The Role of FDG-PET in Patients with Epilepsy Related to Periventricular Nodular Heterotopias: Diagnostic Features and Long-Term Outcome.

BACKGROUND AND PURPOSE: Periventricular nodular heterotopias (PNHs) are frequently associated with drug-resistant epilepsy (DRE). Although magnetic resonance imaging (MRI) can define the morphological features of PNHs, still there is a need to assess their metabolic activity in order to provide useful information on epileptogenicity and long-term outcome. To that end, we investigated the ability of 18 F-FDG PET to identify seizure onset zone in order to assess the metabolic activity of the ectopic neurons and to provide prognostic information on the postsurgical outcome. METHODS: Sixteen patients (6 men and 10 women; ranging between 24 and 53 years of age) with PNHs-related DRE were evaluated. All patients underwent clinical evaluation, Stereo-electroencephalogram (SEEG), brain MRI, and 18 F-FDG brain PET/CT. PET images were superimposed on the patient-specific 3-dimensional-brain MRI. The metabolic activity of each nodule and of their cortex was visually and semiquantitatively assessed. The outcome after intervention was assessed in all patients using Engel classification. RESULTS: Thirty-one heterotopic sites were identified. Twenty-one of 23 nodules with detectable electric activity on SEEG were identified by PET (91.3%), while 5 of 8 of nodules without electric activity showed no metabolism on PET (62.5%). Overall, the concordance between SEEG and FDG-PET was 26/31 (83.9%). Furthermore, cortical metabolic alterations were depicted, correlating with epileptogenic areas. A favorable postsurgical outcome was reported in 13 patients (81.3%). The presence of a hypometabolic nodule significantly correlated with a worse outcome after surgical therapy (P = .036). CONCLUSIONS: In PNHs-related epilepsy, FDG-PET more accurately identifies epileptogenic foci, which aids surgical planning and in postoperative seizure control.

Predictive and prognostic value of left ventricular mechanical dyssynchrony assessed by myocardial perfusion single photon emission computed tomography in asymptomatic patients under hemodialysis.

BACKGROUND: Patients under hemodialysis (HD) have an increased risk of major adverse cardiac events (MACEs). In these patients, myocardial perfusion scintigraphy (MPS) provides useful prognostic information. Left ventricular mechanical dyssynchrony (LVD) has been proven to predict all-cause death in patients under HD. It remains unclear, whether the same prognostic value pertains also to the prediction of MACEs. PATIENTS AND METHODS: Ninety patients under HD (duration range: 2-216 months) with neither history nor symptoms of coronary artery disease at the time of MPS were retrospectively evaluated. All underwent clinical evaluation and MPS with dipyridamole stress test. MPS was reprocessed to derive left ventricular ejection fraction (EF), perfusion scores [summed stress score (SSS) and summed difference score (SDS)] and LVD (phase histogram bandwidth and phase SD).ResultsMACEs were reported in 10 (11.1%) patients as assessed at more than 2 years of follow-up (median 29 months). At univariate analysis, a correlation was demonstrated between MACEs and LVD (P<0.001), BMI (P=0.04), ECG changes during stress (P=0.03), dyspnea (P=0.02), SSS (P=0.04) and SDS (P=0.02). At stepwise multivariate analysis, only LVD (P<0.001), SSS (P=0.01) and SDS (P=0.001) were independent predictors of MACEs. No thresholds of SSS or SDS showed predictive value (P=0.79 for SSS ≥4, P=0.10 for SSS >8 and P=0.66 for SDS ≥2). At survival analysis, patients with LVD had a significantly shorter MACE-free survival (P<0.001). This predictive value held true even in patients with an unremarkable pattern of perfusion. CONCLUSION: In asymptomatic patients without known coronary artery disease under HD, LVD is highly predictive of the onset of MACEs at more than 2 years of follow-up and provides incremental value over perfusion scores alone. A phase analysis on gated MPS should be routinely performed in these patients to yield useful prognostic information.

Usefulness of chronotropic incompetence to dipyridamole in predicting myocardial perfusion defects in heart transplant recipients.

The aim of this report was to assess the relation between heart rate response to dipyridamole infusion and perfusion defects at quantitative sestamibi single-photon emission computed tomographic imaging. We demonstrated in 166 heart transplant recipients that chronotropic incompetence to dipyridamole is the only significant and independent predictor of perfusion defects.

Functional derangement and cardiac innervation in the apical ballooning syndrome: a 123I-meta-iodobenzylguanidine scintigraphic and dobutamine stress echocardiographic study.

Several cases of transient left ventricular apical ballooning syndrome have already been described, but the pathophysiological mechanisms of this syndrome still remain unclear. We report the case of a patient evaluated in the acute phase of apical ballooning by coronary angiography and echocardiography who was submitted to I-meta-iodobenzylguanidine (MIBG) myocardial scintigraphy and dobutamine stress echocardiography one month after the discharge. MIBG scintigraphy demonstrated a decreased tracer uptake in the apical and periapical anterior regions, whilst myocardial perfusion at rest was normal. Dobutamine induced an increased left ventricular outflow tract gradient and hypokinesis in the apical and periapical segments, mimicking the findings that occurred in the acute phase, and in agreement with the location of MIBG abnormalities. After a two-month treatment with carvedilol, MIBG uptake increased in the apical and periapical anterior regions.

Early detection of cardiac dysfunction in thalassemic patients by radionuclide angiography and heart rate variability analysis.

BACKGROUND: Cardiac dysfunction remains the major cause of death in beta-thalassemia. Aim of this study was to assess early myocardial damage in thalassemic patients with no symptoms or echocardiographic evidence of dysfunction at routine monitoring. METHODS: Twenty patients (seven females; median 25 yr [first quartile 22,third quartile 28]) with beta-thalassemia underwent radionuclide angiography (RNA) at rest and during low-dose dobutamine infusion (5-10 gamma/kg/min). Right and left ventricular ejection fractions (EF) were determined by first-pass method and gated equilibrium acquisition, respectively. Twenty-four-hour Holter monitoring with time-domain heart rate variability (HRV) assessment and echocardiographic follow-up (21 months [5,27]) were performed. RESULTS: Eleven patients showed regional wall motion abnormalities at RNA; left ventricular EF, HR and diastolic measurements significantly increased after dobutamine infusion. Patients with abnormal RNA right ventricular EF (n = 8, <0.45) showed lower echocardiographic left ventricular EF at the enrollment (0.54 [0.50,0.61] vs. 0.62 [0.56,0.67], P = 0.02) than those with a normal right ventricular EF. Patients with reduced standard deviation of the averages of RR intervals in all 5-minute periods of entire recording (SDANN) (n = 6, <100 ms), a measure of HRV, had lower echocardiographic left ventricular EF (0.53 [0.49,0.62] vs. 0.62 [0.56,0.66], P = 0.03) and lower fractional shortening (0.28 [0.25,0.32] vs. 0.36 [0.30,0.39], P = 0.003) at the enrollment than those with normal SDANN. No significant association was found between RNA and HRV measurements and follow-up left ventricular function. CONCLUSIONS: Right ventricular dysfunction and abnormal HRV may represent the early features of cardiac disease in thalassemic patients with no evidence of ventricular dysfunction at routine evaluation.