Late Gadolinium Enhancement Cardiac Magnetic Resonance Tissue Characterization for Cancer-Associated Cardiac Masses: Metabolic and Prognostic Manifestations in Relation to Whole-Body Positron Emission Tomography.

Background Cardiac magnetic resonance ( CMR) differentiates neoplasm from thrombus via contrast enhancement; positron emission tomography ( PET) assesses metabolism. The relationship between CMR contrast enhancement and metabolism on PET is unknown. Methods and Results The population included 121 cancer patients undergoing CMR and 18F-fluorodeoxyglucose (18F- FDG) - PET , including 66 with cardiac masses and cancer-matched controls. Cardiac mass etiology (neoplasm, thrombus) on CMR was defined by late gadolinium enhancement; PET was read blinded to CMR for diagnostic performance, then colocalized to measure FDG avidity. Of CMR -evidenced thrombi (all nonenhancing), none were detected by PET . For neoplasm, PET yielded reasonable sensitivity (70-83%) and specificity (75-88%). Lesions undetected by PET were more likely to be highly mobile ( P=0.001) despite similar size ( P=0.33). Among nonmobile neoplasms, PET sensitivity varied in relation to extent of CMR -evidenced avascularity; detection of diffusely enhancing or mixed lesions was higher versus predominantly avascular neoplasms (87% versus 63%). Colocalized analyses demonstrated 2- to 4-fold higher FDG uptake in neoplasm versus thrombus ( P<0.001); FDG uptake decreased stepwise when neoplasms were partitioned based on extent of avascularity on late gadolinium enhancement CMR ( P≤0.001). Among patients with neoplasm, signal-to-noise ratio on late gadolinium enhancement CMR moderately correlated with standardized uptake values on PET ( r=0.42-0.49, P<0.05). Mortality was higher among patients with CMR -evidenced neoplasm versus controls (hazard ratio: 1.99 [95% CI, 1.1-3.6]; P=0.03) despite nonsignificant differences when partitioned via FDG avidity (hazard ratio: 1.56 [95% CI, 0.85-2.74]; P=0.16). Among FDG-positive neoplasms detected concordantly with CMR , mortality risk versus cancer-matched controls was equivalently increased (hazard ratio: 2.12 [95% CI, 1.01-4.44]; P=0.047). Conclusions CMR contrast enhancement provides a criterion for neoplasm that parallels FDG -evidenced metabolic activity and stratifies prognosis. Extent of tissue avascularity on late gadolinium enhancement CMR affects cardiac mass identification by FDG - PET .

Prognostic utility of differential tissue characterization of cardiac neoplasm and thrombus via late gadolinium enhancement cardiovascular magnetic resonance among patients with advanced systemic cancer.

BACKGROUND: Late gadolinium enhancement (LGE-) cardiovascular magnetic resonance (CMR) is well-validated for cardiac mass (CMASS) tissue characterization to differentiate neoplasm (CNEO) from thrombus (CTHR): Prognostic implications of CMASS subtypes among systemic cancer patients are unknown. METHODS: CMASS + patients and controls (CMASS -) matched for cancer diagnosis and stage underwent a standardized CMR protocol, including LGE-CMR (IR-GRE) for tissue characterization and balanced steady state free precession cine-CMR (SSFP) for cardiac structure/function. CMASS subtypes (CNEO, CTHR) were respectively defined by presence or absence of enhancement on LGE-CMR; lesions were quantified for tissue properties (contrast-to-noise ratio (CNR); signal-to-noise ratio (SNR) and size. Clinical follow-up was performed to evaluate prognosis in relation to CMASS etiology. RESULTS: The study population comprised 126 patients with systemic neoplasms referred for CMR, of whom 50% (n = 63) had CMASS + (CNEO = 32%, CTHR = 18%). Cancer etiology differed between CNEO (sarcoma = 20%, lung = 18%) and CTHR (lymphoma = 30%, GI = 26%); cardiac function (left ventricular ejection fraction: 63 ± 9 vs. 62 ± 10%; p = 0.51∣ right ventricular ejection fraction: 53 ± 9 vs. 54 ± 8%; p = 0.47) and geometric indices were similar (all p = NS). LGE-CMR tissue properties assessed by CNR (13.1 ± 13.0 vs. 1.6 ± 1.0; p < 0.001) and SNR (29.7 ± 20.4 vs. 15.0 ± 11.4, p = 0.003) were higher for CNEO, consistent with visually-assigned diagnostic categories. CTHR were more likely to localize to the right atrium (78% vs. 25%, p < 0.001); nearly all (17/18) were associated with central catheters. Lesion size (17.3 ± 23.8 vs. 2.0 ± 1.5 cm2; p < 0.001) was greater with CNEO vs. CTHR, as was systemic disease burden (cancer-involved organs: 3.6 ± 2.0 vs. 2.3 ± 2.1; p = 0.02). Mortality during a median follow-up of 2.5 years was markedly higher among patients with CNEO compared to those with CTHR (HR = 3.13 [CI 1.54-6.39], p = 0.002); prognosis was similar when patients were stratified by lesion size assessed via area (HR = 0.99 per cm2 [CI 0.98-1.01], p = 0.40) or maximal diameter (HR = 0.98 per cm [CI 0.91-1.06], p = 0.61). CTHR conferred similar mortality risk compared to cancer-matched controls without cardiac involvement (p = 0.64) whereas mortality associated with CNEO was slightly higher albeit non-significant (p = 0.12). CONCLUSIONS: Among a broad cancer cohort with cardiac masses, CNEO defined by LGE-CMR tissue characterization conferred markedly poorer prognosis than CTHR, whereas anatomic assessment via cine-CMR did not stratify mortality risk. Both CNEO and CTHR are associated with similar prognosis compared to CMASS - controls matched for cancer type and disease extent.