DISCLOSURE OBJECTIVES PULMONARY VEIN STENOSIS DIAGNOSTIC TOOLS. Echo with Doppler Catheterization with angiography CT angiography MRI

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1 1 2 ND INTERNATIONAL CONFERENCE: NEONATAL AND CHILDHOOD PULMONARY VASCULAR DISEASE, MARCH 13-14, 2009, SAN FRANCISCO, USA PATHOPHYSIOLOGY OF PULMONARY VEIN FLOW: IMAGING NORMAL AND ABNORMAL PULMONARY VEIN FLOW AND THE DIAGNOSIS OF CONGENITAL PULMONARY VEIN STENOSIS Shi-Joon Yoo, MD University of Toronto Canada DISCLOSURE No disclosures OBJECTIVES To describe normal PV flow Anatomy Velocities Volumes Patterns To discuss flow changes in stenotic PV At upstream from the stenosis At downstream from the stenosis At pulmonary arteries of the affected and unaffected lungs Recruitment of systemic-pulmonary arterial collaterals PULMONARY VEIN STENOSIS DIAGNOSTIC TOOLS Echo with Doppler Catheterization with angiography CT angiography MRI

2 2 Why MRI? Why MRI? Non-invasive Complete anatomy of pulmonary circulation Blood flow changes in obstructed and unobstructed pulmonary veins and supplying pulmonary arteries Ventricular function

3 3 MRA-ECHO CORRELATION n = 28 patients (2 weeks -15yrs, 2-66 kg) 43% Confirmed echo diagnosis 29% Confirmed uncertain findings 29% Provided a new diagnosis Valsangiacomo et al. Pediatr Radiol 2003;33:92-98 PHASE-CONTRAST VELOCITY MAPPING Static spin V 0 Moving spin V 1 Moving spin V 2

4 4 Imaging plane Positive Gradient B0 Imaging plane Positive Gradient After t Static spin V 0 Static spin V 0 Moving spin V 1 Moving spin V 1 Moving spin V 2 Moving spin V 2 Imaging plane Positive Gradient Negative Gradient After t Imaging plane Positive Gradient Negative Gradient Static spin V 0 Static spin V 0 Moving spin V 1 Moving spin V 2 Moving spin V 1 Moving spin V 2 Φ 1 Φ 2 Φ Velocity

5 5 INTERNAL VALIDATION PHASE-CONTRAST MR ADVANTAGES svc AsAo DsAo 1. Data from whole cross-sectional area 2. No influence of air, bones and scars 3. Unlimited choice of imaging plane 4. Reference data from other vessels 5. Easy internal validation of data Q AsAo Q SVC + Q DsAo PHASE-CONTRAST MR DISADVANTAGES NORMAL PULMONARY VENOUS FLOW 1. Low temporal resolution (>15 msec) 2. Hard to apply for vessels < 3 mm 3. Pacemaker, metallic implants, etc.

6 6 Smiseth, et al. JACC 1999;34: Push Pull Modified with permissions Backward push Ventricular Atrial Ventricular Atrial Early systolic (es) LA relaxation Early systolic (es) Late systolic (ls) RV contraction LV contraction LA relaxation LA capacity

7 7 Ventricular Atrial Ventricular Atrial Early systolic (es) LA relaxation Early systolic (es) LA relaxation Late systolic (ls) RV contraction LV contraction LA capacity Late systolic (ls) RV contraction LV contraction LA capacity Early diastolic (d) LV relaxation LV stiffness Early diastolic (d) LV relaxation LV stiffness Atrial reversal (a) LV stiffness LA contraction Unobstructed PV after PV surgery PV FLOW PATTERN IS INFLUENCED BY: Early systolic (es) Late systolic (ls) Early diastolic (d) Ventricular RV contraction LV contraction LV relaxation LV stiffness Atrial LA relaxation LA capacity Atrial reversal (a) LV stiffness LA contraction Heart rate Age Respiration LA pressure

8 8 PULMONARY VENOUS FLOW DURING EARLY NEONATAL LIFE QUANTIFICATION OF PULMONARY VENOUS FLOW Agata et al. J Br Heart J 1994;71: Quantification of pulmonary blood flow when pulmonary artery cannot be imaged. Quantification of systemic-pulmonary collateral arterial flow. PA FLOW VOLUME _ PV FLOW VOLUME NORMAL PULMONARY VENOUS FLOW VOLUMES (n=12) Blood Flow (L/min/m 2 ) Mean SD Qpa Qpv Qrpa Qrpv Qlpa Qlpv Goo et al. J Magn Reson Imaging 2009;29:

9 9 NORMAL PULMONARY VENOUS FLOW VOLUMES (n=12) Paired t- Test Correlation P value Coefficient P value Qrpa vs. Qrpv Qlpa vs. Qlpv Qpa vs. Qpv Goo et al. J Magn Reson Imaging 2009;29: Case. Ebstein s malformation with huge cardiomegaly PULMONARY VEIN STENOSIS Congenital Acquired as a de novo lesion Acquired complicating PV surgery

