Giant Coronary Artery Pseudoaneurysm: a Rare Cause of "Cardiac Mass"

Presenting Author(s)

• GR

  Giuseppe Rovere, MD

  Medical Doctor, Diagnostic Radiologist
  Fondazione Policlinico Universitario "A.Gemelli" - IRCCS, Rome (Italy)
  Rome, Lazio, Italy

Primary Author(s)

• GR

  Giuseppe Rovere, MD

  Medical Doctor, Diagnostic Radiologist
  Fondazione Policlinico Universitario "A.Gemelli" - IRCCS, Rome (Italy)
  Rome, Lazio, Italy

Co-Author(s)

• AM

  Alessandro Marchetti, MD

  Medical Doctor, Radiology Resident
  Catholic University of Rome “Agostino Gemelli" University Polyclinic Foundation IRCCS
  Roma, Lazio, Italy
• PS

  Pietro Sciaccotta

  Medical Doctor, Radiology resident
  Catholic University of Rome “Agostino Gemelli" University Polyclinic Foundation IRCCS, Italy
• MS

  Martina Schiavo

  Medical Doctor, resident radiologist
  Catholic University of Rome “Agostino Gemelli" University Polyclinic Foundation IRCCS, Italy
• 

  Francesco Lauriero, MD

  Medical Doctor, Diagnostic Radiologist
  Fondazione Policlinico Universitario "A. Gemelli" - IRCCS, Rome (Italy)
  Rome, Lazio, Italy
• AM

  Agostino Meduri, MD

  Assistant Professor
  Catholic University of Rome, "Agostino Gemelli" University Polyclinic Foundation IRCCS- Rome (Italy), Italy
• 

  Luigi Natale, MD

  Medical Doctor, Associate Professor of Radiology
  Catholic University - Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome (Italy)
  Rome, Lazio, Italy
• RM

  Riccardo Marano, MD

  Medical Doctor, Associate Professor of Radiology
  Università Cattolica - Fondazione Policlinico Universitario "Agostino Gemelli" - IRCCS, Rome (Italy)
  Rome, Lazio, Italy

Description of Clinical Presentation: A 31-year-old woman presented to the emergency department due to recurrent episodes of chest pain with dyspnea, palpitations, and dizziness for 3 weeks. Physical examination, blood tests and ECG were normal. Transthoracic echocardiography revealed a large intrapericardial mass compressing the right cardiac chambers, with moderate pericardial effusion; systolic global and regional function of both ventricles was preserved. Chest CT confirmed the presence of a round lesion within the right atrioventricular groove with mean density of 61 HU and no significant contrast-enhancement. Patient underwent explorative sternotomy but enucleation was not feasible and cytology was inconclusive.

Diagnostic Techniques and Their Most Important Findings: For further characterization, cardiac-MRI (CMR) was performed at 1.5 T (Philips Ingenia), using the standard protocol for cardiac masses in our institution (table 1), demonstrating a 6.9×7.6×8.8 cm mass in the right atrioventricular groove, compressing the right atrium, the right ventricular inflow tract and the superior vena cava, with heterogeneously hyperintense signal in BB-T1W and T2W-STIR sequences. Perfusion imaging showed a focal peripheric area of early enhancement along the posterior wall of the lesion, just after the LV cavity phase, persisting into the myocardial phase. There was a subendocardial infarct in the LV basal lateral wall (segment 4 and 5) extending into the medium infero-lateral wall (segment 11) of LCX territory. Coronary CT-angiography (CTA) and invasive coronary angiography showed direct communication of the enhancing portion of the lesion with the right coronary artery, trough a slender acute marginal/atrial branch; these findings were consistent with a giant pseudoaneurysm of the right coronary artery. Reduced opacification of an obtuse marginal branch of LCX, of the right postero-lateral branch and distal portion of posteriore descending artery were also observed, with multiple stenosis and ectasia of intervening tracts. Following multidisciplinary discussion, the patient underwent PCI with covered stent; follow-up CTA showed complete exclusion of the pseudoaneurysm.

Learning Points from this Case: Giant coronary artery pseudoaneurysms are an extremely rare cause of cardiac mass, as only a few cases have been described in literature. Given the young age of our patient, no established cardiovascular risk factors and history of trauma, and involvement of LCX/right postero-lateral branch, we suspect the pseudoaneurysm to be vasculitic in origin. In this context, CMR is essential to differentiate from other types of cardiac masses, as it allows not only detailed assessment of lesion morphology and location, but also non-invasive tissue characterization and impact on cardiac function.

Standard CMR protocol for cardiac masses in our institution. b-SSFP: balanced steady-state free precession. FS: fat-saturated. STIR: short-tau inversion recovery. MOLLI: modified look-locker inversion recovery. mGRASE: multi-echo gradient spin-echo. EGE: early gadolinium-enhancement. FSPGR: fast-spoiled gradient echo. LGE: late gadolinium enhancement.

Sequence	Plane / Coverage	Slice Thickness
b-SSFP cine	2-chamber, 4-chamber and short-axis views	8 mm
Axial T1W-BB	Transaxial, whole thorax	5 mm
Axial T1W-BB FS	Transaxial, whole thorax	5 mm
T2W-STIR	Best plane for mass study (usually short-axis view)	5 mm
Native T1 Mapping (MOLLI)	Short-axis view	10mm (1-2 slices including the mass)
T2 Mapping (mGraSE)	Short-axis view	10mm (1-2 slices including the mass)
First-pass perfusion (rest)	3 short-axis slices + 1 2-chamber and 4 chamber slice	10 mm
EGE	Best plane for mass study (TI 500-550 ms; 2 min after contrast injection)	5 mm
FSPGR-3D T1W post-contrast	Whole heart	2 mm
LGE	2-chamber, 4-chamber and short-axis views	8 mm
T1 Mapping enhanced (MOLLI)	Short-axis view	10mm (1-2 slices including the mass)

TTE 4-chambers view (a) and CMR cine-BTFE 4-chambers (b) and short-axis (c) views show a large rounded lesion within the right atrioventriculare groove, compressing the right atrium, inflow tract of the RV and superior vena cava. The lesion shows heterogeneously hyperintense signal in T2W-STIR (d) and BB-T1W images (e-f), with and without fat saturation.
(a) to (d) first pass rest perfusion images show no enhancement of the lesion in the RV (a) and LV (b) cavity phases. Just after the LV phase (c) a focal area of enhancement can be seen along the posterior wall, persisting into the myocardial phase (d); the same area can be seen in FSPGR T1W post-contrast (e) and delayed enhancement (f) images. Ischemic LGE along the basal lateral wall of the left ventricle, extending into the medium infero-lateral wall is also observed.
Axial (a) and coronal (b) MIP reformat images from CCT show a focal area of enhancement within the peripheric portion of the lesion, communicating with the right coronary artery trough a slender acute marginal branch/atrial branch; the same finding is confirmed by invasive coronary angiography (c-d) which also shows multiple stenosis with ectasia of intervening tracts of the right postero-lateral branch, the distal portion of posterior descending artery, and an obtuse marginal branch of LCX. Follow-up CTA after PCI shows patency of the overlapping stents in the proximal tract of RCA, with complete exclusion of the pseudoaneurysm.