The Report of ASNC-JSNC Joint Symposium in JSNC 33rd Annual Scientific Meeting.

The JSNC-ASNC joint symposium in the 33rd JSNC annual meeting was held on Jun. 24th, and we invited Prof. Mouaz H. Al-Mallah, who was the president of ASNC and requested the lecture entitled "Comparison of MPI and FFRCT". He introduced several cases and evidences reported previously, and summarized the current status of FFRCT, especially about the diagnostic performance, prognostic value, and proper use, compared to MPI.

Clinical Outcomes of Radiologic Relapse in Patients With Cardiac Sarcoidosis Under Immunosuppressive Therapies.

Although nuclear imaging can detect cardiac involvement of cardiac sarcoidosis (CS), including subclinical states, little is known about the prevalence and outcomes of radiologic relapse under prednisolone (PSL) therapy. This study aimed to investigate the clinical characteristics and outcomes in patients with radiologic relapse. A total of 80 consecutive patients with CS whose disease activity on nuclear imaging decreased at least once after initiation of immunosuppressive therapy were identified through a retrospective chart review. Radiologic relapse of CS was diagnosed using 18F-fluoro-2-deoxyglucose positron emission tomography or gallium-67 scintigraphy. Composite adverse events were defined as at least 1 of the following: all-cause death, hospitalization for heart failure, or lethal arrhythmia. During the follow-up period (median 2.9 years), radiologic relapse was observed in 31 patients (38.8% of overall patients) at 30 months (median) after immunosuppressive therapy initiation. After radiologic relapse was detected, all patients were treated with intensified immunosuppressive therapies (increasing PSL, n = 26 [83.9%], adding other immunosuppressive therapies to PSL, n = 5 [16.1%]). There were no differences in occurrences of composite adverse events in patients with and patients without radiologic relapse. Radiologic relapse under immunosuppressive therapy was observed in many patients with CS, but it was not associated with clinical outcomes under intensified immunosuppressive therapy.

Rapid response to a coronavirus disease 2019 (COVID-19) outbreak in a psychiatry hospital-Kanazawa City, Japan, March to April 2020.

A coronavirus disease 2019 (COVID-19) outbreak in a psychiatry hospital revealed specific challenges in its response such as difficulty in isolation, transfer, and identification of close contacts, suboptimal infection control practices, and shortage of personal protective equipment, which were overcome by support from the public health center and a neighboring university hospital.

Post-ISCHEMIA Trial Era: Reconsideration of the Role of Nuclear Cardiology in Patients with Chronic Coronary Artery Disease.

The International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA) trial has had a great impact on the management of chronic coronary artery disease (CAD). One of the implications of this trial is the importance of close patient follow-up. To improve patient prognosis, evaluation of the residual extent of ischemia after treatment may be important because several studies have shown a close relationship between residual ischemia and cardiac events. For this assessment, myocardial perfusion single-photon emission computed tomography (MPS) has been utilized and is almost the only modality. Among the participants in the ISCHEMIA trial, more than 10% were excluded due to the absence of obstructive CAD. The pathophysiology of ischemia without non-obstructive coronary artery disease (INOCA) is gaining recognition; however, diagnosis is difficult, except for the assessment of myocardial flow reserve (MFR). Myocardial perfusion positron emission tomography (PET) is the most common modality for noninvasive evaluation of MFR; however, its availability in Japan is limited. For a breakthrough in this situation, a novel gamma camera with a cadmium zinc telluride (CZT) semiconductor might be one of the solutions that enables the evaluation of MFR with a commercially available perfusion tracer, similar to PET. Another solution is a novel PET tracer with a longer half-life. Clinical trials with 18F labeled perfusion agents have been initiated in Japan, and in a few years, delivery of this perfusion tracer will result in more frequent and easier assessment of MFR.

Clinical Validation of Japanese Normal Myocardial Perfusion Imaging Databases Using Semi-conductor Gamma Camera (D-SPECT): Japanese Society of Nuclear Cardiology Working Group Reports.

