Computed Tomography Arteriograms (CTA) Volume Dose Reduction Study

• Sponsor: Milton S. Hershey Medical Center (Other)
• Overall Status: Completed
• CT.gov ID: NCT02669784
• Collaborator: (none)
• Enrollment: 34
• Location: 1
• Arms: 2
• Actual Duration (Months): 33
• Patients Per Site Per Month: 1

Study Details

Study Description

Brief Summary

The purpose of the study is to determine if the dose of contrast (Omnipaque) administered for Computed Tomography Arteriograms (CTA) can be reduced without degradation of image quality. The hypothesis is that there is no difference in image quality using ultra-low dose contrast in CTA exams compared to routine, standard of care dose exams.

Condition or Disease	Intervention/Treatment	Phase
Aortic Aneurysm; Contrast Induced Nephropathy; Aortic and Arterial Anomalies	Drug: Low Dose Contrast (Omnipaque) 40mL; Drug: Low Dose Contrast (Omnipaque) 50 mL	N/A

Detailed Description

Any adult patient age 18 and above, scheduled for routine CTA (Computed Tomography Arteriograms) of the chest or chest, abdomen and pelvis meeting inclusion criteria and not meeting any exclusion criteria will be included in the study. The patient will be administered a low dose of intravenous contrast based on the study examination as described below.

CTA of the chest: 40 mL of intravenous contrast (Omnipaque) at a rate of 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds.

CTA of the chest and abdomen or CTA of the chest, abdomen and pelvis: 50 mL of intravenous contrast (Omnipaque) at a rate 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds.

Following the examination, the primary investigator (PI) or team members will evaluate the images obtained with low contrast dose and each patient's prior CTA examination performed with routine contrast dose, 100mL at a rate of 4mL/sec. This will be done by quantitative and qualitative measures. For the quantitative portion, the PI or team members will place regions of interest on predetermined arterial locations to obtain measure the degree of opacification. For qualitative measurement, the images will be presented in a blind fashion to two thoracic trained board certified radiologists and a board certified interventional radiologist to determine the quality of the images based on a Likert numerical scale. Qualitative and quantitative data for the images obtained with low contrast dose and those for the prior CTA examinations performed with routine contrast dose will be compared. This data along with details of the scan protocol (dose, dose rate, scanning parameters etc.) and demographic data (such as sex, age and BMI at the time of examination) will be recorded.

Study Design

• Study Type: Interventional
• Actual Enrollment: 34 participants
• Allocation: Non-Randomized
• Intervention Model: Parallel Assignment
• Masking: None (Open Label)
• Primary Purpose: Other
• Official Title: Does Reduction in Contrast Administration Dose in Computed Tomography Arteriograms Degrade Image Quality? A Single Institutional Review of an Ultra-low Contrast Dose Protocol
• Actual Study Start Date: Feb 1, 2016
• Actual Primary Completion Date: May 1, 2017
• Actual Study Completion Date: Nov 1, 2018

Arms and Interventions

Arm	Intervention/Treatment
Active Comparator: Low Dose Contrast (40mL) CTA of the chest: 40 mL of intravenous contrast at a rate of 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. The Low Dose scan will then be compared to the standard of care high dose scan of the same area taken at a previous date.	Drug: Low Dose Contrast (Omnipaque) 40mL; The patient will be administered a low dose, 40mL of intravenous contrast (Omnipaque) at a rate of 5mL/sec based on the area of the body being scanned (chest versus chest and abdomen versus chest, abdomen and pelvis). This will be compared to the patient's prior examination performed with 100mL of intravenous contrast at a rate of 4mL/sec.
Active Comparator: Low Dose Contrast (50mL) CTA of the abdomen OR or CTA of the chest and abdomen or CTA of the abdomen and pelvis or CTA of the chest, abdomen and pelvis: 50 mL of intravenous contrast at a rate 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. The Low Dose scan will then be compared to the standard of care high dose scan of the same area taken at a previous date.	Drug: Low Dose Contrast (Omnipaque) 50 mL; The patient will be administered a low dose, 50mL of intravenous contrast (Omnipaque) at a rate of 5mL/sec based on the area of the body being scanned (chest versus chest and abdomen versus chest, abdomen and pelvis). This will be compared to the patient's prior examination performed with 100mL of intravenous contrast at a rate of 4mL/sec.

