CT Scanning and Injection Protocols

More than 600 clinical cases have been processed using the AngioVis setup. The generation of MIPs, and various forms of Curved Planar Reformations has been used clinically at the Department of Cardiovascular and Interventional Radiology, Medical University of Vienna, Austria, using a 16-channel Multislice CT scanner. Recently, we have been using a 64-slice scanner at Medical University of Vienna, Austria and at Stanford University, USA.

The axial CT source images are transferred to the AngioVis workstation, where post-processing steps are performed by experienced CT technologists. The resulting images are sent to PACS (in DICOM format), and are then reviewed by the radiologist and vascular surgeons on any PACS viewing station.

Routine readout usually begins with looking at the MIP images, as they give an "angiography-like" overview. In the presence of vessel calcifications or endoluminal stents, the assessment of the flow channel requires the analysis of cross-sectional images. The most comprehensive tool to read cross sections is to use multi-path curved planar reformations. In many instances, these images provide the necessary clinical information. If necessary, the user can also read single-path CPRs through a vessel of interest. As all images are read on PACS workstations, all images can be magnified (zoom), and the viewing window settings can be altered interactively. This is crucial in the presence of calcifications/stents because too narrow window settings may cause –pseudo-stenosis due to the blooming artifact.

The following section describes our current scanning technique, the technique of contrast medium injection, and the routine post-processing steps for visualizing peripheral arterial occlusive disease for diagnosis and treatment planning, using the AngioVis programs.

Recent clinical examples with angiographic correlation will be available for practical testing at the exhibition booth.

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Department of Radiology
Stanford University Medical Center
Stanford, CA  - USA
D. Fleischmann

Lower Extremities Runoff
Scanning Protocol – Siemens S 64

Scan protocol	RUNOFF (Vascular Folder)
Topogram	1500 mm AP; feet first, arms up; feet still and relaxed; support with cushions/tape;
Range 1+2	Bolus Tracking, ROI in abdominal aorta at celiac artery
Range 3	Runoff: from above the celiac trunk (D12 vertebral body) through toes 120kV / Care dose 4D w. 250 ref-mAs) 64x0.6mm, 0.5s gantry-rotation 40s scantime for all patients! (NOTE: this will result in a pitch<1), ! Set scanrange first, then change scantime to 40s !
Range 4	Runoff: Pre-programmed optional second CTA acquisition to cover popliteal and crural territories. This range is only initiated, if there is no contrast medium opacification seen in the popliteal/crural vascular territories; If distal arterial opacification is adequate, just cut (delete) Range 4
Breathhold	at inspiration
Scandirection	cranio-caudal
Injection Protocol	20-22G  IV line,  Isovue (iopamidol) 370 Bolus tracking with ROI in Abdominal Aorta (beginning of scan range). Minimum delay (3s including automated breath-hold-command) Use a biphasic injection protocol with 35s injection duration Injection Rates and Volumes (adjusted to patient size)   ~BW VOL1  Flow1 VOL2 Flow2 (kg) (mL) (mL/s) (mL) (mL/s) XS <55kg 20 4 96 3.2 S <65kg 23 4.5 108 3.6 average 75kg 25 5 120 4 L >85kg 28 5.5 132 4.4 XL >95kg 30 6 144 4.8           Saline flush: 40mL volume, flow-rate equal to 'Flow2'
Reconstruction (STh/RI)	Range 3: 2/1 B25f  (patients w. Fontain IIb) FoV: to greater trochanter 1/0.7 B25f  (patients w. Fontain III/IV) 5/5  B31f  Abd/Pelvis only ! Range 4: 1/0.7 B25f
Transfer	Auto transfer of all data to PACS Transfer to ANGIOVIS workstation

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Department of Cardiovascular and Interventional Radiology
Medical University of Vienna
Vienna, Austria
J. Lammer

Lower Extremities Runoff
Scanning Protocol – Philips Brilliance 64

Indication	Peripheral arterial occlusive disease
Scanprotocol	(Vascular Folder)
Topogram	1500 mm AP; feet first, arms up; feet still and relaxed; support with cushions/tape;
Range 1+2	Bolus Tracking, ROI in abd. aorta at celiac artery
Range 3	Runoff: from above the celiac artery (D12 vertebral body) through toes 120kV / 180 eff.mAs 64 x 0.625mm 0.75s gantry-rotation pitch 0.7 - 0.8
Range 4	Runoff: Pre-programmed optional second CTA acquisition to cover popliteal and crural territories. This range is only initiated, if there is no contrast medium opacification seen in the popliteal/crural vascular territories; If distal arterial opacification is adequate, just cut (delete) Range 4
Breathhold	at inspiration
Scandirection	cranio-caudal
Injection Protocol	17-20G  IV line,  Iomeron (iomeprol) 400 Bolus tracking with ROI in abdominal aorta (beginning of scan range); minimum delay (4s including automated breath-hold-command). Biphasic injection protocol Volume 1 = 25 mL,     injected at 4.5 mL/s Volume 2 =  58 mL for PAOD II&III, 68mL for PAOD IV Saline flush: 40mL volume, flow rate 2.3 mL/s
Reconstruction	1.5 / 0.75 mm
Transfer	Auto transfer of all data to PACS & to ANGIOVIS workstation

Lower Extremities Runoff
Scanning Protocol – Siemens S16

Indication	Peripheral arterial occlusive disease
Scanprotocol	RUNOFF (Vascular Folder)
Topogram	1500 mm AP; feet first, arms up; feet still and relaxed; support with cushions/tape;
Range 1+2	Bolus Tracking, ROI in abd. aorta at celiac artery
Range 3	Runoff: from above the celiac artery (D12 vertebral body) through toes 120kV / 130 eff.mAs 16 x 0.75mm 0.5s gantry-rotation Table-feed ~14mm/s  (scantime is ~ 45– 55s)
Breathhold	at inspiration
Scandirection	cranio-caudal
Injection Protocol	17-20G  IV line,  Iomeron (iomeprol) 400 Bolus tracking with ROI in abdominal aorta (beginning of scan range); minimum delay (3s including automated breath-hold-command). Biphasic injection protocol Volume 1 = 25 mL, injected at 4.5 mL/s Volume 2 =  __ mL* injected at 2.3 mL/s Saline flush: 40mL volume, flow rate 2.3 mL/s
Reconstruction	1.5 / 0.75 mm
Transfer	Auto transfer of all data to PACS & to ANGIOVIS workstation