Objective: A working group (WG) of the Japanese Society of Nuclear Cardiology (JSNC) determined Japanese normal databases of myocardial perfusion single-photon emission computed tomography (SPECT) on semi-conductor gamma camera (D-SPECT), and the aim of this study was to validate its clinical utility. Materials and methods: The normal myocardial perfusion SPECT (MPS) databases of Japanese patients in the 201Tl stress/redistribution protocol (201Tl protocol), 99mTc stress/rest or rest/stress protocol (99mTc protocol), and rest 99mTc/stress 201Tl simultaneous acquisition dual-isotope protocol (SDI protocol) were created by JSNC WG. The WG collected clinical cases for the 201Tl protocol (male/female [m/f], 8/8), 99mTc protocol (m/f, 9/7), and SDI protocol (m/f, 10/10) from WG participating hospitals. Four WG members read those clinical cases on a 17-segment and 5-point scale (0-4). Using the most frequent values as the score for each segment, weighted κ values were calculated with the scores obtained from quantitative perfusion software (QPS). Results: Weighted κ values were as follows; 201Tl stress/female, 0.77; 201Tl rest/female, 0.74; 201Tl stress/male, 0.81; 201Tl rest/male, 0.68; 99mTc stress/female, 0.77; 99mTc rest/female, 0.62; 99mTc stress/male, 0.77; 99mTc rest/male, 0.75; SDI stress/female, 0.87; SDI rest/female, 0.82; SDI stress/male, 0.87; SDI rest/male, 0.85. Conclusions: The diagnostic accuracy of Japanese MPS normal databases on D-SPECT were comparable with nuclear cardiology expert reading and further clinical applications are expected.

Patient positioning during pediatric cardiothoracic computed tomography using a high-resilience pad system and pre-scan measurement of chest thickness.

Patient positioning at the isocenter of the CT gantry is important for optimizing image quality and radiation dose, but accurate positioning is challenging in pediatric patients. We evaluated whether the high-resilience pad and pre-scan measurement of chest thickness allow accurate positioning in pediatric patients with congenital heart disease. Sixty-seven patients aged 7 years or younger who underwent cardiothoracic CT were enrolled. The ideal table height, defined as the position at which the scanner's and patient's isocenters coincided, was determined by radiographers either manually (manual group) or based on the pad's and chest's thickness (calculated group). The distance between the two isocenters and image quality were evaluated. The calculated group demonstrated smaller isocenter distance and standard deviation (distance: 0.2 ± 5.8 mm vs. - 8.3 ± 11.6 mm, p < 0.01; absolute value: 4.1 [1.9-8.0] mm vs. 12.3 [5.1-16.3] mm, p < 0.01), and higher signal-to-noise ratio (SNR) and dose-normalized SNR (SNRD) in the descending aorta than the manual group (SNR: 39.8 [31.0-53.7] vs. 31.9 [28.9-36.6], p = 0.048, SNRD: 39.8 [31.0-53.7] vs. 31.9 [28.9-36.6], p = 0.04). The system allowed for more accurate positioning in pediatric cardiothoracic CT, yielding higher image quality.

Retrograde penetration pacing into the conduction system as an alternative approach of his-bundle pacing: Retrograde penetration pacing into the conduction system.

BACKGROUND: The optimal right ventricular (RV) pacing site during pacemaker implantation is still unclear due to left ventricular (LV) dyssynchrony by traditional RV pacing. His-bundle (HIS) pacing has achieved narrow QRS and maintained LV synchrony but high failure rate. RV septal pacing occasionally has QRS waveform with wide and narrow component in the early and late phase, respectively, and maintains LV synchrony, reflecting the normal conduction system. We aimed to define this QRS waveform as retrograde penetration pacing into the conduction system (RPP-CS) and compared its effect on LV synchrony as an alternative approach of HIS pacing. METHODS AND RESULTS: We enrolled 42 patients with atrio ventricular block (AVB) or bradycardia atrial fibrillation (AF) requiring pacemaker implantation (RPP-CS, n = 27; no RPP-CS, n = 15). Baseline characteristics were similar between the groups. RPP-CS was observed in 96% and 26% of the RV septum and apex area, respectively. RPP-CS had a significantly shorter QRS width (p < 0.001). The frequency of maintaining LV synchrony was significantly higher in RPP-CS (67% vs. 20%, p = 0.003). The QRS interval's optimal cut-off value during RPP-CS was 132 ms for prediction of LV synchrony (sensitivity 83%, specificity 89%, positive predictive value 94%, and negative predictive value 73%). During RPP-CS, shorter QRS intervals (QRS ≤ 132 ms) had better postoperative LV ejection fraction than longer intervals (p < 0.001). CONCLUSIONS: RPP-CS, especially with short QRS intervals (≤132 ms), had a high frequency of LV synchrony, maintained postoperative cardiac function, and may be an adequate first-line RV pacing site strategy for AVB or bradycardia AF as an alternative approach of HIS pacing.

