PET/CMR: One More Step Toward Noninvasive Morphofunctional Diagnosis of Cardiac Malignancies

Emerging role of PET/MR in the diagnosis and characterization of cardiotoxicity?

In cardiotoxicity, PET/MR affords an accurate evaluation of cardiovascular morphology, function, and also multi-parametric tissue characterization. A composite of several cardiac imaging parameters provided by the PET/MR scanner is likely to outperform a single parameter or imaging modality in the assessment and prediction of the severity and progression of cardiotoxicity but needing clinical investigations. Of particular interest, a heterogeneity map of single PET and CMR parameters could be perfectly correlated with the PET/MR scanner likely emerging as a promising marker of cardiotoxicity to monitor treatment response. While such functional and structural multiparametric imaging approach with cardiac PET/MR in the assessment and characterization of cardiotoxicity holds much promise, its validity and value in cancer patients treated with chemotherapy and/or radiation still needs to be assessed. The multi-parametric imaging approach with PET/MR, however, is likely to set new standards to develop predictive constellations of parameters for the severity and potential progression of cardiotoxicity that should afford timely and individualized treatment intervention to ascertain myocardial recovery and improved clinical outcome in these high-risk patients.

Comparing the diagnostic accuracy of PET and CMR for the measurement of left ventricular volumes and ejection fraction: a system review and meta-analysis

BACKGROUND

Cardiac magnetic resonance (CMR) has been recognized as the gold standard for the evaluation of left ventricular (LV) function. Cardiac gated PET allows the simultaneous assessment of LV function with the evaluation of myocardial perfusion and metabolism. But the correlations between PET and CMR remain controversial.

METHODS

We conducted a systematic electronic search of PubMed, Embase and the Cochrane Library . Forest plot, spearman correlation analysis and Bland-Altman analysis were used to evaluate the correlations between PET and CMR.

RESULTS

Pooled analysis of 13 studies showed that PET underestimated left ventricular end-diastolic volumes (LVEDV) [mean difference (MD), -15.30; 95% confidence interval (CI), -23.10 to -7.50; P  < 0.001] and left ventricular end-systolic volumes (LVESV) (MD, -6.20; 95% CI, -12.58 to 0.17; P  = 0.06) but not left ventricular ejection fraction (LVEF) (MD, -0.35; 95% CI, -1.75 to 1.06; P  = 0.63). Overall, there were very good correlations between PET and CMR measurements for LVEDV ( r , 0.897), LVESV ( r , 0.924) and LVEF ( r , 0.898). Subgroup analysis indicated that LVEDV ≥180 ml and LVEF <40% reduced the accuracy of PET, especially the measurement of LVEF ( r , LVEDV ≥180 vs . r , LVEDV < 180 : 0.821 vs. 0.944; r , LVEF < 40% vs . r , LVEF ≥40% : 0.784 vs. 0.901).

CONCLUSIONS

Correlations between PET and CMR measurements of LVEDV, LVESV and LVEF were excellent, but these two methods could not be used interchangeably for accurate measurements of LV volume and LVEF in patients with significantly increased LV volume and decreased LVEF.

Cutting-Edge Imaging of Cardiac Metastases from Neuroendocrine Tumors: Lesson from a Case Series

With the increasing availability of high-performance medical imaging for the management of patients with neuroendocrine tumors (NETs), a progressive growth of asymptomatic and incidentally detected cardiac metastases (CMs) has been observed in the recent years. In clinical practice, CMs of NENs are often incidentally detected by whole-body 68Ga-labeled somatostatin analogs or 18F-fluorodihydroxyphenylalanine positron emission tomography/computed tomography, and afterwards accurately characterized by cardiac magnetic resonance (CMR) and/or gated cardiac computed tomography when CMR is contraindicated or not available. The interpreting physician should familiarize with the main imaging features of CM, a finding that may be encountered in NETs patients more than previously thought. Herein, we present a case series of four patients with CMs from small-intestine NETs highlighting strengths and weaknesses of a multimodality imaging approach in clinical practice.