Late Enhancement of a Left Ventricular Cardiac Fibroma Assessed With Gadolinium-Enhanced Cardiovascular Magnetic Resonance
A 4-year-old patient was referred to our department and underwent gadolinium-enhanced cardiovascular MR (CMR) because of a suspected left ventricular mass. The infant was referred for an ECG before dental surgery; ECG revealed negative T waves in leads D1, AVL, V4, V5, and V6. Echocardiography showed a heterogeneous mass of the left ventricular lateral wall inside the pericardial space, 4.0×2.0 cm in size, with reduced lateral wall motion. The global left ventricular function was normal.
CMR was performed under sedation with a 1.5-T magnet (Gyroscan Intera Master, Philips Medical System) with a cardiac phased-array multicoil. First, “black-blood” multiplanar morphological (Figure 1A) without and with fat suppression and cine “bright blood” balanced fast field-echo images were obtained (Figure 1B). These images revealed a hypointense mass arising within the left ventricular free wall, suggestive of cardiac fibroma. Dynamic contrast-enhanced CMR perfusion images were acquired during gadolinium-DTPA (0.1 mmol/kg) injection; after 10 minutes, 3D segmented IR-GRE technique to evaluate the delayed enhancement phase (DECMR) adjusting inversion time (230 ms) to null normal myocardium was performed. In early perfusion phase, the tumor demonstrated no contrast enhancement (Figure 2), but in the delayed phase, the tumor showed intense enhancement with central hypointensity compared with normal myocardium (Figure 3A and 3B), suggesting the nature of fibroma. The explanation of this late hyperenhancement pattern on DECMR is that microscopically fibromas are a collection of fibroblasts interspersed among large amounts of collagen. It is known that gadolinium bound to DTPA diffuses into the interstitial space but not across cell membranes. In fibromas, there is a great extracellular space for gadolinium accumulation, and the distribution kinetics are slower than normal myocardium; these phenomena result in a delayed and persistently higher relative concentration of gadolinium with late enhancement.
With these CMR findings, the infant was diagnosed as having left ventricular fibroma, and he did not undergo endomyocardial biopsy and surgical excision because of the absence of symptoms and the high level of risk for the patient’s life. At a 6-month follow-up, no changes in clinical symptoms and ECG signs were found; moreover, at an echocardiography performed at the same time, no changes of the mass were shown, thus confirming the benign nature of the lesion.