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Background The heart-to-mediastinum ratio (HMR) obtained in myocardial sympathetic innervation imaging using 123I-metaiodobenzylguanidine (MIBG) is used for heart failure or Lewy body diseases (LBD). Discovery NM/CT 670 CZT, a novel whole-body scanner, enables direct HMR measurements in planar images, in contrast to cardiac-dedicated CZT-based cameras which require specific post-processing reconstruction. We sought to investigate the clinical utility of the Discovery NM/CT 670 CZT for myocardial innervation imaging and the potential time reduction. Results Following preliminary phantom examinations, 123I-MIBG planar imaging was performed in 36 patients with suspected or known LBD to measure HMRs with a collection time of 300 s. Images for different collection times were subsequently reframed using already acquired data, and changes in HMRs were evaluated. The HMRs for patients with versus without clinically diagnosed LBD were 1.63 ± 0.08 versus 2.21 ± 0.08 at early phase (p 0.99), 100-s (ICC coefficients > 0.97), and 50-s (ICC coefficients > 0.89) images. Conclusions In planar images with a whole-body CZT-based camera, the HMRs of patients with LBD were significantly lower than those without. HMRs with the collection time of 50 s and longer showed good consistency with those of 300 s in the ICC analysis. These findings indicate a clinical utility of this novel scanner for HMR measurements and potential time reductions.

Background The heart-to-mediastinum ratio (HMR) obtained in myocardial sympathetic innervation imaging using 123I-metaiodobenzylguanidine (MIBG) is used for heart failure or Lewy body diseases (LBD). Discovery NM/CT 670 CZT, a novel whole-body scanner, enables direct HMR measurements in planar images, in contrast to cardiac-dedicated CZT-based cameras which require specific post-processing reconstruction. We sought to investigate the clinical utility of the Discovery NM/CT 670 CZT for myocardial innervation imaging and the potential time reduction. Results Following preliminary phantom examinations, 123I-MIBG planar imaging was performed in 36 patients with suspected or known LBD to measure HMRs with a collection time of 300 s. Images for different collection times were subsequently reframed using already acquired data, and changes in HMRs were evaluated. The HMRs for patients with versus without clinically diagnosed LBD were 1.63 ± 0.08 versus 2.21 ± 0.08 at early phase (p 0.99), 100-s (ICC coefficients > 0.97), and 50-s (ICC coefficients > 0.89) images. Conclusions In planar images with a whole-body CZT-based camera, the HMRs of patients with LBD were significantly lower than those without. HMRs with the collection time of 50 s and longer showed good consistency with those of 300 s in the ICC analysis. These findings indicate a clinical utility of this novel scanner for HMR measurements and potential time reductions. Electronic supplementary material The online version of this article (10.1186/s13550-019-0491-z) contains supplementary material, which is available to authorized users.

Giant cell myocarditis (GCM) is rare and often fatal. Proper diagnosis is crucial, because immunosuppressive therapy has been reported to increase the median transplant-free survival time from 3.0 to 12.3 months.1 Although endomyocardial biopsy plays an essential role in early diagnosis, it may yield false-negative results. Imaging examinations including cardiac magnetic resonance (CMR) may facilitate the diagnosis, but the associations between specific CMR findings and the clinical features and pathological findings remain unclear. We present a patient with characteristic CMR findings, with intriguing associations with the clinical features and pathological findings of the biopsy and autopsy. A 73-year-old woman presented with acute chest pain and dyspnea that had continued for 7 hours. Her medical history was unremarkable, with the exception of uveitis and dyslipidemia. Initial examination showed resting blood pressure 132/83 mm Hg, heart rate 103 bpm, and respiratory rate 17 breaths/min. She required 5 L/min of oxygen via facemask to maintain Spo2>98%. Coarse crackles were heard over both lung fields. X-ray demonstrated mild cardiomegaly with bilateral pulmonary congestion (Figure 1). Electrocardiography, which had been within normal limits 2 years previously, showed changes resembling acute myocardial infarction (Figure I in the online-only Data Supplement). Echocardiography showed global hypokinesis in the left ventricular (LV) wall, and regional akinesis in the septum and inferoseptal wall. Coronary artery angiography revealed no significant stenosis or intracoronary plaque rupture. Her serum creatinine kinase level was high at 2558 IU/L. CMR was performed on day 7. Cine-CMR showed global hypokinesis in …