Unusual Overlapping Cardiac Sarcoidosis and Long-QT Type 3 Induced Ventricular Fibrillation.

A 54-year-old woman had been resuscitated after ventricular fibrillation and her electrocardiogram showed a QT prolongation (QTc=510 ms), and genetic screening revealed a missense variant, R1644C, in the SCN5A gene. She was therefore diagnosed with congenital long-QT syndrome (LQTS) type 3. However, the patient had left ventricular dysfunction, and based on the findings of cardiac magnetic resonance imaging, positron emission tomography and pathological examinations, she was diagnosed with cardiac sarcoidosis. Although both are rare diseases, their overlapping presence in this case may have led to an increased cardiovascular risk compared with either alone. Thus, not only genetic but comprehensive clinical examinations are important for making a correct diagnosis.

Clinical impact of left ventricular paced conduction disturbance in cardiac resynchronization therapy.

BACKGROUND: Myocardial scarring is associated with nonresponse to cardiac resynchronization therapy (CRT) and conduction delay. Little is known about the significance and cause of left ventricular (LV) paced conduction disturbance (LPCD). OBJECTIVE: The purpose of this study was to investigate the clinical impact of paced interlead electrical delay and the difference in each conduction time from LV pace to right ventricular (RV) sense (LVp-RVs) and from RV pace to LV sense (RVp-LVs) [(LVp-RVs) - (RVp-LVs)], in CRT. METHODS: Among 137 patients who underwent CRT implantation, LVp-RVs and RVp-LVs were measured intraoperatively. The relationships between [(LVp-RVs) - (RVp-LVs)] and perfusion defects on myocardial perfusion single photon emission computed tomography (SPECT) imaging or [(LVp-RVs) - (RVp-LVs)] and clinical outcomes were assessed. RESULTS: After CRT implantation, 81 patients (59%) responded to CRT. [(LVp-RVs) - (RVp-LVs)] was significantly longer in nonresponders than in responders (9.7 ± 47.3 ms vs -4.5 ± 33.2 ms; P = .041). Patients with LPCD [(LVp-RVs) > (RVp-LVs)] had higher perfusion defects in the anterolateral region (2.7 ± 2.7 vs 1.1 ± 1.6; P = .0015) on SPECT. Multivariate analysis showed that LPCD was the independent predictor of nonresponse to CRT (odds ratio 0.40; 95% confidence interval [CI] 0.17-0.90; P = .026). During median follow-up of 2.3 years (interquartile range 1.3-5.5), LPCD was the independent predictor of cardiac death and/or heart failure hospitalization in multivariate analysis (hazard ratio 2.04; 95% CI 1.19-3.55; P = .010). CONCLUSION: LPCD could predict nonresponse to CRT and poor outcome. Further intervention, such as adjustment of pacing timing or multipoint/site pacing, may be needed in such patients.

Assessing the Clinical Value of Myocardial Perfusion SPECT in Cardiac Sarcoidosis with Diffuse Myocardial 18F-FDG Uptake.

