Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA •...
Transcript of Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA •...
![Page 1: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/1.jpg)
Outline: ContrastOutline: Contrast--enhanced enhanced MRAMRA
•• BackgroundBackground•• TechniqueTechnique•• Clinical IndicationsClinical Indications•• Future DirectionsFuture Directions
Disclosures:GE Health Care: Research supportConsultant: Bracco, Bayer
![Page 2: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/2.jpg)
The BasicsThe Basics•• During rapid IV infusion, Gadolinium During rapid IV infusion, Gadolinium
concentrated in arteries for 1 min.concentrated in arteries for 1 min.
•• Gadolinium is a potent T1 relaxation agent Gadolinium is a potent T1 relaxation agent in bloodin blood——T1T1bloodblood 1200 ms <100 ms 1200 ms <100 ms
•• Arterial MR signal enhancement is Arterial MR signal enhancement is proportional to T1 shorteningproportional to T1 shortening
OffOff--label use of Gadolinium Contrast Agentlabel use of Gadolinium Contrast Agent
![Page 3: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/3.jpg)
THE KEY TO MRTHE KEY TO MR--ANGIOANGIO
SI
TR (ms)
T1 = 10
T1 = 100 ms
T1 = 50 msT1-shortening
with
paramagnetic contrast
![Page 4: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/4.jpg)
Pre During Post
ContrastContrast--enhanced MRAenhanced MRA
![Page 5: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/5.jpg)
ContrastContrast--enhanced MRAenhanced MRA
During Post
![Page 6: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/6.jpg)
ContrastContrast--enhanced MRA enhanced MRA methodmethod
•• T1 weighted fast GRET1 weighted fast GRE•• 3D acquisition3D acquisition•• Tr < 5 msTr < 5 ms•• Te < 1 ms Te < 1 ms •• Flip = 30 degreesFlip = 30 degrees•• Gadolinium Dose: 20 cc at 2 cc/sGadolinium Dose: 20 cc at 2 cc/s
Common features of technique:Common features of technique:
Nikola TeslaNikola Tesla
![Page 7: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/7.jpg)
HOW MUCH CONTRAST?
Dose mmol/kg• Aorta 0.1 - 0.2 (20cc)• Renal arteries/SMA 0.1 - 0.2 (30cc)• Runoff 0.2 (40cc)
MRA is an off-label use of Gd
flow rate = 3 ml/sec for renals
![Page 8: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/8.jpg)
Pitfalls: TimingPitfalls: Timing
-5
0
5
10
15
20
0 20 40 60 80 100 120 140
Time (s)
ArterialArterial
VenousVenousTissueTissue
![Page 9: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/9.jpg)
Timing ArtifactsTiming Artifacts
![Page 10: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/10.jpg)
echo45°
Fourier
Transform
![Page 11: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/11.jpg)
kx
ky
k-Space Signal Image
DetailDetail
ContrastContrast
![Page 12: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/12.jpg)
A = 1% A = 99% A = 100%
+
+
=
=
![Page 13: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/13.jpg)
→ k-space sampling and image reconstruction strategies help to achieve high spatial resolution time-resolved MR angiograms.
Spatial Resolution
Temporal Resolution
SNR CNR
MRA Remains A Balancing Act MRA Remains A Balancing Act
![Page 14: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/14.jpg)
3D3D TTime ime RResolved esolved IImaging of maging of CContrast ontrast KKineticsinetics(TRICKS)(TRICKS)
aka: TREAT, DIRKSaka: TREAT, DIRKS
AD C CB B D ky
kz
Korosec et al.,Magn. Reson. Med. 1996
ky
kz
![Page 15: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/15.jpg)
3D TRICKS: Technique3D TRICKS: Technique
C(I)D(I)
B(I)A
... ...D A C A B A D A C A B A D10 11 12 13 14 15 16 17 18 19 20 21 22Time frame
FFTImage attime frame 15
Contrast curve ArteryVein
![Page 16: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/16.jpg)
3D TRICKs Acquisition3D TRICKs Acquisition
kx
ky
kz
k-space
Scan Time = TR × (PE × Slice) × Ave
image-space3D FFT⇒A
CB
Korosec, et al., MRM 36:345-51;1996
Time-Resolved Imaging of Contrast Kinetics
![Page 17: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/17.jpg)
3D TRICKs Acquisition3D TRICKs Acquisition
ΔT = TR × (PE × Slice)/3ΔT = 5 ms × (128 × 32)/3 = 6.8 sec
A A AB C
A B A C A B A C A B
![Page 18: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/18.jpg)
Frame Time 5.6 s
TR = 10.8 (1996)
3D TRICKS
512 x 128 x16
construction time 1996: 6 hours, one graduate stude
![Page 19: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/19.jpg)
Outline: TimeOutline: Time--resolved MRAresolved MRA
•• BackgroundBackground•• TechniqueTechnique•• Clinical IndicationsClinical Indications•• Future DirectionsFuture Directions
![Page 20: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/20.jpg)
Clinical IndicationsClinical Indications
•• Lower extremity runoff evaluationLower extremity runoff evaluation•• Asymmetric flow statesAsymmetric flow states•• Upper extremity MRAUpper extremity MRA•• Mass evaluation and characterizationMass evaluation and characterization•• Congenital heart diseaseCongenital heart disease•• Venous diseaseVenous disease•• Aortic diseaseAortic disease
![Page 21: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/21.jpg)
R BACKGROUND TISSUE SUPPRESSION
Benefits of 3D CE MRA with subtractionBenefits of 3D CE MRA with subtraction2D TOF 3D CEMRA
![Page 22: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/22.jpg)
1. Distal StationTime-resolved MRA10 cc Gd at 1 cc/sec
20 cc Gd Single Phase3. Pelvis: Centric
1
3
22. Thighs: TRICKS 10 cc at 1 cc/sec
![Page 23: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/23.jpg)
Improved Peripheral MRAImproved Peripheral MRA
•• Significantly more arteries Significantly more arteries diagnostic withdiagnostic with TRICKS TRICKS
•• Significantly more venous Significantly more venous contamination with moving contamination with moving SmartStepSmartStep in lower stationin lower station
••n=20, p < 0.05n=20, p < 0.05
Smartstep TRICKS
Hany TF, et al Radiology 2001;221:266-272.
