Metaiodobenzylguanidine scintigraphy of cardiac sympathetic innervation

Teresińska, Anna

doi:10.5603/nmr-18732

Cited by 11 publications

(6 citation statements)

References 62 publications

(26 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These variable and contradictory results in vasovagal syncope suggest the need for considerably more work in this area before definitive conclusions can be drawn. In contrast, sympathetic neuroimaging using 123-I-MIBG scanning has been used extensively in cardiac risk evaluation, in particular in the prognosis of cardiac failure and related risks of ventricular tachyarrhythmias in such patients [ 14 ]. It also has a role in the investigation of the alpha-synucleinopathies, providing a reliable method of identifying patients with Parkinson’s disease versus control subjects and those with multiple systems atrophy [ 15 , 16 ].…”

Section: Discussionmentioning

confidence: 99%

Cardiac Iodine-123-Meta-Iodo-Benzylguanidine Uptake in Carotid Sinus Hypersensitivity

et al. 2015

View full text Add to dashboard Cite

BackgroundCarotid sinus syndrome is the association of carotid sinus hypersensitivity with syncope, unexplained falls and drop attacks in generally older people. We evaluated cardiac sympathetic innervation in this disorder in individuals with carotid sinus syndrome, asymptomatic carotid sinus hypersensitivity and controls without carotid sinus hypersensitivity.MethodsConsecutive patients diagnosed with carotid sinus syndrome at a specialist falls and syncope unit were recruited. Asymptomatic carotid sinus hypersensitivity and non-carotid sinus hypersensitivity control participants recruited from a community-dwelling cohort. Cardiac sympathetic innervation was determined using Iodine-123-metaiodobenzylguanidine (123-I-MIBG) scanning. Heart to mediastinal uptake ratio (H:M) were determined for early and late uptake on planar scintigraphy at 20 minutes and 3 hours following intravenous injection of 123-I-MIBG.ResultsForty-two subjects: carotid sinus syndrome (n = 21), asymptomatic carotid sinus hypersensitivity (n = 12) and no carotid sinus hypersensitivity (n = 9) were included. Compared to the non- carotid sinus hypersensitivity control group, the carotid sinus syndrome group had significantly higher early H:M (estimated mean difference, B = 0.40; 95% confidence interval, CI = 0.13 to 0.67, p = 0.005) and late H:M (B = 0.32; 95%CI = 0.03 to 0.62, p = 0.032). There was, however, no significant difference in early H:M (p = 0.326) or late H:M (p = 0.351) between the asymptomatic carotid sinus hypersensitivity group and non- carotid sinus hypersensitivity controls.ConclusionsCardiac sympathetic neuronal activity is increased relative to age-matched controls in individuals with carotid sinus syndrome but not those with asymptomatic carotid sinus hypersensitivity. Blood pressure and heart rate measurements alone may therefore represent an over simplification in the assessment for carotid sinus syndrome and the relative increase in cardiac sympathetic innervation provides additional clues to understanding the mechanisms behind the symptomatic presentation of carotid sinus hypersensitivity.

show abstract

Section: Discussionmentioning

confidence: 99%

Cardiac Iodine-123-Meta-Iodo-Benzylguanidine Uptake in Carotid Sinus Hypersensitivity

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Radioiodinated meta -iodobenzylguanidine (MIBG) [1], originally developed as an adrenomedullary imaging agent [2], has been widely used for imaging the pathophysiology of the heart [3] and in the diagnosis and therapy of neuroendocrine tumors [4]. For diagnostic applications, planar scintigraphy and single photon emission computed tomography (SPECT) are the modalities that are often used in tandem with [ 131 I]MIBG and [ 123 I]MIBG, respectively.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and evaluation of 4-[18F]fluoropropoxy-3-iodobenzylguanidine ([18F]FPOIBG): A novel 18F-labeled analogue of MIBG