10 10 Case. 16M Boy with Hemoptysis Born at 26w of gestation Had bronchopulmonary dysplasia 26 patients in 10 years ( ) Prematurity in 16 (61%) (odds ratio, 10.2) Bronchopulmonary dysplasia in 11 (42%) Genetic syndromes in 8 (30%) Trisomy 21 in 5 Cath in 8 (31%): 3/8 for elevated RVP at echo Cardiac defects in 23 (88%) PDA (12), ASD (10), VSD (8), AVSD (4) Surgical interventions before diagnosis of PV stenosis Wiebe et al. Pediatric Radiology 2003;33:

11 11 PULMONARY VEIN STENOSIS MRI ASSESSMENT 88% 12% Right pulmonary artery Left pulmonary artery Contrast-enhanced angiography Phase-contrast velocity mapping Ascending aorta Descending aorta at diaphragm MPA, RPA, LPA Individual pulmonary veins Ventricular function study a b a a - Downstream b b - Upstream

12 12 PHASE-CONTRAST EVALUATION OF PULMONARY VEINS (n=14) Flow pattern in upstream from obstruction is as informative as that in downstream and easy to obtain. Flow pattern in upstream from obstruction is characterized by diminished velocity and loss of biphasic pattern. Flow pattern in obstructed veins vary according to the redistribution of pulmonary arterial blood flow as well as the severity of obstruction. Valsangiacomo et al. Pediatr Radiol 2003;33: PULMONARY ARTERIAL FLOW IN PULMONARY VENOUS OBSTRUCTION (n=12) PV obstruction causes abnormal PA flow with abnormal blood flow distribution. Significant unilateral stenosis is associated with diminished systolic forward flow and diastolic reversal in ipsilateral PA, and diastolic forward flow in contralateral PA. Flow information from PA branches within the lungs would be important. Roman et al. Pediatric Radiology 2005;35:

13 13 RLPV RUPV RLPV Case. 9-month old male with repeated respiratory difficulties RUPV RLPA RUPAs

14 14 BEFORE SURGERY Cole s procedure at 10 month Increased work with breathing and O 2 requirement at 6 months after surgery Bronchiolitis or re-stenosis? AFTER SURGERY R/L = 73/27 R/L = 99/1

15 15 Case. 5-year old female with right atrial isomerism, TAPVC, unbalnaced AVSD, DORV, PS S/P TAPVC repair and bilateral BCPC 1 ST MR 2 ND MR 3 RD MR Age (month) RPA (l/min/m 2 ) RPV (l/min/m 2 ) LPA (l/min/m 2 ) LPV (l/min/m 2 ) Grosse-Wortmann et al. Cardiol Young 2008;18:240 1 ST MR 2 ND MR 3 RD MR Age (month) RPA (l/min/m 2 ) RPV (l/min/m 2 ) C R = RPA-RPV LPA (l/min/m 2 ) LPV (l/min/m 2 ) C L = LPA-LPV ST MR 2 ND MR 3 RD MR Age (month) RPA (l/min/m 2 ) RPV (l/min/m 2 ) C R = RPA-RPV LPA (l/min/m 2 ) LPV (l/min/m 2 ) C L = LPA-LPV Qp/Qs

16 16 1 ST MR 2 ND MR 3 RD MR Age (month) RPA (l/min/m 2 ) RPV (l/min/m 2 ) C R = RPA-RPV LPA (l/min/m 2 ) LPV (l/min/m 2 ) C L = LPA-LPV Qp/Qs EDV (ml/m 2 ) na SUMMARY Normal pulmonary venous flow consists of early systolic, late systolic and diastolic forward flow peaks and late diastolic downward peak. Pulmonary vein stenosis causes loss of normal phasic changes in flow pattern with decelerated flow in upstream and accelerated flow in downstream. SUMMARY Pulmonary vein stenosis causes redistribution of pulmonary arterial flow. The pulmonary arterial flow to the affected side is characterized by reduced forward flow in systole and reversed flow in diastole. Pulmonary venous obstruction can be associated with development of systemic arterial collaterals to the affected lung region. SUMMARY MRI IS A VERY USEFUL AND POWERFUL IMAGING TOOL IN THE EVALUATION OF PULMONARY VENOUS ABNORMALITIES.

17 17 THANK YOU! Special Thanks to: Emanuela Valsangiacomo, MD Christian Kellenberger, MD Kevin Roman, MD Fahad AlHabshan, MD Ai-Min Sun, MD Abdulmajeed Al-Otay, MD Hyun-Woo Goo, MD Lars Grosse-Wortmann, MD Christopher Macgowan, PhD