helga castagnoli | Università degli Studi di Firenze (University of Florence) (original) (raw)

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Papers by helga castagnoli

European Journal of Nuclear Medicine and Molecular Imaging, Aug 16, 2016

Aims Myocardial blood flow <1.1 mL/min/g following dipyridamole (Dip-MBF) assessed by positron em... more Aims Myocardial blood flow <1.1 mL/min/g following dipyridamole (Dip-MBF) assessed by positron emission tomography (PET) was identified in 2003 as an important outcome predictor in hypertrophic cardiomyopathy (HCM), based on scans performed in the 90s. However, such extreme Dip-MBF impairment is rarely observed in contemporary cohorts. We, therefore, reassessed the Dip-MBF threshold defining high-risk HCM patients. Methods Dip-MBF was measured using 13 N-ammonia in 100 HCM consecutive patients, prospectively enrolled and followed for 4.0 ± 2.2 years. Outcome was assessed based on tertiles of Dip-MBF. The study end-point was a combination of cardiovascular death, progression to severe functional limitation, cardioembolic stroke, life-threatening ventricular arrhythmias. Results Global Dip-MBF was 1.95 ± 0.85, ranging from 0.7 to 5.9 mL/min/g. Dip-MBF tertile cutoff values were: 0.73 to 1.53 mL/min/g (lowest), 1.54 to 2.13 mL/min/g (middle), and 2.14 to 5.89 mL/min/g (highest). During follow-up, lowest tertile Dip-MBF was associated with sevenfold independent risk of unfavorable outcome compared to the other two tertiles. Dip-MBF 1.35 mL/min/g was identified as the best threshold for outcome prediction. Regional perfusion analysis showed that all cardiac deaths (n = 4) occurred in patients in the lowest tertile of lateral wall Dip-MBF (≤1.72 mL/min/g); septal Dip-MBF was not predictive. Conclusions Dip-MBF confirms its role as potent predictor of outcome in HCM. However, the threshold for prediction in a contemporary cohort is higher than that reported in earlier studies. Dip-MBF impairment in the lateral wall, possibly reflecting diffuse disease extending to non-hypertrophic regions, is a sensitive predictor of mortality in HCM.

European Journal of Nuclear Medicine and Molecular Imaging, Jun 27, 2015

Purpose Transmural abnormalities in myocardial blood flow (MBF) are important causes of ischaemia... more Purpose Transmural abnormalities in myocardial blood flow (MBF) are important causes of ischaemia in patients with left ventricular (LV) hypertrophy. The study aimed to test whether pixel-wise parametric mapping of 13 NH 3 MBF can reveal transmural abnormalities in patients with hypertrophic cardiomyopathy (HCM). Methods We submitted 11 HCM patients and 9 age-matched controls with physiological LV hypertrophy to rest and stress (dipyridamole) 13 NH 3 PET. We measured MBF using a compartmental model, and obtained rest and stress parametric maps. Pixel MBF values were reorganized to obtain subendocardial and subepicardial MBF of LV segments. Results MBF at rest was higher in the subendocardial than in the subepicardial layer: 0.78±0.19 vs. 0.60±0.18 mL/min/g in HCM patients; 0.92±0.24 vs. 0.75±0.24 mL/min/g in controls (both p < 0.0001). Transmural perfusion gradient (TPG=subendocardial MBF/subepicardial MBF) at rest was similar: 1.35±0.31 in HCM patients; 1.28±0.27 in controls (NS). During stress, controls maintained higher subendocardial MBF: 2.44 ± 0.54 vs. 1.96 ± 0.67 mL/min/g tissue (p < 0.0001), with a TPG of 1.33± 0.35 (NS vs. rest). In HCM patients, the difference between subendocardial and subepicardial MBF was reduced (1.46 ± 0.48 vs. 1.36 ± 0.48 mL/min/g tissue, p<0.01) and TPG decreased to 1.11± 0.34 (p<0.0001 vs. rest and vs. controls). In HCM patients 8 of 176 segments had subendocardial MBF less than −2 × SD of the mean, versus none of 144 segments in controls (p<0.01). Conclusion Pixel-wise parametric mapping of 13 NH 3 MBF enables the identification of transmural abnormalities in patients with HCM.

