Comparison of the diagnostic performance of H/M ratio between early and delayed phases for Lewy body disease

Abstract

ObjectivesThe aim of the study was to compare the diagnostic performance of early-phase 123I-metaiodobenzylguanidine (MIBG) scintigraphy with that of delayed-phase imaging in Lewy body disease (LBD).MethodsA retrospective cohort study of 123I-MIBG scintigraphy was carried out in 192 patients who were suspected of having LBD. Clinical diagnosis was obtained using the UK Parkinson’s Disease Brain Bank Criteria in some cases or the third report of the Dementia with Lewy bodies Consortium in others. The participants consisted of 81 patients with LBD and 111 nondiseased patients. An injection of 111 MBq of 123I-MIBG was used. Planar images were obtained in an early phase and again in a delayed phase and the heart to mediastinum count ratio was calculated for both phases. Diagnostic performance was compared using a receiver-operator characteristic analysis. The cutoff value was chosen to maximize the Youden index. The sensitivity and specificity of each phase were calculated from the optimal cutoff value.ResultsThe heart to mediastinum ratio of the LBD group (median 1.8 and 1.45 for early and delayed phases, respectively) was significantly lower than that of the nondiseased group (median 2.93 and 3.18 for early and delayed phases, respectively). The area under the receiver-operating characteristic curve was not significantly different between the early and delayed phases (0.871 vs. 0.893; P=0.0914). Sensitivity and specificity were 80.2 and 91% for early-phase imaging (cutoff value at 2.28) and 81.5 and 95.5% (cutoff value at 1.91) for delayed-phase imaging, respectively.ConclusionThe diagnostic performance of 123I-MIBG scintigraphy was not significantly different between early-phase and delayed-phase imaging.

Time Distortion in Parkinsonism

“…In 27 PD patients and 9 PSP patients, DAT-SPECT using 123 I-2β-carbomethoxy-3β(4-iodo-phenyl) tropane ( 123 I-β-CIT) and 123 I-metaiodobenzylguanidine (MIBG) scintigraphy were also performed as part of the clinical assessment. The heart to mediastinum (H/M) ratio in the late phase of MIBG scintigraphy used to confirm the diagnosis of PD ( Maruyama et al, 2015 ) and the specific binding ratio (SBR) of DAT-SPECT averaged across the bilateral basal ganglia (average SBR) were included as clinical covariates in the multiple regression analysis below. The typical clinical features for patient inclusion are summarized in Table 2 .…”

1-23I-MIBG thyroid uptake: Implications for MIBG imaging of the heart

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] The amount of free radio iodide is the most important radiochemical impurity and must be limited to prevent excessive thyroid uptake. The amount of free iodide should be \1%-2% of total radioactivity.…”

Can early phase cardiac [123I]mIBG images be used to diagnose Lewy body disease?

“…Insufficient evidence to conclude that delayed imaging has better accuracy than early imaging does not prove that there is no difference in accuracy. One of the studies provides weak evidence, rather than no evidence, for delayed imaging being more accurate (area under the curve 0.871 early, 0.893 delayed; P = 0.091) [ 9 ]. These three studies were quite large with 453, 111 and 192 cases included.…”

“…Three recent cardiac mIBG studies in Lewy body disease carried out by separate groups [8–10] have demonstrated no significant difference between diagnostic accuracy of early or delayed imaging, suggesting that early images alone could be sufficient. Acquiring early images alone would benefit both patients and clinical departments and would also make the test much more convenient than [ 123 I] 2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (FP-CIT), which requires a 3–6 h uptake period before scanning.…”