Background: Myocardial 18F-fluorodeoxyglucose (18F-FDG) uptake is a sign of active inflammation in patients with cardiac sarcoidosis (CS) under the correct circumstance. However, even under the proper preparation, diffuse myocardial 18F-FDG uptake is frequently observed in the failing heart and misleads the CS disease activity. The aim of this study was to establish the diagnostic value of resting myocardial perfusion single photon emission computed tomography (SPECT) for assessing CS disease activity in patients with diffuse myocardial 18F-FDG uptake. Methods: We examined 39 patients with either histologically or clinically proven CS. All patients underwent 18F-FDG positron emission tomography (PET) and resting 99mTc-SPECT. The presence of perfusion-metabolic mismatch was evaluated with generating polar maps of 18F-FDG PET and 99mTc-SPECT images. Results: Increased myocardial 18F-FDG uptake was observed in 33 (85%) of 39 patients. Focal 18F-FDG uptake was detected in 16 patients and diffuse 18F-FDG uptake was seen in 17 patients. Brain natriuretic peptide (BNP) levels were significantly higher in patients with diffuse 18F-FDG uptake than those with focal 18F-FDG uptake (p=0.002). With comparing polar maps of 18F-FDG PET and 99mTc-SPECT images, 8 of 16 patients with diffuse 18F-FDG uptake and myocardial perfusion defects demonstrated perfusion-metabolic mismatch which represented active inflammatory lesions in CS. Conclusions: Simultaneous evaluation of myocardial 18F-FDG PET and 99mTc-SPECT by polar map analysis provides more relevant information for assessing disease activity in CS than 18F-FDG PET images alone. Perfusion-metabolic mismatch might indicate latent active inflammation in CS patients with diffuse myocardial 18F-FDG uptake, who had advanced heart failure.

Role of Gallium-SPECT-CT in the Management of Patients With Ventricular Assist Device-Specific Percutaneous Driveline Infection.

BACKGROUND: Percutaneous driveline infection is a major complication of left ventricular assist device (LVAD). This study evaluated the role of gallium-67 single-photon emission computed tomography (Ga-SPECT)-CT in LVAD-specific percutaneous driveline infection. METHODS: Thirty-six patients with implantable continuous-flow LVAD, who underwent Ga-SPECT-CT to evaluate percutaneous driveline infections, were enrolled and divided into uptake and no-uptake groups based on tracer concentration uptake on Ga-SPECT-CT. Primary outcomes were surgical intervention and readmission for driveline infection. RESULTS: Twenty-two patients had uptake on Ga-SPECT-CT. No significant differences were noted in patient characteristics, wound appearance, or laboratory results. The prevalence of positive skin culture at the driveline exit site (DLES), and usage and duration of antibiotics did not differ. However, the uptake group had higher 1-year event rates (surgical intervention: 39% vs 0%, P = .019; readmission: 74% vs 6.9%, P = .0016). In addition to positive skin culture at DLES and short duration of antibiotic therapy, uptake on Ga-SPECT-CT was a risk factor for surgical intervention (odds ratio 9.00; P = .018) and readmission (odds ratio 7.86; P = .0051). CONCLUSIONS: Ga-SPECT-CT could be one of the clinical modalities for guiding the treatment of driveline infection in patients with a LVAD.

Risk factors of non-sustained ventricular tachycardia by technetium-perfusion imaging in patients with coronary artery lesions caused by Kawasaki disease.

BACKGROUND: Sudden death can occur in some patients with non-sustained ventricular tachycardia (NSVT) after myocardial infarction (MI) in those with coronary artery lesions (CAL) caused by Kawasaki disease (KD). The aim of this study was to determine the risk factors for NSVT in the late period after KD by technetium-99m-tetrofosmin myocardial perfusion imaging (MPI). METHODS: We retrospectively analyzed the relation between the appearance of NSVT and the findings in MPI single-photon-emission computed tomography (SPECT) in 75 patients (55 males and 20 females) who had had CAL caused by KD. All the patients had undergone MPI and 24-h Holter electrocardiogram at the same time between 2003 and 2012. The age at MPI ranged from 2 to 44 years (median 19 years), and the time from the onset of KD to MPI ranged from 1 to 44 years (median 18 years). We evaluated extent score (ES), summed rest score (SRS), summed stress score (SSS), summed difference score (SDS), and left ventricular ejection fraction (LVEF) by quantitative gated SPECT software. We analyzed which factors related to NSVT using multivariate logistic regression. Further, we calculated the cut-off point for NSVT using receiver operating characteristic curve. RESULTS: The affecting factors were ES (OR, 0.63, 95%CI, 0.35-0.92, p=0.013) and the interval from the onset of KD to MPI (OR, 0.82, 95%CI, 0.69-0.96, p=0.004). The cut-off points for ES and the interval from the onset of KD were 11% (AUC, 0.931, p<0.001) and 18 years (AUC, 0.732, p=0.007), respectively. CONCLUSIONS: ES is the strongest parameter for predicting NSVT in the late period. In patients with post-KD, adolescence and young adults with ES ≥11% are at risk of fatal ventricular arrhythmia.