Outcome Measures

Primary Outcome Measures

1. Ascending Sinotubular Junction Measurement [At 30 days]

   Following image acquisition, quantitative analysis was performed by measurement of the attenuation of the contrast bolus by use of Hounsfield Units. Measurement was taken at the ascending aorta near the sinotubular junction.

2. Descending Thoracic Aorta Measurement [30 days]

   Following image acquisition, quantitative analysis was performed by measurement of the attenuation of the contrast bolus by use of Hounsfield Units. A measurement was taken from the distal abdominal aorta prior to the bifurcation.

3. Celiac Measurement [30 days]

   Following image acquisition, quantitative analysis was performed by measurement of the attenuation of the contrast bolus by use of Hounsfield Units. A measurement was taken from the proximal abdominal aorta at the level of the celiac axis.

4. Burfication Measurement [30 days]

   Following image acquisition, quantitative analysis was performed by measurement of the attenuation of the contrast bolus by use of Hounsfield Units. A measurement was taken from the distal abdominal aorta prior to the bifurcation.

5. Right Common Femoral Artery Measurement [30 days]

   Following image acquisition, quantitative analysis was performed by measurement of the attenuation of the contrast bolus by use of Hounsfield Units. A measurement was taken from the right common femoral artery.

6. Left Common Femoral Artery Measurement [30 days]

   Following image acquisition, quantitative analysis was performed by measurement of the attenuation of the contrast bolus by use of Hounsfield Units. A measurement was taken from the right common femoral artery.

7. CTA Vessel Opacification Grading 1 [30 days]

   5 Point Grading Scale was used to determine CTA Vessel Opacification by a Board Certified Radiologist. Poor opacification with no difference in attenuation of the lumen compared to the wall of the vessel. Non diagnostic. Decreased opacification. Little to no difference in attenuation between the lumen and the wall. Non diagnostic. Moderate opacification of the lumen of the vessel. Diagnostic study. Good opacification of the lumen of the vessel. Excellent opacification of the lumen of the vessel with distinct difference in attenuation of the wall and lumen of the vessel.

8. CTA Vessel Opacification Grading 2 [30 days]

   5 Point Grading Scale was used to determine CTA Vessel Opacification by a second Board Certified Radiologist. Poor opacification with no difference in attenuation of the lumen compared to the wall of the vessel. Non diagnostic. Decreased opacification. Little to no difference in attenuation between the lumen and the wall. Non diagnostic. Moderate opacification of the lumen of the vessel. Diagnostic Good opacification of the lumen of the vessel. Excellent opacification of the lumen of the vessel with distinct difference in attenuation of the wall and lumen of the vessel.

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years and Older
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No

Inclusion Criteria:

• Any adult patient scheduled for a computed tomographic arteriogram (CTA) of the chest or chest, abdomen and pelvis who had undergone a prior CTA performed with the standard contrast dose (100 mL) at this institution will be included in the study

• The follow-up scan will be routine standard of care, no emergency imaging patient will be approached for this research

Exclusion Criteria:

• Patients with no prior CTA imaging for comparison

• Any pediatric patient (age <18)

• BMI >40

• Inability to follow instructions

• Allergy to intravenous contrast

• GFR less than 30 mL/min/1.73 m2

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Penn State Milton S. Hershey Medical Center	Hershey	Pennsylvania	United States	17033

Sponsors and Collaborators

• Milton S. Hershey Medical Center

Investigators

None specified.

