Pulmonary MR Angiography
Sagittal Oblique Coronal MIP
Martin R. Prince
with slides borrowed from
Tom Grist, MDJorg Debatin, MDJim Meaney, MDPiotr Wielopolski, PhDQian Dong, MDRuth Carlos, MDDavid Stafford-Johnson, MDStefan Schoenberg, MDGus Bis, MDVic Ferarri, MDStefan Reuhm, MD
Pulmonary Embolism• > 600,000 per year
• 30% mortality
• Difficult to diagnosis• V/Q - 64% indeterminate
• Angio is expensive + risks
• CTA safer but nephrotoxicity
• Anticoagulation: 7% risk of
major complication
MR Angiography Protocol• Coronal 3D Volume
• image both lungs simutaneously• large dose of Gd
(<180 lb 2 bottles, 42ml)(>180 lb 3 bottles, 63ml)
• one injection
• Sagittal 3D Volumes• small FOV, no wrap• two separate injections • main PA excluded
Coronal 3D Gd:MRA
Pulmonary MRA Technique
• Sagittal Locator 1 min
• Coronal 3D Volume x 3 1.5 min
Total imaging time <3 min
Prescribing Coronal 3D Volume• Posterior to spinal cord
• Anterior to the ascending aorta
• Large FOV to prevent wrap
• No spoiling
• Fast scan for breath holding• Thick slices: 3-5 mm• Zero interpolation (ZIP x 2)• Gradient upgrade for short TR• Partial Fourier Imaging
• Multiphase
Injecting the Gadolinium• 2 ml/sec (as fast as you can)• 6-10 second scan delay for arterial phase• equilibrium phase• rest to catch breath • equilibrium phase again • ventilated patient: suspend in max inspiration
Arterial Phase Equilibrium Phase
Acute Pulmonary Embolism
Chronic Pulmonary Embolism
Pulmonary Embolism:Diagnosis with MRA
Author Year # of pt Techniques Sensitivity Specificity
Grist 1993 20 TOF 92% 63%
Isoda 1995 18 3D Gd 80% 95%
Laissy 1995 28 TOF + Gd 87% 95%
Wolff 1996 34 2D Gd 72% 94%
Meaney 1997 30 3D Gd 87% 97%
Gupta 1999 36 3D Gd 85% 96%
Diagnosis of Pulmonary Embolism* with MRA (n=30)
1 2 3
Sensitivity 100% 87% 75%
Specificity 95% 100% 95%
*Meaney et al. NEJM 366:1422-7, 1997.
Diagnosis of Pulmonary Embolism* with MRA (n=36)
Reviewer 1 2
Sensitivity 92% 77% Specificity 83% 91%PPV 75% 83%NPV 95% 88%*Gupta et al Radiology 1999; 210:353-359
Shortness of Breath with cough in a 51-year-old female
Coronal MIP
Magnification
Reformation
Partial anomlous pulmonary venous return from the right upper lobe
Coronal MIP
Magnification
Reformation
46-year-old female with machinery murmur
Axial T1
Patent Ductus Arteriosus
Axial T1
Pulmonic stenosis
Blood pool agent MRA
Summary• 3D Gd:MRA useful
• Safeno nephrotoxicityno ionizing radiationno arterial catheterization
• Fast (30 second breath hold)
• Accurate
• Better with blood pool?