Reproducibility of planar 123I-meta-iodobenzylguanidine (MIBG) myocardial scintigraphy in patients with heart failure

Abstract

PurposeDespite its high prognostic value, widespread clinical implementation of 123I-meta-iodobenzylguanidine (MIBG) myocardial scintigraphy is hampered by a lack of validation and standardization. The purpose of this study was to assess the reliability of planar 123I-MIBG myocardial scintigraphy in patients with heart failure (HF).MethodsPlanar myocardial MIBG images of 70 HF patients were analysed by two experienced and one inexperienced observer. The reproducibility of early and delayed heart-to-mediastinum (H/M) ratios, as well as washout rate (WR) calculated by two different methods, was assessed using the intraclass correlation coefficient (ICC) and the Bland-Altman analysis. In addition, a subanalysis in patients with a very low H/M ratio (delayed H/M ratio <1.4) was performed. The delayed H/M ratio was also assessed using fixed-size oval and circular cardiac regions of interest (ROI).ResultsIntra- and interobserver analyses and experienced versus inexperienced observer analysis showed excellent agreement for the measured early and delayed H/M ratios and WR on planar 123I-MIBG images (the ICCs for the delayed H/M ratios were 0.98, 0.96 and 0.90, respectively). In addition, the WR without background correction resulted in higher reliability than the WR with background correction (the interobserver Bland-Altman 95 % limits of agreement were −2.50 to 2.16 and −10.10 to 10.14, respectively). Furthermore, the delayed H/M ratio measurements remained reliable in a subgroup of patients with a very low delayed H/M ratio (ICC 0.93 for the inter-observer analysis). Moreover, a fixed-size cardiac ROI could be used for the assessment of delayed H/M ratios, with good reliability of the measurement.ConclusionThe present study showed a high reliability of planar 123I-MIBG myocardial scintigraphy in HF patients, confirming that MIBG myocardial scintigraphy can be implemented easily for clinical risk stratification in HF.

Phase-1 Clinical Trial Results of High-Specific-Activity Carrier-Free 123I-Iobenguane

“…This result is important for the future development of this radiotracer in subsequent clinical trials. Finally, the good reproducibility of planar measurements is concordant with a previous report of high reproducibility (22).…”

“…Verberne et al reported higher H/M ratios in 9 healthy volunteers using a no-carrier-added formulation (20); however, these higher H/M ratios could be attributed to acquisition on medium-energy collimators that reduce septal penetration and scatter of the higherenergy g photons from 123 I (21). As expected, all SPECT H/M ratios were higher than their respective planar values; however, the variability in normal SPECT H/M measurements was high, as previously reported (22). No significant difference in SPECT H/M ratios could be demonstrated when HSA MIBG and LSA MIBG were compared using this limited sample size.…”

Cardiac 123I-MIBG Imaging for Clinical Decision Making: 22-Year Experience in Japan

“…A cardiac region of interest (ROI) is set manually over the heart without overlapping lung and liver activities and with a rectangular mediastinal ROI as a background (26). The reproducibility of the HMR is good within an institution (27), although variability can be observed, depending on the selection of the ROI size and location and the operator's experience. Recently, software (smartMIBG; Fujifilm RI Pharma Co., Ltd.) became available for semiautomatic ROI settings and calculations of the HMR and WR (28).…”

123I-mIBG: Simplicity and reproducibility

“…Veltman et al demonstrated high intra-observer and inter-observer reliability, even among both experienced and inexperienced technologists. 24 A subsequent study by Pellegrino et al also demonstrated high intra-observer and inter-observer reproducibility among experienced readers. 25 The study by Bateman et al in this volume of the Journal addresses the second factor.…”