Study Documents (Full-Text)

• Study Protocol and Statistical Analysis Plan - Nov 16, 2018

More Information

Publications

• Diehm N, Pena C, Benenati JF, Tsoukas AI, Katzen BT. Adequacy of an early arterial phase low-volume contrast protocol in 64-detector computed tomography angiography for aortoiliac aneurysms. J Vasc Surg. 2008 Mar;47(3):492-8. doi: 10.1016/j.jvs.2007.11.004.
• Gleeson TG, Bulugahapitiya S. Contrast-induced nephropathy. AJR Am J Roentgenol. 2004 Dec;183(6):1673-89. Review.
• Gussenhoven MJ, Ravensbergen J, van Bockel JH, Feuth JD, Aarts JC. Renal dysfunction after angiography; a risk factor analysis in patients with peripheral vascular disease. J Cardiovasc Surg (Torino). 1991 Jan-Feb;32(1):81-6.
• Meschi M, Detrenis S, Musini S, Strada E, Savazzi G. Facts and fallacies concerning the prevention of contrast medium-induced nephropathy. Crit Care Med. 2006 Aug;34(8):2060-8. Review.
• Rubin GD. MDCT imaging of the aorta and peripheral vessels. Eur J Radiol. 2003 Mar;45 Suppl 1:S42-9. Review.
• Seehofnerová A, Kok M, Mihl C, Douwes D, Sailer A, Nijssen E, de Haan MJ, Wildberger JE, Das M. Feasibility of low contrast media volume in CT angiography of the aorta. Eur J Radiol Open. 2015 Apr 28;2:58-65. doi: 10.1016/j.ejro.2015.03.001. eCollection 2015.
• Vanommeslaeghe F, De Mulder E, Van de Bruaene C, Van de Bruaene L, Lameire N, Van Biesen W. Selecting a strategy for prevention of contrast-induced nephropathy in clinical practice: an evaluation of different clinical practice guidelines using the AGREE tool. Nephrol Dial Transplant. 2015 Aug;30(8):1300-6. doi: 10.1093/ndt/gfv220. Epub 2015 Jun 4.
• Viteri-Ramírez G, García-Lallana A, Simón-Yarza I, Broncano J, Ferreira M, Pueyo JC, Villanueva A, Bastarrika G. Low radiation and low-contrast dose pulmonary CT angiography: Comparison of 80 kVp/60 ml and 100 kVp/80 ml protocols. Clin Radiol. 2012 Sep;67(9):833-9. doi: 10.1016/j.crad.2011.11.016. Epub 2012 Jun 8.
• Walsh SR, Tang T, Gaunt ME, Boyle JR. Contrast-induced nephropathy. J Endovasc Ther. 2007 Feb;14(1):92-100. Review.
• Wu CC, Lee EW, Suh RD, Levine BS, Barack BM. Pulmonary 64-MDCT angiography with 30 mL of IV contrast material: vascular enhancement and image quality. AJR Am J Roentgenol. 2012 Dec;199(6):1247-51. doi: 10.2214/AJR.12.8739.

• Responsible Party: Rekha Cherian, Physician, Milton S. Hershey Medical Center
• ClinicalTrials.gov Identifier: NCT02669784
• Other Study ID Numbers: 3932
• First Posted: Feb 1, 2016
• Last Update Posted: Jun 11, 2019
• Last Verified: May 1, 2019

• Additional relevant MeSH terms: Aneurysm; Aortic Aneurysm

Study Results

Participant Flow

Arm/Group Title	Contrast (Omnipaque) Low Dose (40mL)	Contrast (Omnipaque) Low Dose (50mL)
Arm/Group Description	CTA of the chest: 40 mL of intravenous contrast (omnipaque) at a rate of 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.	CTA of the chest and abdomen or CTA of the chest, abdomen and pelvis: 50 mL of intravenous contrast at a rate 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.
Period Title: Overall Study
STARTED	18	16
COMPLETED	18	16
NOT COMPLETED	0	0

