Aurélie Bourdon

Comparative values of gated blood-pool SPECT and CMR for ejection fraction and volume estimation.

ObjectiveGated blood-pool single-photon emission computed tomography (GBPS) was compared with cardiac magnetic resonance (CMR) for the measurement of left ventricular (LV) and right ventricular (RV) ejection fractions (EF) and volumes [end-diastolic volume (EDV) or end-systolic volume (ESV)] in a mixed population. MethodsThirty patients (70% men; mean age: 61±14 years) referred for various symptoms or heart diseases, predominantly ischemic, were included. GBPS data were analyzed using segmentation software described earlier based on the watershed algorithm. CMR images were acquired for both ventricles at the same time using a steady-state-free precession sequence and short-axis views. No compensation for papillary muscles was used. LVEF and RVEF and volumes were assessed with GBPS and CMR and were compared. ResultsLVEF and volumes were correlated (P<0.001). The difference in LVEF between GBPS and CMR was not significant (P=0.063). The limits of agreement were close for LVEF (−11 to 15%) and wider for LV volumes (−82 to 11 ml for EDV and −52 to 15 ml for ESV), with higher volume values obtained with CMR (mean differences of 36±24 ml for EDV and 19±17 ml for ESV). The RVEF and volumes assessed by GBPS and CMR were correlated (P<0.001). The difference in RVESV between GBPS or CMR was not significant (P=0.136). The limits of agreement were relatively close for all RV parameters (−15 to 8% for EF; −44 to 22 ml for EDV, and −25 to 21 ml for ESV). In 24 patients without valvulopathy or shunt, the difference between LV stroke volume and RV stroke volume was lower with GBPS than with CMR (9±14 ml and 18±13 ml, respectively, with P=0.027). ConclusionGBPS is a simple and widely available technique that can assess both LVEF and RVEF, and volumes with slight differences compared with CMR.

Optimization of a simultaneous dual-isotope 201 Tl/ 123 I-MIBG myocardial SPECT imaging protocol with a CZT camera for trigger zone assessment after myocardial infarction for routine clinical settings: Are delayed acquisition and scatter correction necessary?

BackgroundDual-isotope 201Tl/123I-MIBG SPECT can assess trigger zones (dysfunctions in the autonomic nervous system located in areas of viable myocardium) that are substrate for ventricular arrhythmias after STEMI. This study evaluated the necessity of delayed acquisition and scatter correction for dual-isotope 201Tl/123I-MIBG SPECT studies with a CZT camera to identify trigger zones after revascularization in patients with STEMI in routine clinical settings.MethodsSixty-nine patients were prospectively enrolled after revascularization to undergo 201Tl/123I-MIBG SPECT using a CZT camera (Discovery NM 530c, GE). The first acquisition was a single thallium study (before MIBG administration); the second and the third were early and late dual-isotope studies. We compared the scatter-uncorrected and scatter-corrected (TEW method) thallium studies with the results of magnetic resonance imaging or transthoracic echography (reference standard) to diagnose myocardial necrosis.ResultsSummed rest scores (SRS) were significantly higher in the delayed MIBG studies than the early MIBG studies. SRS and necrosis surface were significantly higher in the delayed thallium studies with scatter correction than without scatter correction, leading to less trigger zone diagnosis for the scatter-corrected studies. Compared with the scatter-uncorrected studies, the late thallium scatter-corrected studies provided the best diagnostic values for myocardial necrosis assessment.ConclusionsDelayed acquisitions and scatter-corrected dual-isotope 201Tl/123I-MIBG SPECT acquisitions provide an improved evaluation of trigger zones in routine clinical settings after revascularization for STEMI.

Is computed tomography attenuation correction more efficient than gated single photon emission computed tomography analysis in improving the diagnostic performance of myocardial perfusion imaging in patients with low prevalence of ischemic heart disease

ObjectiveThe purpose of this study was to compare computed tomography (CT)-based attenuation correction (AC) using a hybrid single photon emission computed tomography (SPECT)-CT system and quantitative analysis of wall thickening using gated SPECT with regard to the diagnostic accuracy of myocardial perfusion imaging. Materials and methodsWe prospectively included 70 patients with low prevalence of acute coronary artery disease who underwent a myocardial stress–rest SPECT study. Interpretation was based on supine nongated SPECT data with (AC) or without (NC) CT-based attenuation correction, and on gated SPECT data without attenuation correction (GNC). The scintigraphic diagnosis was obtained using standard automated quantitative analysis software and compared with a 23±14 months’ clinical follow-up for 57 patients or with the results of a coronary angiography for 13 patients. ResultsThe sensitivity, specificity, and overall accuracy were, respectively, 77, 60, and 63% for NC SPECT, 67, 81, and 79% for AC SPECT, and 69, 98, and 93% for GNC SPECT. The initial diagnosis was modified in about one-third of the cases for both AC and GNC, this rate being independent of any clinical parameter (including BMI) except sex (two to four times more artifact correction in men). ConclusionIts widespread availability, cost effectiveness, safety in terms of radiation exposure, and ability to significantly improve myocardial perfusion imaging specificity and accuracy make gated SPECT a self-sufficient modality for coronary artery disease screening and follow-up, whereas CT-AC should be discussed on a case-by-case basis.

