Perforated Sinus of Valsalva Aneurysm with Combined Obstructive and Shunting Physiology: Anatomical and Functional Assessment by cineMR and 4D Flow MRI

Description of Clinical Presentation: A 43 years-old man with no relevant cardiac history presented with progressive dyspnea. Transthoracic echocardiography suggested pulmonary hypertension and raised the suspicion of a left-to-right shunt, initially interpreted as a membranous ventricular septal defect. To further investigate, pulmonary/cardiac CT angiography was performed, that excluded both ventricular septal defects and pulmonary embolism, but demonstrated markedly delayed contrast progression. CT revealed also an uncommon condition: a right sinus of Valsalva aneurysm protruding into the right ventricular outflow tract (RVOT), associated with secondary right ventricular dilation and hypertrophy, and giant dilatation of the pulmonary trunk without wall abnormalities.

Diagnostic Techniques and Their Most Important Findings: While CT provided a useful anatomical overview, it was insufficient to fully delineate the complex relationship between the aneurysm, the RVOT, and the pulmonary trunk. CMR combined anatomical definition and functional assessment. CineMR images revealed biventricular dilation, RV free wall hypertrophy and accelerated RVOT flow. CMR also demonstrated that the aneurysm was complicated by perforation, producing an aortic-to-RV shunt (Qp/Qs: 1.5). This was most evident during diastole, accentuated by the cyclic modification of pressure gradient. Advanced flow imaging played a decisive role: 2D and 4D flow CMR revealed abnormal hemodynamics in the pulmonary trunk, with large vortices persisting into late systole causing the giant aneurysmal dilatation. The integration of multiparametric CMR thus provided a comprehensive understanding of the pathophysiology, which could not be achieved with CT alone. Imaging findings were further corroborated intraoperatively and on postoperative follow-up CMR, which documented restoration of normal anatomy and reverse remodeling of the right ventricle.

Learning Points from this Case:

• 
  Sinus of Valsalva aneurysm may rarely present with both RVOT obstruction and intracardiac shunting, mimicking congenital septal defects.
  
  


• 
  Cardiac CT offers initial anatomical overview but may be insufficient for complete characterization.
  
  


• 
  CMR is essential for integrating anatomical and functional information, with 4D flow providing unique insights for understanding complex flow disturbances and pressure-volume interactions.
  
  


• 
  The multimodal integration of anatomical and functional imaging was fundamental for surgical planning and for documenting postoperative recovery.
  
  

Cardiac CT demonstrating a right sinus of Valsalva aneurysm (white arrowheads) protruding into the RVOT. Due to the low attenuation difference between the right heart cavity and the aortic lumen, the thin aneurysmal borders and the presence of a shunt cannot be clearly delineated.
Cine-MR images showing a round defect in the wall of the right sinus of Valsalva aneurysm (arrow), associated with biventricular dilatation and right ventricular wall hypertrophy. MR angiography demonstrates a large aneurysm of the pulmonary trunk.
2D phase-contrast images (left) demonstrate RVOT flow acceleration, while 4D flow images (middle and right) reveal a large vortex (*) in the pulmonary trunk persisting into diastole, together with an aortic-to-RV shunt (arrow).