase to last 70 secs. Scan initiated at 70 seconds.
Ref: Medical Photography Service, St John’s Hospital - August 2014
Ascending AortaPulmonary Trunk
Descending Aorta
Portal Vein
Abdominal Aorta
Hepatic IVC
Portal VeinHepatic Artery
Iliac Vein
Pre-Programmed Trauma Protocol on CT Console Pre-Programmed Pump Programme
Arterial & Venous Enhancement Displayed Using the Split-Bolus Protocol Arterial & Venous Enhancement Displayed Using the Split-Bolus Protocol
Dual Phase Enhancement for Liver Mass using Split-Bolus Protocol