European Journal of Nuclear Medicine and Molecular Imaging, 2016

European Journal of Nuclear Medicine and Molecular Imaging, 2015

European Journal of Nuclear Medicine and Molecular Imaging, 2015

European Journal of Nuclear Medicine and Molecular Imaging, Aug 16, 2016

Aims Myocardial blood flow <1.1 mL/min/g following dipyridamole (Dip-MBF) assessed by positron em... more Aims Myocardial blood flow <1.1 mL/min/g following dipyridamole (Dip-MBF) assessed by positron emission tomography (PET) was identified in 2003 as an important outcome predictor in hypertrophic cardiomyopathy (HCM), based on scans performed in the 90s. However, such extreme Dip-MBF impairment is rarely observed in contemporary cohorts. We, therefore, reassessed the Dip-MBF threshold defining high-risk HCM patients. Methods Dip-MBF was measured using 13 N-ammonia in 100 HCM consecutive patients, prospectively enrolled and followed for 4.0 ± 2.2 years. Outcome was assessed based on tertiles of Dip-MBF. The study end-point was a combination of cardiovascular death, progression to severe functional limitation, cardioembolic stroke, life-threatening ventricular arrhythmias. Results Global Dip-MBF was 1.95 ± 0.85, ranging from 0.7 to 5.9 mL/min/g. Dip-MBF tertile cutoff values were: 0.73 to 1.53 mL/min/g (lowest), 1.54 to 2.13 mL/min/g (middle), and 2.14 to 5.89 mL/min/g (highest). During follow-up, lowest tertile Dip-MBF was associated with sevenfold independent risk of unfavorable outcome compared to the other two tertiles. Dip-MBF 1.35 mL/min/g was identified as the best threshold for outcome prediction. Regional perfusion analysis showed that all cardiac deaths (n = 4) occurred in patients in the lowest tertile of lateral wall Dip-MBF (≤1.72 mL/min/g); septal Dip-MBF was not predictive. Conclusions Dip-MBF confirms its role as potent predictor of outcome in HCM. However, the threshold for prediction in a contemporary cohort is higher than that reported in earlier studies. Dip-MBF impairment in the lateral wall, possibly reflecting diffuse disease extending to non-hypertrophic regions, is a sensitive predictor of mortality in HCM.

European Journal of Nuclear Medicine and Molecular Imaging, Jun 27, 2015

Purpose Transmural abnormalities in myocardial blood flow (MBF) are important causes of ischaemia... more Purpose Transmural abnormalities in myocardial blood flow (MBF) are important causes of ischaemia in patients with left ventricular (LV) hypertrophy. The study aimed to test whether pixel-wise parametric mapping of 13 NH 3 MBF can reveal transmural abnormalities in patients with hypertrophic cardiomyopathy (HCM). Methods We submitted 11 HCM patients and 9 age-matched controls with physiological LV hypertrophy to rest and stress (dipyridamole) 13 NH 3 PET. We measured MBF using a compartmental model, and obtained rest and stress parametric maps. Pixel MBF values were reorganized to obtain subendocardial and subepicardial MBF of LV segments. Results MBF at rest was higher in the subendocardial than in the subepicardial layer: 0.78±0.19 vs. 0.60±0.18 mL/min/g in HCM patients; 0.92±0.24 vs. 0.75±0.24 mL/min/g in controls (both p < 0.0001). Transmural perfusion gradient (TPG=subendocardial MBF/subepicardial MBF) at rest was similar: 1.35±0.31 in HCM patients; 1.28±0.27 in controls (NS). During stress, controls maintained higher subendocardial MBF: 2.44 ± 0.54 vs. 1.96 ± 0.67 mL/min/g tissue (p < 0.0001), with a TPG of 1.33± 0.35 (NS vs. rest). In HCM patients, the difference between subendocardial and subepicardial MBF was reduced (1.46 ± 0.48 vs. 1.36 ± 0.48 mL/min/g tissue, p<0.01) and TPG decreased to 1.11± 0.34 (p<0.0001 vs. rest and vs. controls). In HCM patients 8 of 176 segments had subendocardial MBF less than −2 × SD of the mean, versus none of 144 segments in controls (p<0.01). Conclusion Pixel-wise parametric mapping of 13 NH 3 MBF enables the identification of transmural abnormalities in patients with HCM.

European Journal of Nuclear Medicine and Molecular Imaging, 2016

European Journal of Nuclear Medicine and Molecular Imaging, 2015

European Journal of Nuclear Medicine and Molecular Imaging, 2015