Baseline Characteristics

Arm/Group Title	Low Dose Contrast (40mL)	Low Dose Contrast (50mL)	Total
Arm/Group Description	CTA of the chest: 40 mL of intravenous contrast at a rate of 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. The Low Dose scan will then be compared to the standard of care high dose scan of the same area taken at a previous date.	CTA of the abdomen OR or CTA of the chest and abdomen or CTA of the abdomen and pelvis or CTA of the chest, abdomen and pelvis: 50 mL of intravenous contrast at a rate 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. The Low Dose scan will then be compared to the standard of care high dose scan of the same area taken at a previous date.	Total of all reporting groups
Overall Participants	18	16	34
Age (Count of Participants)
<=18 years	0 0%	0 0%	0 0%
Between 18 and 65 years	7 38.9%	6 37.5%	13 38.2%
>=65 years	11 61.1%	10 62.5%	21 61.8%
Age (years) [Mean (Full Range) ]
Mean (Full Range) [years]	66	62	66
Sex: Female, Male (Count of Participants)
Female	6 33.3%	5 31.3%	11 32.4%
Male	12 66.7%	11 68.8%	23 67.6%
Race and Ethnicity Not Collected (Count of Participants)
Count of Participants [Participants]	0 0%
Region of Enrollment (participants) [Number]
United States	18 100%	16 100%	34 100%
Type of Scan (Count of Participants)
Chest Scan	17 94.4%	0 0%	17 50%
Abdomen Scan	1 5.6%	0 0%	1 2.9%
Abdomen and Pelvis Scan	0 0%	4 25%	4 11.8%
Chest, Abdomen, and Pelvis Scan	0 0%	11 68.8%	11 32.4%
Chest and Abdomen Scan	0 0%	1 6.3%	1 2.9%
Contrast, 100mL: Scan Dose (Count of Participants)
Count of Participants [Participants]	18 100%	16 100%	34 100%
Contrast, 100mL: Ascending: Sinotubular Junction Measurement (hounsfield units) [Mean (Full Range) ]
Mean (Full Range) [hounsfield units]	317.5	397.6	352.6
Contrast, 100mL: Descending: Pulmonary Artery Measurement (hounsfield units) [Mean (Full Range) ]
Mean (Full Range) [hounsfield units]	283.9	338.1	329
Contrast, 100mL: Celiac Measurement (hounsfield units) [Mean (Full Range) ]
Mean (Full Range) [hounsfield units]	309.1	363.8	334.2
Contrast, 100mL: Bifurcation Measurement (hounsfield units) [Mean (Full Range) ]
Mean (Full Range) [hounsfield units]	322.4	361.4	354.9
Contrast, 100mL: Right Common Femoral Measurement (hounsfield units) [Mean (Full Range) ]
Mean (Full Range) [hounsfield units]	331.3	331	331
Contrast, 100mL: Left Common Femoral Measurement (hounsfield units) [Mean (Full Range) ]
Mean (Full Range) [hounsfield units]	332	350.9	348.5
Contrast, 100mL: CTA Vessel Opacification Grading 1 (score on a scale) [Mean (Full Range) ]
Mean (Full Range) [score on a scale]	4.9	4.7	4.79
Contrast, 100mL: CTA Vessel Opacification Grading 2 (score on a scale) [Mean (Full Range) ]
Mean (Full Range) [score on a scale]	4.8	4.8	4.8

Outcome Measures

1. Primary Outcome

Title	Ascending Sinotubular Junction Measurement
Description	Following image acquisition, quantitative analysis was performed by measurement of the attenuation of the contrast bolus by use of Hounsfield Units. Measurement was taken at the ascending aorta near the sinotubular junction.
Time Frame	At 30 days

Outcome Measure Data

Analysis Population Description

Ascending Sinotubular Junction Measurement was assessed for the following scans: Chest, Abdomen & Pelvis, and Chest, Abdomen, & Pelvis

Arm/Group Title	Contrast (Omnipaque) Low Dose (40mL)	Contrast (Omnipaque) Low Dose (50mL)
Arm/Group Description	CTA of the chest: 40 mL of intravenous contrast (omnipaque) at a rate of 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.	CTA of the chest and abdomen or CTA of the chest, abdomen and pelvis: 50 mL of intravenous contrast at a rate 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.
Measure Participants	17	10
Mean (Full Range) [Hounsfield units]	246.4	287.5

2. Primary Outcome

Title	Descending Thoracic Aorta Measurement
Description	Following image acquisition, quantitative analysis was performed by measurement of the attenuation of the contrast bolus by use of Hounsfield Units. A measurement was taken from the distal abdominal aorta prior to the bifurcation.
Time Frame	30 days

