Cardio-pulmonary involvement in pulmonary arterial hypertension: A perfusion and innervation scintigraphic evaluation.

BACKGROUND: Pulmonary arterial hypertension (PAH) is characterized by the right ventricle (RV) remodeling and pulmonary endothelial dysfunction. We studied cardiac perfusion and innervation in PAH with a cadmium-zinc-telluride (CZT) scanner and lung uptake impairment of 123I-metaiodobenzylguanidine (123I-MIBG). METHODS: In 13 patients with newly diagnosed PAH and 11 dilated cardiomyopathies (DCM, for comparative purposes), we assessed early and delayed 123I-MIBG uptake ratios of lung-to-mediastinum (L/M) and heart-to-mediastinum (H/M) on anterior planar images. A quantitative myocardial innervation with 123I-MIBG and perfusion with 99mTc-tetrofosmin using CZT-SPECT was performed. All patients underwent right heart catheterization. RESULTS: Early and delayed L/M ratios in PAH were lower than DCM (1.47 ± 0.14 vs 1.98 ± 0.11 and 1.40 ± 0.13 vs 1.83 ± 0.09; P < .001), while early and delayed H/M were impaired but not different (1.73 ± 0.20 vs 1.65 ± 0.18 and 1.73 ± 0.27 vs 1.58 ± 0.19). RV perfusion and early innervation were significantly higher in PAH compared to DCM (68.4 ± 13.4 vs 28.6 ± 4.1 and 58.8 ± 9.3 vs 27 ± 2.2; P < .001); delayed RV innervation was not evaluable. RV/LV perfusion and innervation ratios were significantly related (R = 0.74; P < .0001) and had a significant correlation with clinical, hemodynamic, and morpho-functional parameters, including L/M ratios. CONCLUSION: Cardio-pulmonary scintigraphy through a perfusion and innervation study is feasible and may identify pulmonary vascular and RV remodeling, as in PAH.

Changes in left ventricle myocardial volume during stress test using cadmium-zinc-telluride cardiac imaging: Implications in coronary artery disease.

BACKGROUND: Cadmium-zinc-telluride (CZT) SPECT allows the estimation of left ventricle myocardial volume (LVMV). We tested the clinical relevance of rest-stress LVMV changes (Δ LVMV) in detecting coronary artery disease (CAD, coronary stenosis > 70%), using CZT-SPECT. METHODS: We prospectively enrolled 512 consecutive patients with known or suspected CAD (mean age: 70.3 ± 9.2 years, 72% male) for stress-rest myocardial perfusion imaging (MPI, single-day stress-rest protocol). We quantified summed stress scores (SSS), summed rest scores, and summed difference scores, together with LVMV and ejection fraction (EF) after stress and at rest. All patients underwent coronary angiography within 30 days. RESULTS: Two hundred seventy-two patients had CAD at coronary angiography. ΔLVMV ≤ 5 mL, corresponding to 6% of change from rest LVMV, was the best predictor of CAD (AUC = 0.831, 79% sensitivity, 82% specificity), irrespective of the stress protocol (dipyridamole or exercise stress) and independently of MPI-SSS, LV EF, and clinical history (P = 0.004). Integrated discrimination improvement (IDI) and net reclassification improvement (NRI) were significant for the addition of ΔLVMV ≤ 5 mL (IDI = 6.1%, P < 0.0001; NRI = 29.7%, P = 0.02) to MPI-SSS, whereas the other parameters were not. CONCLUSIONS: The evaluation of ΔLVMV using CZT-SPECT can improve the diagnostic accuracy in predicting the presence of CAD when added to conventional MPI.

Head-to-head comparison of a CZT-based all-purpose SPECT camera and a dedicated CZT cardiac device for myocardial perfusion and functional analysis.

PURPOSE: To compare the outputs of a novel all-purpose SPECT camera equipped with CZT detectors (Discovery NM/CT 670) with the state-of-the-art represented by a dedicated CZT (Alcyone, Discovery 530c) cardiac camera in patients submitted to myocardial perfusion imaging (MPI). METHODS: We included 19 patients that underwent sequential low-dose 99mTc-tetrofosmin (148-185 MBq during stress and 296-370 MBq at rest) MPI with Alcyone and Discovery 670 cameras. Quantitative (% tracer's uptake) and semi-quantitative analyses of perfusion data were performed for each scan. Moreover, major left ventricular (LV) functional and structural parameters were derived from each camera and compared. RESULTS: The two cameras showed excellent correlation for segmental myocardial % uptake at stress (R = 0.90; P < 0.001) and at rest (R = 0.88; P < 0.001) with narrow Bland-Altman limits of agreement. The level of diagnostic agreement of Discovery 670 and Alcyone cameras regarding perfusion analysis was excellent (Cohen's κ 0.85). Similarly, the two cameras showed excellent correlation in the evaluation of LV ejection fraction (R = 0.95), peak filling rate (R = 0.97), and mass (R = 0.98). CONCLUSIONS: Our preliminary results suggest that MPI with an all-purpose Discovery 670 CZT-SPECT camera is feasible, comparing well with the current state-of-the-art technology.