CAD: New Methods
Thu-Thao Le, PhD, FSCMR
Junior Principal Investigator
National Heart Centre Singapore, Singapore
Thu-Thao Le, PhD, FSCMR
Junior Principal Investigator
National Heart Centre Singapore, Singapore
Jen Bryant, MSc, Phd, FSCMR
Senior Principal Radiographer / Manager
National Heart Centre Singapore
Yiu-Cho Chung, PhD
Senior Scientist
Siemens Healthcare Pte Ltd Singapore, Singapore
Daniel Stäb, PhD
Senior Scientist
Siemens Healthcare Pty Ltd, Melbourne, Australia
Melbourne, Victoria, Australia
Peter Speier, PhD
Principal Key Expert
Magnetic Resonance, Siemens Healthcare GmbH, Erlangen, Germany
Erlangen, Bayern, Germany
Sakinah Hanafi, BSc
Senior Radiographer
National Heart Centre Singapore
Singapore, Singapore
Alicia Er Ting, BSc
Senior Radiographer
National Heart Centre Singapore, Singapore
Yiying Han, BSc
Senior Radiographer
National Heart Centre Singapore, Singapore
Chee Yang Chin, MD
Senior Consultant
National Heart Centre Singapore, Singapore
Jonathan Yap, MD
Consultant
National Heart Centre Singapore, Singapore
Khung Keong Yeo, MD
Senior Consultant
National Heart Centre Singapore, Singapore
Kay Woon Ho, MD
Senior Consultant
National Heart Centre Singapore, Singapore
Jack Tan, MD
Senior Consultant
National Heart Centre Singapore, Singapore
Exercise stress using in-scanner supine cycling ergometer to assess regional wall motion abnormalities (RWMA), perfusion defects, viability and exercise capacity in a single examination has been shown to accurately diagnose patients with suspected coronary artery disease (CAD), validated by invasive fractional flow reserve (FFR)1. While perfusion assessment might be more sensitive than RWMA, which is a later stage of the ischemic cascade, its sensitivity in exercise stress may be affected by compromised temporal and spatial resolutions when imaging at high heart rate. We hypothesize that simultaneous multi-slice (SMS), which increases myocardial coverage without sacrificing spatial resolution, would improve the sensitivity of exercise first-pass perfusion.
Methods:
40 patients with suspected CAD (recruited to EMPIRE Trial – NCT03217227) underwent exercise CMR imaging (1.5T Aera, Siemens) and FFR procedure for validation of CAD. Perfusion images were acquired using a SMS bSSFP prototype sequence with rf phase cycling based CAIPIRINHA encoding and GC-LOLA2, where 4 slices were covered per heartbeat. Test sensitivity was compared to data previously acquired in another 60 EMPIRE patients using a single slice bSSFP perfusion sequence where 4 slices were covered in 2 heartbeats.
Results:
At median peak exercise heart rate of 121 [IQR 106 – 131] bpm, SMS offers better spatial resolution and 2 times higher temporal resolution compared to non-SMS acquisition (Table). SMS increases sensitivity of exercise-induced first-pass perfusion for diagnosing significant CAD (84.0% [95%CI 63.9 - 95.5]), compared to single slice acquisition in 2 heartbeats (66.7% [95%CI 47.2 – 82.7]).
Conclusion:
Despite high heart rate and breathing motion at peak exercise, perfusion imaging with SMS bSSFP which allows coverage of 4 slices in a single heartbeat provides good sensitivity for diagnosing CAD, referenced to gold standard invasive FFR.