![Page 24: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/24.jpg)
Benefits of timeBenefits of time--resolved imaging resolved imaging protocolprotocol
Left Popliteal Occlusion
![Page 25: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/25.jpg)
Benefits of timeBenefits of time--resolved imagingresolved imaging
![Page 26: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/26.jpg)
Thromboangitis ObliteransThromboangitis Obliterans
![Page 27: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/27.jpg)
13 y/o with Tetrology of Fallot post13 y/o with Tetrology of Fallot post--repairrepair
![Page 28: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/28.jpg)
Right PA enlargement causes SVC Right PA enlargement causes SVC obstructionobstruction
Sagittal reformatSagittal reformat
![Page 29: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/29.jpg)
Vascular Access EvaluationVascular Access Evaluation
Rotate MIPCollapsed Time Frames
![Page 30: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/30.jpg)
Secondary PAH due to chronic thromboembolic diseaseSecondary PAH due to chronic thromboembolic disease
Courtesy of Stephan Schoenberg et al
![Page 31: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/31.jpg)
Outline: TimeOutline: Time--resolved MRAresolved MRA
•• BackgroundBackground•• TechniqueTechnique•• Clinical IndicationsClinical Indications•• Future DirectionsFuture Directions
Spatial Resolution
Temporal Resolution
SNR CNR
![Page 32: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/32.jpg)
Traditional Traditional ““CartesianCartesian”” sampling of ksampling of k--spacespace
2D-FFT
![Page 33: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/33.jpg)
Alternate Trajectories: Radial Alternate Trajectories: Radial SamplingSampling•• Sampling along radial spokes (2DSampling along radial spokes (2D--PR)PR)
2D-FFT
![Page 34: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/34.jpg)
Characteristics of Radial SamplingCharacteristics of Radial Sampling
kx
ky
![Page 35: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/35.jpg)
HYPR HYPR –– Radial Acquisition Radial Acquisition –– FootFootFOV = 300 mm
512 x 512 x 26 (ZIP 52)
Voxel size0.59 x 0.59 x 3.0 (-1.5) mm
Frame Time = 2.0 Sec
16 proj/frame
Speedup(Cartesian) = 32512 PE/16 proj
Speedup(radial) = 50804 proj/16 proj3D HYPR
![Page 36: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/36.jpg)
3D TOF CE MRA DSA
Pitfalls: ResolutionPitfalls: Resolution
![Page 37: Outline: Contrast-enhanced MRA - Advanced Body Imaging...Outline: Contrast-enhanced MRA • Background • Technique • Clinical Indications • Future Directions Disclosures: GE](https://reader036.fdocuments.net/reader036/viewer/2022071420/61190a520b33836671782b41/html5/thumbnails/37.jpg)
Summary: TimeSummary: Time--resolved MRA resolved MRA
•• Eliminates need for accurate timing of contrast Eliminates need for accurate timing of contrast injection injection –– less need for radiologist supervisionless need for radiologist supervision
•• Allows high temporal and spatial resolution Allows high temporal and spatial resolution simultaneouslysimultaneously
•• Allows detection of nonAllows detection of non--uniform or asymmetric flowuniform or asymmetric flow
•• Automated process with essentially no postAutomated process with essentially no post--processing processing
•• Clinical indications expanding beyond arterial Clinical indications expanding beyond arterial disease onlydisease only
•• Need for visualization with 4D processing to take full Need for visualization with 4D processing to take full f fd t f ll th i f ti