Outcome Measure Data

Analysis Population Description

Descending Thoracic Aorta Measurement was assessed for the following scans: Chest, and Chest, Abdomen, & Pelvis

Arm/Group Title	Contrast (Omnipaque) Low Dose (40mL)	Contrast (Omnipaque) Low Dose (50mL)
Arm/Group Description	CTA of the chest: 40 mL of intravenous contrast (omnipaque) at a rate of 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.	CTA of the chest and abdomen or CTA of the chest, abdomen and pelvis: 50 mL of intravenous contrast at a rate 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.
Measure Participants	17	10
Mean (Full Range) [Hounsfield units]	261.9	312.8

3. Primary Outcome

Title	Celiac Measurement
Description	Following image acquisition, quantitative analysis was performed by measurement of the attenuation of the contrast bolus by use of Hounsfield Units. A measurement was taken from the proximal abdominal aorta at the level of the celiac axis.
Time Frame	30 days

Outcome Measure Data

Analysis Population Description

Celiac Measurement was assessed for all scans: Chest, Abdomen, Abdomen & Pelvis, and Chest, Abdomen, & Pelvis.

Arm/Group Title	Contrast (Omnipaque) Low Dose (40mL)	Contrast (Omnipaque) Low Dose (50mL)
Arm/Group Description	CTA of the chest: 40 mL of intravenous contrast (omnipaque) at a rate of 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.	CTA of the chest and abdomen or CTA of the chest, abdomen and pelvis: 50 mL of intravenous contrast at a rate 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.
Measure Participants	18	16
Mean (Full Range) [Hounsfield units]	243.8	329.5

4. Primary Outcome

Title	Burfication Measurement
Description	Following image acquisition, quantitative analysis was performed by measurement of the attenuation of the contrast bolus by use of Hounsfield Units. A measurement was taken from the distal abdominal aorta prior to the bifurcation.
Time Frame	30 days

Outcome Measure Data

Analysis Population Description

Burfication measurements were taken from the following scans: Abdomen, Abdomen & Pelvis, and Chest, Abdomen, & Pelvis.

Arm/Group Title	Contrast (Omnipaque) Low Dose (40mL)	Contrast (Omnipaque) Low Dose (50mL)
Arm/Group Description	CTA of the chest: 40 mL of intravenous contrast (omnipaque) at a rate of 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.	CTA of the chest and abdomen or CTA of the chest, abdomen and pelvis: 50 mL of intravenous contrast at a rate 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.
Measure Participants	1	16
Mean (Full Range) [Hounsfield units]	336.2	321.2

5. Primary Outcome

Title	Right Common Femoral Artery Measurement
Description	Following image acquisition, quantitative analysis was performed by measurement of the attenuation of the contrast bolus by use of Hounsfield Units. A measurement was taken from the right common femoral artery.
Time Frame	30 days

Outcome Measure Data

Analysis Population Description

All participants in the Contrast (Omnipaque) Low dose (40mL) underwent only a CTA of the chest or abdomen which is incapable of measuring the right common femoral artery.

Arm/Group Title	Contrast (Omnipaque) Low Dose (40mL)	Contrast (Omnipaque) Low Dose (50mL)
Arm/Group Description	CTA of the chest: 40 mL of intravenous contrast (omnipaque) at a rate of 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.	CTA of the chest and abdomen or CTA of the chest, abdomen and pelvis: 50 mL of intravenous contrast at a rate 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.
Measure Participants	0	14
Mean (Full Range) [Hounsfield units]	314.5

6. Primary Outcome

Title	Left Common Femoral Artery Measurement
Description	Following image acquisition, quantitative analysis was performed by measurement of the attenuation of the contrast bolus by use of Hounsfield Units. A measurement was taken from the right common femoral artery.
Time Frame	30 days

Outcome Measure Data

Analysis Population Description

All participants in the Contrast (Omnipaque) Low dose (40mL) underwent only a CTA of the chest or abdomen which is incapable of measuring the Left common femoral artery