Diagnosis of silent myocardial ischemia during the staging of HIV-associated lymphoma with FDG PET/CT.

Fasting 18F fluoro-deoxy-glucose positron emission tomography examinations are routinely performed for the staging of HIV-associated lymphomas. In addition to possible comorbidity factors, the chronic inflammation that occurs in HIV-infected patients together with the metabolic side effects of antiretroviral therapy increases the risk for coronary artery disease. Moreover, HIV-infected patients are likely to develop polyneuropathies due to the viral infection or to the side effects of long-term protease or nucleoside reverse transcription inhibitor treatments.We report a case that illustrates the need to suspect the diagnosis of silent myocardial ischemia among HIV-positive patients with myocardial F-18 fluoro-deoxy-glucose uptake involving a coronary artery territory.

RV function improvement following nitric oxide inhalation demonstrated by gated blood pool SPECT in a patient with primary pulmonary hypertension

A 30-year-old woman with a history of dyspnoea and recurrent syncope was diagnosed with primary pulmonary hypertension (PPH). Right cardiac catheterization demonstrated pre-capillary PH with elevated mean pulmonary arterial pressure at 52 mmHg, low occlusive pulmonary arterial pressure at 5 mmHg, and elevated pulmonary vascular resistance at 638 d.s.cm. Pulmonary arterial pressure and resistance were normalized after nitric oxide (NO) inhalation. Calcium blocker medication (nifedipine 150 mg day) was initiated. The patient was explored using gated blood pool SPECT at baseline and after NO inhalation (10 ppm). SPECT data were post-processed using in-house dedicated software (TomPool). Figure 1 shows left (LV, in red) and right ventricle (RV, in blue) time-volume curves fitted using a deformable reference curve model. Figure 2 displays bi-ventricular 3D surface rendering and polar plots of local ejection fraction (EF). Baseline acquisition showed normal LV function. Global RV EF was measured at 59%, within the normal range (56% ± 8%). There was an RV annular peri-apical area of moderate hypokinesia. After NO inhalation, LV function was globally stable, whereas global RV EF increased to 69%. Segmental contractility maps showed a clear improvement in the RV free wall contractility

Area at risk can be assessed by iodine-123-meta-iodobenzylguanidine single-photon emission computed tomography after myocardial infarction: a prospective study

Background Myocardial salvage is an important surrogate endpoint to estimate the impact of treatments in patients with ST-segment elevation myocardial infarction (STEMI). Aim The aim of this study was to evaluate the correlation between cardiac sympathetic denervation area assessed by single-photon emission computed tomography (SPECT) using iodine-123-meta-iodobenzylguanidine (123I-MIBG) and myocardial area at risk (AAR) assessed by cardiac magnetic resonance (CMR) (gold standard). Patients and methods A total of 35 postprimary reperfusion STEMI patients were enrolled prospectively to undergo SPECT using 123I-MIBG (evaluates cardiac sympathetic denervation) and thallium-201 (evaluates myocardial necrosis), and to undergo CMR imaging using T2-weighted spin-echo turbo inversion recovery for AAR and postgadolinium T1-weighted phase sensitive inversion recovery for scar assessment. Results 123I-MIBG imaging showed a wider denervated area (51.1±16.0% of left ventricular area) in comparison with the necrosis area on thallium-201 imaging (16.1±14.4% of left ventricular area, P<0.0001). CMR and SPECT provided similar evaluation of the transmural necrosis (P=0.10) with a good correlation (R=0.86, P<0.0001). AAR on CMR was not different compared with the denervated area (P=0.23) and was adequately correlated (R=0.56, P=0.0002). Myocardial salvage evaluated by SPECT imaging (mismatch denervated but viable myocardium) was significantly higher than by CMR (P=0.02). Conclusion In patients with STEMI, 123I-MIBG SPECT, assessing cardiac sympathetic denervation may precisely evaluate the AAR, providing an alternative to CMR for AAR assessment.