Characterization of Atypical Pheochromocytomas with Correlative MRI and Planar/Hybrid Radionuclide Imaging: A Preliminary Study

Pheochromocytomas may show atypical imaging findings leading to diagnostic pitfalls. We correlated the results of magnetic resonance imaging (MRI) with those of radionuclide studies in patients with pheochromocytomas. T2-weighted (-w), T1-w chemical-shift and T1-w dynamic contrast enhanced (DCE) MRI sequences were evaluated to assess tumor structure. 131Iodine metaiodobenzylguanidine (MIBG) scintigraphy, 18fluoro (F) deoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) or FDG PET/MRI were evaluated for direct comparison. Of a total of 80 adrenal lesions in 73 patients, 20 in 18 patients were pheochromocytomas. More than half (55%) of the pheochromocytomas (n = 11) had the typical increased signal intensity on T2-w and T1-w DCE, while the remaining (n = 9) lesions showed atypical findings; of these nine latter atypical lesions, seven (35%) were cystic (two totally, three predominantly and two partially) and two (10%) were hemorrhagic on MRI. In these atypical lesions, MIBG scintigraphy (n = 5), FDG PET/CT (n = 6) or FDG PET/MRI (n = 2) showed inhomogeneous tracer uptake in the residual viable tissue providing tumor characterization; however, one predominantly cystic pheochromocytoma showed false negative MIBG scan. Our preliminary results show that cystic degeneration may be frequent in pheochromocytoma being so marked that only a thin rim of viable cells may residue to disclose the true nature of the tumor. MRI findings together with those of correlative planar/hybrid radionuclide images are helpful to characterize these atypical pheochromocytomas. In particular, tumor accumulation of MIBG and/or FDG is able to classify these lesions as not simple cysts; in detail, the presence of partial MIBG uptake allows the diagnosis of pheochromocytomas, while the presence of partial FDG uptake generically reflects the presence of viable solid tissue of such cystic tumors.

Prognostic value of myocardial MIBG scintigraphy in acute ischemic stroke

Funding Acknowledgements Type of funding sources: None. Background Autonomic dysfunction is a common complication of acute ischemic stroke and has been associated with poor functional outcome and increased mortality. We investigated the potential relation between the myocardial washout rate (WOR) of 123I-meta-iodobenzylguanidine (123I-mIBG), as a measure of cardiac sympathetic activity, and functional outcome in acute ischemic stroke. Methods 38 patients with ischemic stroke (11 females, 72 years old [61-81)), underwent myocardial 123I-mIBG scintigraphy within the first week after stroke onset. Early (10 minutes post-injection (pi)) and late (4 hours pi) planar scans of the thoracic region were made. Regions of interest (ROI) were drawn over the mediastinum and the heart, and heart-to-mediastinum ratio (HMR) was calculated. Myocardial WOR was calculated as follows: (ROI heart early – ROI heart late)/ (ROI heart early) x 100%. Counts were corrected for background and counts in ROI heart late were corrected for decay. Patients were divided in 2 groups: those with a good functional outcome, defined as modified Rankin Scale (mRS) ≤ 2 at 3 months after stroke (i.e., patient is functionally independent), and those with a poor functional outcome, defined as a mRS > 2. Results Median WOR was 27,4 % (IQR 10,4-43,6). In univariate analysis, poor functional outcome after stroke was associated with age, stroke severity on admission (measured by the National Institutes of Health Stroke Scale (NIHSS)), beta-blocker use before and during hospitalization, WOR and late HMR. In subsequent multivariate analysis WOR (OR 1.087; 95% CI 1.003-1.177, p = 0.042) was an independent predictor of poor stroke outcome even after adjustment for age and NIHSS. Conclusions In patients with acute ischemic stroke, myocardial washout of 123I-mIBG predicts stroke outcome, even after adjustment for age and stroke severity on admission.

Value of cardiac 123I-mIBG scintigraphy in prognosis of catheter ablation outcome in patients with atrial fibrillation

Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Russian Science Foundation Background. Previous studies show inconsistent results on the role of innervation imaging (with 123I-mIBG) in predicting late atrial fibrillation (AF) recurrence after catheter ablation (CA). These studies included patients with paroxysmal AF and studied prognostic value of post CA I-123-mIBG parameters. Current study investigated the ability of pre CA 123-I-mIBG imaging to predict late AF recurrence in patients with persistent AF. Thus, the goal of the present study was to estimate the utility of pre-procedural cardiac 123I-mIBG scintigraphy to identify patients at risk for AF recurrence after CA. Methods. 123I-mIBG cardiac imaging was performed before CA in 82 patients with persistent AF. Patients were followed for 12 months. A blanking period of 3 months was applied. The primary endpoint of the study was AF recurrence between 3 and 12 months after ablation. Results. Multivariable analysis demonstrated that late heart-to-mediastinum ratio (H/Mlate) and washout rate (WR) were independent predictors of AF recurrence. ROC-curve analysis data showed that H/Mlate <1.6 (sensitivity 73.53 %, specificity 81.3%, AUC 0,792 , p < 0.001) and WR > 25,11 (sensitivity 70.6%, specificity 70.8.3%, AUC 0,712 , p < 0.001) indicate high probability of AF relapses during 12 months after CA. Kaplan-Meier analysis showed that the H/Mlate < 1.6, WR > 25,11 and LAD > 45 mm significantly increase the risk of AF recurrence after CA (p < 0.001, p < 0.001, p < 0.025 respectively). Conclusion. Pre CA parameters of global cardiac sympathetic activity estimated by 123I-mIBG scintigraphy are associated with late AF relapses in persistent AF patients.

