Iodine-123 Metaiodobenzylguanidine Imaging and Carbon-11 Hydroxyephedrine Positron Emission Tomography Compared in Patients With Left Ventricular Dysfunction

Abstract

Background— Although both 123 I-metaiodobenzylguanidine ( 123 I-MIBG) imaging and 11 C-hydroxyephedrine ( 11 C-HED) positron emission tomography (PET) are used for assessing cardiac sympathetic innervation, their relationship remains unknown. The aims were to determine whether 123 I-MIBG parameters such as heart-to-mediastinum ratio (H/M) are associated with quantitative measures by 11 C-HED PET and to compare image quality, defect size, and location between 123 I-MIBG single-photon emission computed tomography (SPECT) and 11 C-HED PET. Methods and Results— Twenty-one patients (mean left ventricular ejection fraction, 39±15%) underwent 123 I-MIBG imaging and 11 C-HED PET. Early (15-minute), late (3-hour) H/M, and washout rate (WR) were calculated for 123 I-MIBG. Myocardial retention and WR was calculated for 11 C-HED. Using a polar map approach, defect was defined as the area with relative activity <60% of the maximum. Both the early ( r =0.76) and late ( r =0.84) 123 I-MIBG H/M were correlated with 11 C-HED retention. 123 I-MIBG WR was correlated with 11 C-HED WR ( r =0.57). Defect size could not be measured in 3 patients because of poor quality 123 I-MIBG SPECT, whereas 11 C-HED defect was measurable in all patients. Although defect size measured by early or late 123 I-MIBG SPECT was closely correlated with that by 11 C-HED PET (early: r =0.94; late: r =0.88), the late 123 I-MIBG overestimated defect size particularly in the inferior and septal regions. Conclusions— 123 I-MIBG H/M gives a reliable estimate of cardiac sympathetic innervation as measured by 11 C-HED PET. Furthermore, despite the close correlation in defect size, 11 C-HED PET appears to be more suitable for assessing regional abnormalities than does 123 I-MIBG SPECT.

Non-invasive imaging to identify susceptibility for ventricular arrhythmias in ischaemic left ventricular dysfunction

“…Moreover, the predictive value of late [ 123 I]MIBG defect was confirmed for appropriate ICD therapy in a more recent study 11. Although the [ 11 C]HED PET defect size is closely related to the early and late [ 123 I]MIBG SPECT defect size, it provides superior spatial resolution and potential for absolute quantification 28. The PAREPET study demonstrated that the total size of cardiac denervation predicted appropriate ICD therapy, independent of LVEF, infarct volume and hibernating myocardium.…”

Impaired Myocardial Sympathetic Innervation Is Associated with Diastolic Dysfunction in Heart Failure with Preserved Ejection Fraction: 11C-Hydroxyephedrine PET Study

“…Short-axis images were used to define a region of interest in the left ventricle. Myocardial 11 C-HED uptake was expressed using the retention index (RI [min 21 ]) that was calculated as the mean myocardial activity in the last frame (30-40 min) divided by the integral of the arterial blood time-activity curve derived from a manually placed region of interest at the basal LV cavity of valve plane (19,20). Regional PET analyses were based on the American Heart Association 17-segment model.…”

“…However, the heart-to-mediastinum ratio on early and delayed planar images and washout rate derived from 123 Imetaiodobenzylguanidine imaging were semiquantitative. In contrast, 11 C-HED is a high-specific-activity PET tracer for SNS presynaptic imaging (19) and enables better regional analysis than 123 I-metaiodobenzylguanidine (20).…”

123I-MIBG SPECT for Evaluation of Patients with Heart Failure

“…Rischpler et al (75) reported that the 131 I-MIBG uptake defect in rats matched the area of an earlier MI, whereas the mHED uptake defect was larger. However, in a direct comparison of 123 I-MIBG SPECT and mHED PET in 21 patients with left ventricular dysfunction, Matsunari et al (76) reported a high correlation between defect sizes in the 2 methods; however, late 123 I-MIBG SPECT overestimated defect sizes in the inferior and septal regions, presumably because of image quality issues caused by adjacent liver activity.…”