Prognostic impact of reducing myocardial ischemia identified using ECG-gated myocardial perfusion SPECT in Japanese patients with coronary artery disease: J-ACCESS 4 study.

AIM: Whether myocardial ischemia identified using myocardial perfusion imaging (MPI) can be an alternative target of coronary revascularization to reduce the incidence of cardiac events remains unclear. METHODS AND RESULTS: This multicenter, prospective cohort study aimed to clarify the prognostic impact of reducing myocardial ischemia. Among 494 registered patients with possible or definite coronary artery disease (CAD), 298 underwent initial pharmacological stress 99mTc-tetrofosmin MPI before, and eight months after revascularization or medical therapy, and were followed up for at least one year. Among these, 114 with at least 5% ischemia at initial MPI were investigated. The primary endpoints were cardiac death, non-fatal myocardial infarction and hospitalization for heart failure. Ischemia was reduced ≥5% in 92 patients. Coronary revascularization reduced ischemia (n = 89) more effectively than medical therapy (n = 25). Post-stress cardiac function also improved after coronary revascularization. Ejection fraction significantly improved at stress (61.0% ±â€¯10.7% vs. 65.4% ±â€¯11.3%; p < 0.001) but not at rest (67.1% ±â€¯11.3% vs. 68.3% ±â€¯11.6%; p = 0.144), among patients who underwent revascularization. Rates of coronary revascularization and cardiac events among the 114 patients were significantly higher (13.6%, p = 0.035) and lower (1.1% p = 0.0053), respectively, in patients with, than without ≥5% ischemia reduction. Moreover, patients with complete resolution of ischemia at the time of the second MPI had a significantly better prognosis. CONCLUSIONS: Reducing ischemia by ≥5% and the complete resolution of ischemia could improve the prognosis of patients with stable CAD.

Comparison Between Prone and Upright Imaging of the Inferior Wall Using 201TlCl Myocardial Perfusion SPECT.

Because it suppresses attenuation artifacts from the diaphragm, prone SPECT is suitable for evaluating the cardiac inferior wall. A solid-state dedicated cardiac camera allows upright imaging, which can also be used to avoid attenuation artifacts from the diaphragm. We compared prone and upright imaging for inferior wall evaluation using 201TlCl myocardial perfusion SPECT (MPS). Methods: The study targeted 45 patients. The prone imaging group included 23 subjects who underwent additional prone imaging because supine imaging indicated that the inferior wall had reduced uptake. The upright imaging group included 22 subjects who, in the past, had shown reduced uptake in the inferior wall during supine imaging. Using the MPS stress images and analysis software, we created a polar map showing the incorporation of the radioisotope throughout the whole of the myocardium; this polar map was then classified into 17 segments. The percentage uptake ratios of the inferior/anterior wall were calculated for the prone and upright acquisitions. These ratios were used as the ratio of percentage uptake in each segment of the anterior wall to percentage uptake in each segment of the inferior wall. In addition, 6 reviewers visually evaluated the uniformity within the inferior wall for both the prone and the upright imaging. Results: There was a significant difference in percentage uptake ratios between the prone and upright images in segments 4/1 (basal inferior/basal anterior; P < 0.05), 11/12 (mid inferolateral/mid anterolateral; P < 0.001), and 15/13 (apical inferior/apical anterior; P < 0.05). There were no significant differences between the prone and upright images in visual evaluations of uniformity within the inferior wall. Conclusion: In comparison with upright imaging, prone imaging has a higher rate of suppression of attenuation artifacts from the diaphragm. However, this difference does not seem to affect the images visually. Therefore, upright and prone imaging can be used interchangeably to evaluate the inferior wall.

Diagnostic accuracy of an artificial neural network compared with statistical quantitation of myocardial perfusion images: a Japanese multicenter study.