Vaidyanathan

McDougald

Koumarianou

et al. 2015

Nuclear Medicine and Biology

View full text Add to dashboard Cite

Introduction Radioiodinated meta-iodobenzylguanidine (MIBG), a norepinephrine transporter (NET) substrate, has been extensively used as an imaging agent to study the pathophysiology of the heart and for the diagnosis and treatment of neuroendocrine tumors. The goal of this study was to develop an 18F-labeled analogue of MIBG that like MIBG itself could be synthesized in a single radiochemical step. Towards this end, we designed 4-fluoropropoxy-3-iodobenzylguanidine (FPOIBG). Methods Standards of FPOIBG and 4-fluoropropoxy-3-bromobenzylguanidine (FPOBBG) as well as their tosylate precursors for labeling with 18F, and a tin precursor for the preparation of radioiodinated FPOIBG were synthesized. Radiolabeled derivatives were synthesized by nucleophilic substitution and electrophilic iododestannylation from the corresponding precursors. Labeled compounds were evaluated for NET transporter recognition in in vitro assays using three NET-expressing cell lines and in biodistribution experiments in normal mice, with all studies performed in a paired-label format. Competitive inhibition of [125I]MIBG uptake by unlabeled benzylguanidine compounds was performed in UVW-NAT cell line to determine IC50 values. Results [18F]FPOIBG was synthesized from the corresponding tosylate precursor in 5.2 ± 0.5% (n = 6) overall radiochemical yields starting with aqueous fluoride in about 105 min. In a paired-label in vitro assay, the uptake of [18F]FPOIBG at 2 h was 10.2 ± 1.5%, 39.6 ± 13.4%, and 13.3 ± 2.5%, in NET-expressing SK-N-SH, UVW-NAT, and SK-N-BE(2c) cells, respectively, while these values for [125I]MIBG were 57.3 ± 8.1%, 82.7 ± 8.9%, and 66.3 ± 3.6%. The specificity of uptake of both tracers was demonstrated by blocking with desipramine. The 125I-labeled congener of FPOIBG gave similar results. On the other hand, [18F]FPOBBG, a compound recently reported in the literature, demonstrated much higher uptake, albeit less than that of co-incubated [125I]MIBG. IC50 values for FPOIBG were higher than that obtained for MIBG and FPOBBG. Unlike the case with [18F]FPOBBG, the heart uptake [18F]FPOIBG in normal mice was significantly lower than that of MIBG. Conclusion Although [18F]FPOIBG does not appear to warrant further consideration as an 18F-labeled MIBG analogue, analogues wherein the iodine in it is replaced with a chlorine, fluorine or hydrogen might be worth pursuing. Advances in knowledge and implications for patient care An 18F-labeled analogue of the well-known radiopharmaceutical MIBG could have significant impact, potentially improving imaging of NET related disease in cardiology and in the imaging of neuroendocrine tumors. Although 18F-labeled analogues of MIBG have been reported including LMI1195, we undertook this work hypothesizing that based on its greater structural similarity to MIBG, FPOIBG might be a better analogue than LMI1195.

show abstract

“…All animals except pig 3 showed a mild reduction of radiotracer uptake in the apex. This phenomenon has been previously described in clinical studies on humans (8). In addition, and considering the smaller myocardial mass in pigs than in humans, it is likely that the physiologic thinning of the apex may determine, through the partial-volume effect, an apparent reduction in regional myocardial uptake of the radiotracer.…”

Section: Left Ventricular Perfusion/functionmentioning

confidence: 55%

Dynamic 3D Analysis of Myocardial Sympathetic Innervation: An Experimental Study Using ¹²³I-MIBG and a CZT Camera

