4D Flow MRI for Diagnosing an Unroofed Coronary Sinus in a 61-Year-Old Male

Presenting Author(s)

• 

  Masaki Kodaira, MD, PhD

  Associate Professor
  Keio University
  Shinjuku, Tokyo, Japan

Primary Author(s)

• 

  Masaki Kodaira, MD, PhD

  Associate Professor
  Keio University
  Shinjuku, Tokyo, Japan

Co-Author(s)

• RT

  Ryo Tsukada

  Deputy Chief
  Keio University Hospital, Japan
• TO

  Takayuki Oyanagi, MD

  Associate Professor
  Keio University Hospital
  Shinjuku, Tokyo, Japan
• SM

  Shigeki Miura, RT

  Technologist
  Keio University Hospital
  Shinjuku, Tokyo, Japan
• NS

  Naofumi Suumitomo, MD, PhD

  Associate Professor
  Keio University Hospital
  Shinjuku, Tokyo, Japan
• SM

  Sari Motomatsu

  Chief
  Keio University Hospital, Japan
• HM

  Hirozumi Mori, MD

  Instructor
  Keio University School of Medicine, Tokyo, Japan
• TN

  Takehiro Nakahara, MD, PhD

  Associate Professor
  Keio University School of Medicine, Tokyo, Japan
• NK

  Naritaka Kimura, MD, PhD

  Assistant Professor
  Keio University School of Medicine, Tokyo, Japan
• YY

  Yoshitake Yamada, MD, PhD

  Keio University School of Medicine, Japan
• MJ

  Masahiro Jinzaki, MD

  Professor
  Keio University School of Medicine, Japan
• MI

  Masaki Ieda, MD, PhD

  Professor
  Keio University Hospital
  Shinjuku, Tokyo, Japan

Description of Clinical Presentation: A 61-year-old man presented with exertional dyspnea and was referred to our center after a transthoracic echocardiography revealed right ventricular dilatation and an enlarged coronary sinus. Despite these findings, no intracardiac shunt was identified on echocardiography, raising concern about an underlying congenital anomaly that may not be readily detectable by standard imaging.

Diagnostic Techniques and Their Most Important Findings: Cardiac magnetic resonance (CMR) was performed using a 1.5T GE Artist scanner, with post-processing conducted on cvi42 (version 6.2.2; Circle Cardiovascular Imaging). Steady-state free precession (SSFP) cine imaging demonstrated right ventricular dilatation. Two-dimensional phase-contrast (2D PC) analysis revealed a Qp/Qs ratio of 2.1:1.0. Three-dimensional (3D) whole-heart imaging identified a partial absence of the coronary sinus (CS) roof (Figure 1). Four-dimensional (4D) flow MRI clearly delineated left-to-right shunting (19.75ml) across this defect (Figure 2).

Learning Points from this Case: CMR with 4D flow MRI provides comprehensive diagnostic information, allowing clear visualization of coronary sinus unroofing as well as the resultant left-to-right shunting.

Figure 1. 3D whole heart imaging showing unroofing of the coronary sinus.
Figure 2. 4D flow MRI fused with cine imaging demonstrates shunting via the unroofed coronary sinus.