PURPOSE: Artificial neural networks (ANN) might help to diagnose coronary artery disease. This study aimed to determine whether the diagnostic accuracy of an ANN-based diagnostic system and conventional quantitation are comparable. METHODS: The ANN was trained to classify potentially abnormal areas as true or false based on the nuclear cardiology expert interpretation of 1001 gated stress/rest 99mTc-MIBI images at 12 hospitals. The diagnostic accuracy of the ANN was compared with 364 expert interpretations that served as the gold standard of abnormality for the validation study. Conventional summed stress/rest/difference scores (SSS/SRS/SDS) were calculated and compared with receiver operating characteristics (ROC) analysis. RESULTS: The ANN generated a better area under the ROC curves (AUC) than SSS (0.92 vs. 0.82, p < 0.0001), indicating better identification of stress defects. The ANN also generated a better AUC than SDS (0.90 vs. 0.75, p < 0.0001) for stress-induced ischemia. The AUC for patients with old myocardial infarction based on rest defects was 0.97 (0.91 for SRS, p = 0.0061), and that for patients with and without a history of revascularization based on stress defects was 0.94 and 0.90 (p = 0.0055 and p < 0.0001 vs. SSS, respectively). The SSS/SRS/SDS steeply increased when ANN values (probability of abnormality) were >0.80. CONCLUSION: The ANN was diagnostically accurate in various clinical settings, including that of patients with previous myocardial infarction and coronary revascularization. The ANN could help to diagnose coronary artery disease.

Criteria for the addition of prone imaging to myocardial perfusion single-photon emission computed tomography for inferior wall.

OBJECTIVE: Myocardial perfusion single-photon emission computed tomography (SPECT) is occasionally suspected to generate images that represent either ischemia or infarction for the inferior wall [right coronary artery (RCA) disease] or attenuation artifacts because of the diaphragm. We often encounter this. The application of prone imaging is advantageous in the differentiation of RCA disease because of attenuation artifacts. If decreased accumulation of radioisotopes is observed at the site with either RCA disease or attenuation artifacts, then a criterion that enables the addition of prone imaging should be implemented. Then, we evaluated sites where RCA disease and attenuation artifacts would likely appear and investigated the threshold of decreased accumulation that enables utilization of prone imaging. PATIENTS AND METHODS: The patients in this study were divided into two groups: group A (20 patients) suspected to have attenuation artifacts because of the diaphragm and group B (14 patients) with RCA disease. Additional evaluation by prone imaging was performed in all patients. We utilized a 20-segment quantitative perfusion SPECT polar map in the supine and prone positions to compare the percentage increase in Thallium chloride (Tl) in both groups. We then investigated the percent uptake (%uptake) value of decreased accumulation in the inferior wall for the addition of prone imaging. RESULTS: The highest %uptake was present in segments 3, 4, 5, and 10 in group A after the prone imaging. Detection of attenuation artifacts from the diaphragm was easy in segments 3, 4, 5, and 10, and we set the %uptake threshold at 62, 61, 71, and 76%, respectively, in the supine position for the addition of prone imaging. CONCLUSION: A decrease of the %uptake in segments 3, 4, 5, and 10 after supine imaging is presumed to result from attenuation artifact or RCA disease. We established evaluation criteria for the addition of prone imaging in patients with decreased accumulation in the inferior wall during supine imaging.

Optimal injected dose ratio of a very rapid 1-day protocol of myocardial perfusion imaging with cadmium-zinc-telluride single-photon emission tomography: simulation and phantom study.

OBJECTIVE: Cadmium-zinc-telluride detectors enable shorter acquisition durations in myocardial perfusion imaging (MPI), but the time interval of sequential scanning is still unchanged in clinical practice. We designed a very rapid 1-day protocol of MPI using cadmium-zinc-telluride single-photon emission tomography and evaluated the optimal dose ratio between two scanning acquisitions by means of simulations and phantom experiments. METHODS: We intended to perform a 1-day MPI within 140 min and simulate radioactivities in the second scan under various injected dose ratios. To apply this, a cardiac phantom was scanned with various radioactivities and scans were compared with a reference scan with the ideal tracer concentrations. RESULTS: In the stress-first protocol, the dose ratio 1 : 5 was enough to show the same regional percentage uptake compared with the reference. However, in the rest-first protocol, the regional percentage uptakes were higher than those of the reference image even with a 1 : 6 dose ratio. CONCLUSION: The injected dose ratio 1 : 5 is optimal in a stress-first rapid 1-day protocol. The rest-first protocol is not appropriate because a dose ratio greater than 1 : 6 is required to withdraw shine-through artifacts.