et al. 2015

View full text Add to dashboard Cite

Data on the in vivo myocardial kinetics of 123 I-metaiodobenzylguanidine ( 123 I-MIBG) are scarce and have always been obtained using planar acquisitions. To clarify the normal kinetics of 123 I-MIBG in vivo over time, we designed an experimental protocol using a 3-dimensional (3D) dynamic approach with a cadmium zinc telluride (CZT) camera. Methods: We studied 6 anesthetized pigs (mean body weight, 37 ± 4 kg). Left ventricular myocardial perfusion and sympathetic innervation were assessed using 99m Tc-tetrofosmin (26 ± 6 MBq), 123 I-MIBG (54 ± 14 MBq), and a CZT camera. A normal perfusion/function match on gated SPECT was the inclusion criterion. A dynamic acquisition in list mode started simultaneously with the bolus injection of 123 I-MIBG, and data were collected every 5 min for the first 20 min and then at acquisition steps of 30, 60, 90, and 120 min. Each step was reconstructed using dedicate software and reframed (60 s/frame). On the reconstructed transaxial slice that best showed the left ventricular cavity, regions of interest were drawn to obtain myocardial and blood pool activities. Myocardial time-activity curves were generated by interpolating data between contiguous acquisition steps, corrected for radiotracer decay and injected dose, and fitted to a bicompartmental model. Time to myocardial maximum signal intensity (MSI), MSI value, radiotracer retention index (RI, myocardial activity/blood pool integral), and washout rate were calculated. The mediastinal signal was measured and fitted to a linear model. Results: The myocardial MSI of 123 I-MIBG was reached within 5.57 ± 4.23 min (range, 2-12 min). The mean MSI was 0.426% ± 0.092%. Myocardial RI decreased over time and reached point zero at 176 ± 31 min (range, 140-229 min). The ratio between myocardial and mediastinal signal at 15 and 125 min and extrapolated at 176 and 4 h was 5.45% ± 0.61%, 4.33% ± 1.23% (not statistically significant vs. 15 min), 3.95% ± 1.46% (P , 0.03 vs. 125 min), and 3.63% ± 1.64% (P , 0.03 vs. 176 min), respectively. Mean global washout rate at 125 min was 15% ± 14% (range, 0%-34%), and extrapolated data at 176 min and 4 h were 18% ± 18% (range, 0.49%-45%) and 25% ± 23% (range, 1.7%-56.2%; not statistically significant vs. 176 min), respectively. Conclusion: 3D dynamic analysis of 123 I-MIBG suggests that myocardial peak uptake is reached more quickly than previously described. Myocardial RI decreases over time and, on average, is null about 3 h after injection. The combination of an early peak and variations in delayed myocardial uptake could result in a wide physiologic range of washout rates. Mediastinal activity appears to be constant over time and significantly lower than previously described in planar studies, resulting in a higher heart-to-mediastinum ratio.

show abstract

Metaiodobenzylguanidine scintigraphy of cardiac sympathetic innervation

Cited by 11 publications

References 62 publications

Cardiac Iodine-123-Meta-Iodo-Benzylguanidine Uptake in Carotid Sinus Hypersensitivity

Cardiac Iodine-123-Meta-Iodo-Benzylguanidine Uptake in Carotid Sinus Hypersensitivity

Synthesis and evaluation of 4-[18F]fluoropropoxy-3-iodobenzylguanidine ([18F]FPOIBG): A novel 18F-labeled analogue of MIBG

Dynamic 3D Analysis of Myocardial Sympathetic Innervation: An Experimental Study Using ¹²³I-MIBG and a CZT Camera

Contact Info

Product

Resources

About

Metaiodobenzylguanidine scintigraphy of cardiac sympathetic innervation

Cited by 11 publications

References 62 publications

Cardiac Iodine-123-Meta-Iodo-Benzylguanidine Uptake in Carotid Sinus Hypersensitivity

Cardiac Iodine-123-Meta-Iodo-Benzylguanidine Uptake in Carotid Sinus Hypersensitivity

Synthesis and evaluation of 4-[18F]fluoropropoxy-3-iodobenzylguanidine ([18F]FPOIBG): A novel 18F-labeled analogue of MIBG

Dynamic 3D Analysis of Myocardial Sympathetic Innervation: An Experimental Study Using 123I-MIBG and a CZT Camera

Contact Info

Product

Resources

About

Dynamic 3D Analysis of Myocardial Sympathetic Innervation: An Experimental Study Using ¹²³I-MIBG and a CZT Camera