Differential diagnosis of cardiac masses using T1 and T2 mapping

Background: Cardiac/pericardial masses represent a heterogeneous group of lesions, including benign and malignant neoplasms, as well as pseudo-tumoral entities, such as thrombi or inflammatory formations. These findings are mostly detected occasionally by echocardiography but, despite the wide availability, it often lacks the capability to differentiate among various types of masses. In this context, cardiovascular magnetic resonance (CMR) is the non-invasive imaging modality of choice for further evaluation, offering qualitative and quantitative multiparametric tissue characterization techniques. Particularly, native T1 and T2 mapping techniques, providing tissue relaxation time assessment, offer a significative contribute to the diagnostic work-up, potentially opening new clinical decision-making scenarios in patients with suspected cardiac masses.

Methods: Thirteen patients consecutively referred to our center to perform CMR for cardiac masses from February 2022 to July 2025 were included. CMR protocol for masses characterization included cineSSFP sequences, T1 Black-blood, TIRM T2, MOLLI and T2p-SSFP sequences for T1 and T2 mapping respectively, Fast GRE T1 sequences for perfusion, PSIR T1 sequences for early and late gadolinium enhancement detection. We excluded four patients with no further clinical correlation or histological definition.

Results: Nine patients (5 males, mean age 55.6 ± 12.8 years) were included. Masses were located in the right (n=2) and left atrium (n=2), right (n=1) and left ventricle (n=2), and within the pericardium (n=2). [Table 1] Two masses were thrombi that resolved with anticoagulant therapy. The distinction between the recent and the chronic thrombus was based on T1 relaxation times, reflecting early fibrin content with hemosiderin deposition versus fibrotic remodeling. [Figure 1] In the case of pericardial cysts, T1 mapping values differed depending on their content. A left atrial myxoma was characterized by high T1 and T2 values, consistent with myxoid and vascular stroma, while a lithomyxoma exhibited lower T1 values and heterogeneously elevated T2 values. A rhabdomyoma located in the left ventricular wall demonstrated mapping values consistent with intracellular glycogen accumulation. [Figure 2] A pleomorphic sarcoma in the left atrium showed markedly elevated native T1 and T2 values, suggestive of high cellularity, necrosis, and edema. Lastly, a suspected heteroplastic lesion in the right ventricular wall revealed mapping values compatible with normal myocardial tissue, allowing the exclusion of a malignant lesion.

Conclusion: CMR offers a comprehensive multiparametric approach for the evaluation of cardiac and pericardial masses, allowing for non-invasive differentiation between benign, malignant, and pseudo-tumoral lesions. T1 and T2 mapping techniques provide additional quantitative insight into tissue composition, improving diagnostic accuracy and potentially guiding clinical management and therapeutic strategies.

Table 1. Collected masses

Diagnosis	Location	T1 mapping (ms)	T2 mapping (ms)
Old thrombus	Right atrium	1300	59
Recent thrombus	Left Ventricle	800	90
Hemorrhagic Cyst	Pericardium	1480	443
Proteinaceous Cyst	Pericardium	3082	408
Lithomyxoma	Right atrium	1350	60
Myxoma	Left atrium	1864	97
Malignant Pleomorphic Sarcoma	Left atrium	1204	59
Rhabdomyoma	Left Ventricle	1187 (core 700)	39 (core 55)
Suspected eteroplasia	Right Ventricle	1080	56

Figure 1. Recent (A) vs old thrombus (B)
Figure 2. A, myxoma. B, lithomyxoma. C, rhabdomyoma.