123I-MIBG imaging in heart failure: impact of comorbidities on cardiac sympathetic innervation

Figures

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  Fig. 1. Graphical representation of sympathetic innervation in heart failure. In failing heart, activation of the sympathetic nervous system leads to elevated levels of Nepi, due to increased release and reduced uptake. The result is a persistent activation and subsequent desensitization of β-ARs, which in the long term determines cardiac damage and HF progression. This is usually reflected as decreased cardiac 123I-MIBG uptake (reduced H/M ratio) on imaging. Comorbidities and conditions such as aging contribute to impair cardiac adrenergic innervation, with a negative impact on HF progression and outcome. β-ARs, β-adrenergic receptors; DOPA, dihydroxyphenylalanine; DA, dopamine; Nepi, norepinephrine

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  Fig. 2. a 123I-MIBG CZT images of a diabetic patient with HF (LVEF 37%). 123I-MIBG H/M ratios obtained from planar equivalent and tomographic images showing an extensive area of reduced innervation in the apex and inferior wall of the left ventricle with total defect score (TDS) of 35. b 123I-MIBG CZT images of a non-diabetic patient with HF (LVEF 42%). 123I-MIBG H/M ratios obtained from planar equivalent and tomographic images showing a mild reduction of innervation in the apex of the left ventricle with total defect score (TDS) of 3

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  Fig. 3. a 123I-MIBG CZT images of a patient with HF (LVEF 32%) with obesity. An extensive area of reduced innervation in the apex, antero-septal, and inferior wall of the left ventricle was visible (red arrows). b.123I-MIBG CZT images of a patient with HF (LVEF 35%) without obesity. A mild reduction of innervation in the infero-lateral wall of the left ventricle was visible (red arrows)

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  Fig. 4. 99mTc-sestamibi (A) and 123I-MIBG (B) CZT images of a patient with HF (LVEF 47%). An area of partially preserved perfusion in the 99mTc-sestamibi images (white arrows) but reduced innervation in the 123I-MIBG images (red arrows), in the apex and infero-lateral wall of the left ventricle (mismatched area 10%) was visible