Accuracy of Cardiac Innervation Scintigraphy for Mild Cognitive Impairment With Lewy Bodies

ObjectiveTo provide evidence that cardiac mIBG scintigraphy differentiates probable mild cognitive impairment with Lewy bodies (MCI-LB) from MCI due to Alzheimer’s disease (MCI-AD) we scanned patients with MCI and obtained consensus clinical diagnoses of their MCI subtype. We also performed baseline FP-CIT scans to compare the accuracy of mIBG and FP-CIT.MethodsWe conducted a prospective cohort study into the accuracy of cardiac mIBG scintigraphy in the diagnosis of MCI-LB. Follow up clinical assessment was used to diagnose MCI-AD (no core features of MCI-LB and normal FP-CIT); probable MCI-LB (2 or more core features, or 1 core feature with abnormal FP-CIT) or possible MCI-LB (1 core feature or abnormal FP-CIT). For the comparison between mIBG and FP-CIT, only core clinical features were used for diagnosis.ResultsWe recruited 95 people with mild cognitive impairment. Cardiac mIBG was abnormal in 22/37 probable and 2/15 possible MCI-LB cases and normal in 38/43 MCI-AD. The sensitivity in probable MCI-LB was 59% (95% CI 42 to 75%), specificity 88% (75 to 96%) and accuracy 75% (64 to 84%). The positive likelihood ratio was 5.1 and negative likelihood ratio 0.46. With symptom-only diagnoses, the accuracies were 79% for mIBG (95% CI: 68 to 87%) and 76% for FP-CIT (95% CI: 65 to 85%).ConclusionsCardiac mIBG appears useful in early disease, with an abnormal scan highly suggestive of MCI-LB. Validation in a multicentre setting is justified.Classification of EvidenceThis study provides Class I evidence that cardiac mIBG distinguishes MCI-LB from MCI-AD.

Whole-Body MRI and Whole Body 123I-MIBG scintigraphy: comparison in Lines and High Risk Neuroblastoma. A pilot study.

Purpose: To assess agreement between 123I-metaiodobenzylguanidine (MIBG) and Whole Body Magnetic Resonance Imaging with diffusion-weighted whole-body imaging with background body signal suppression (WB MRI-DWIBS) in High and Low, Intermediate risk neuroblastoma, a retrospective review was performed on MIBG and DWIBS paired scans acquired at diagnosis, response-to-therapy steps, after-surgery, off therapy.Methods: 80 paired MIBG and DWIBS scans were acquired for 31 patients between June 2009 and June 2019 within 30 days, without intercurrent therapy. SIOPEN Semi-quantitative scoring systems for NB with 12 body sections was applied at whole body MIBG and WB MRI-DWIBS acquired to evaluate the disease extent. We evaluated specificity, sensitivity, overall accuracy, positive predictive value (PPV) and negative predictive value (NPV) of WB MRI-DWIBS respect MIBG scintigraphy considered as gold standard, and vice versa.Results: DWIBS and MIBG images were concordant in 890 out of the 960 analyzed segments, with high agreement between the two techniques (kendal =0.85 P<0.0001 and Chi 536.5975 p<0.0001). Considering MIBG as gold standard, WB MRI-DWIBS overall accuracy was 93%, sensitivity 78%, specificity 95%, PPV 77% and NPV 96%. Otherwise, MIBG overall accuracy was 93%; sensitivity 77%; specificity 97%; VPP 78%; VPN 95%, considering DWIBS as gold standard. MIBG and WB MRI-DWIBS SIOPEN scoring resulted superimposable (Rho Spearman = 0,88, p < 0,0001).Conclusions: DWIBS and MIBG images showed very high concordance. WB MRI may represent an alternative in weak-avid MIBG tumors and for follow up assessment. An integrated imaging model is proposed for HR, Low and Intermediate Risk protocols.

Oral Cenesthopathy Proceeding Dementia with Lewy Body: a Case Report

We herein report a case of oral cenesthopathy that proceeded dementia with Lewy body (DLB). A 70-year-old female presented with oral cenesthopathy. She was diagnosed with major depression/late-onset schizophrenia and treated with paroxetine and perospirone. Subsequently, she developed severe parkinsonism. Her diagnosis changed to DLB based on clinical features and her magnetic resonance imaging, MIBG scintigraphy, and DAT scans. After tapering off paroxetine and perospirone, the patient was treated with donepezil and levodopa. The DLB symptoms, including oral cenesthopathy and parkinsonism, were relieved. This case indicates that oral cenesthopathy may occur as an early symptom of DLB.