Arm/Group Title	Contrast (Omnipaque) Low Dose (40mL)	Contrast (Omnipaque) Low Dose (50mL)
Arm/Group Description	CTA of the chest: 40 mL of intravenous contrast (omnipaque) at a rate of 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.	CTA of the chest and abdomen or CTA of the chest, abdomen and pelvis: 50 mL of intravenous contrast at a rate 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.
Measure Participants	0	14
Mean (Full Range) [Hounsfield units]	309.5

7. Primary Outcome

Title	CTA Vessel Opacification Grading 1
Description	5 Point Grading Scale was used to determine CTA Vessel Opacification by a Board Certified Radiologist. Poor opacification with no difference in attenuation of the lumen compared to the wall of the vessel. Non diagnostic. Decreased opacification. Little to no difference in attenuation between the lumen and the wall. Non diagnostic. Moderate opacification of the lumen of the vessel. Diagnostic study. Good opacification of the lumen of the vessel. Excellent opacification of the lumen of the vessel with distinct difference in attenuation of the wall and lumen of the vessel.
Time Frame	30 days

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Contrast (Omnipaque) Low Dose (40mL)	Contrast (Omnipaque) Low Dose (50mL)
Arm/Group Description	CTA of the chest: 40 mL of intravenous contrast (omnipaque) at a rate of 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.	CTA of the chest and abdomen or CTA of the chest, abdomen and pelvis: 50 mL of intravenous contrast at a rate 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.
Measure Participants	18	16
Mean (Full Range) [score on a scale]	4	4.3

8. Primary Outcome

Title	CTA Vessel Opacification Grading 2
Description	5 Point Grading Scale was used to determine CTA Vessel Opacification by a second Board Certified Radiologist. Poor opacification with no difference in attenuation of the lumen compared to the wall of the vessel. Non diagnostic. Decreased opacification. Little to no difference in attenuation between the lumen and the wall. Non diagnostic. Moderate opacification of the lumen of the vessel. Diagnostic Good opacification of the lumen of the vessel. Excellent opacification of the lumen of the vessel with distinct difference in attenuation of the wall and lumen of the vessel.
Time Frame	30 days

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Contrast (Omnipaque) Low Dose (40mL)	Contrast (Omnipaque) Low Dose (50mL)
Arm/Group Description	CTA of the chest: 40 mL of intravenous contrast (omnipaque) at a rate of 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.	CTA of the chest and abdomen or CTA of the chest, abdomen and pelvis: 50 mL of intravenous contrast at a rate 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. This will be compared to the patient's prior examination performed with 100 mL of intravenous contrast.
Measure Participants	18	16
Mean (Full Range) [score on a scale]	4.2	4.4

Adverse Events

Time Frame	30 days
Arm/Group Title	Low Dose Contrast (40mL)		Low Dose Contrast (50mL)
Arm/Group Description	CTA of the chest: 40 mL of intravenous contrast (omnipaque) at a rate of 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. . The Low Dose scan will then be compared to the standard of care high dose scan of the same area taken at a previous date.		CTA of the chest and abdomen or CTA of the chest, abdomen and pelvis: 50 mL of intravenous contrast at a rate 5mL/sec. A region of interest (ROI) to trigger the scan will be placed in the aortic arch. If scan is performed using high pitch helical mode, the scan delay will be increased by 2 seconds. The Low Dose scan will then be compared to the standard of care high dose scan of the same area taken at a previous date.
All Cause Mortality
	Low Dose Contrast (40mL)		Low Dose Contrast (50mL)
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/18 (0%)		0/16 (0%)
Serious Adverse Events
	Low Dose Contrast (40mL)		Low Dose Contrast (50mL)
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/18 (0%)		0/16 (0%)
Other (Not Including Serious) Adverse Events
	Low Dose Contrast (40mL)		Low Dose Contrast (50mL)
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/18 (0%)		0/16 (0%)

Limitations/Caveats

[Not Specified]

More Information

Certain Agreements

All Principal Investigators ARE employed by the organization sponsoring the study.

There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.