Cardiac Scintigraphy Research Articles

Current Practices in Amyloidosis Imaging with Cardiac Scintigraphy.

Current Practices in Amyloidosis Imaging with Cardiac Scintigraphy.

Long-term safety and efficacy of antibody ALXN2220 for depletion of cardiac amyloid transthyretin: results of treatment beyond 12 months in the open-label extension of study NI006-101

Abstract Introduction ALXN2220 (formerly NI006) is an investigational human monoclonal antibody in development for the treatment of transthyretin-mediated amyloid cardiomyopathy (ATTR-CM). ALXN2220 is designed to deplete cardiac amyloid transthyretin (ATTR) deposits in patients with ATTR-CM on top of standard of care. Data from the first-in-human, ascending dose study NI006-101 show that ALXN2220 is safe and well tolerated. A reduction of surrogate markers of cardiac amyloid load and cardiac biomarkers was observed in participants receiving doses of ≥ 10mg/kg of ALXN2220 over a period of 12 months of treatment. Purpose Long-term safety, tolerability and efficacy of ALXN2220 treatment beyond 12 months was studied in a prolonged Open-Label Extension (OLE) of the NI006-101 study. Methods Participants completing 12 months in dose cohorts ≤ 30 mg/kg were allowed to receive additional 6 to 12 monthly open-label ALXN2220 infusions with up-titration of all participants to 30 mg/kg. Cardiac biomarkers were measured centrally, and serial cardiac imaging was performed with echocardiography and cardiac MRI or scintigraphy. Results Out of 27 participants completing 12 months, 23 (18 ATTRwt, all male, median age 70 years at screening (range 28-83)) continued treatment in the prolonged OLE. Median number of infusions of ALXN2220 received and median time followed across the full study were 20 infusions (range 11-24) and 125 weeks (range 83-153). Overall adherence to treatment was high in the prolonged OLE, 97% of planned infusions administered, 87% of participants received all planned doses. No severe or serious adverse events were considered related to ALXN2220 or resulted in the discontinuation during OLE, and no events of cytokine release syndrome or thrombocytopenia were observed. None of the participants had anti-drug antibodies throughout the trial. Cardiac biomarkers (NT-proBNP, troponin) and cardiac imaging indicated continued treatment effects beyond 12 months and supported the up-titration of participants who previously received lower doses of ALXN2220. Conclusions Up-titration and long-term treatment at a dose level of 30 mg/kg in the OLE was safe and well tolerated, with overall good adherence to treatment. Cardiac imaging and cardiac biomarker data indicated continued treatment effects beyond 12 months and supported the up-titration of patients to 30 mg/kg.

The Utility of Baseline Characteristics and [123I]MIBG Cardiac Adrenergic System Scintigraphy in Qualifying Patients with Post-Infarction Heart Failure for Implantable Cardioverter-Defibrillator (ICD) Placement.

Background: Post-infarction heart failure with reduced ejection fraction (HFrEF) patients often face persistent risks of sudden cardiac arrest leading to sudden cardiac death. While implanting a cardioverter-defibrillator (ICD) can enhance prognosis, complications and costs limit its widespread use. Current patient qualification criteria, relying on imperfect parameters, require refinement. The impairment of the cardiac adrenergic system in heart failure is associated with ventricular arrhythmias. The goal of the study was to assess the utility of cardiac adrenergic system scintigraphy in qualifying patients for ICD placement. Methods: In this prospective study of 85 post-infarction HFrEF patients at a single center, clinical assessments, laboratory tests, echocardiography, [123I]MIBG scintigraphy, and ICD implantation were performed. Scintigraphy involved planar chest images and evaluating the heart-to-mediastinum ratio (H/M) and washout rate (WO). SPECT imaging assessed [123I]MIBG uptake in 17 left ventricular segments to calculate the summed difference score (SDS). Results: During a median of 4-year follow-up, 22% of patients experienced appropriate ICD interventions, and 25% of patients died or underwent heart transplantation. The mean values of analyzed parameters did not significantly differ between groups. In the univariate analysis, younger age and moderately impaired left ventricular ejection fraction (LVEF) were correlated with more frequent ICD interventions. In comparison, older age and elevated NT-proBNP levels were associated with death or heart transplantation. Additionally, the univariate analysis identified SDS-15' as a prognostic factor for death/heart transplant. The multivariate analysis identified predictors for ICD interventions, including younger age, an EF of 30% or greater, and a larger left ventricular end-diastolic diameter. In contrast, older age and an LVEF of less than 25% were significant predictors of death or heart transplantation. Conclusions: Scintigraphic parameters did not effectively predict ICD interventions or death/heart transplantation, though the summed difference score demonstrated potential as a prognostic factor. Younger age with moderately impaired EF correlated with frequent ICD interventions, while in older age, EF < 25% predicted death or transplantation. Further investigation is needed for patients with borderline EF values.

Association between sebum secretion and cardiac sympathetic dysfunction in Parkinson's disease

BackgroundPatients with Parkinson's disease (PD) have α-synuclein (α-Syn) deposition in the skin, and decreased sebum secretion due to epidermal dysfunction. However, the relationship between sebum secretion and autonomic neuropathies is unknown. MethodsUsing the medical records in our facility, we identified patients newly diagnosed with PD on admission from August 2020 to December 2023. We analyzed whether sebum secretory ability at multiple sites was associated with cardiac sympathetic nerve function that was assessed by cardiac 123I-metaiodobenzylguanidine scintigraphy. ResultsForty patients were included. Their sebum secretion ability positively correlated with the ratio of the average pixel count in the heart to that in the mediastinum (H/M ratio) in the posterior neck, the anterior chest, the arms, and the abdomen. In the multiple regression analysis, those in the arms (β, 8.8; 95 % CI, 4.4–13.2; P < 0.001) and abdomen (β, 1.3; 95 % CI, 0.1–2.5; P = 0.032) were associated with the H/M ratio after controlling for age, sex, and UPDRS part III. ConclusionThis study revealed an association between sebum secretion in the arms and the abdomen, and cardiac sympathetic nerve function in PD patients. The site of the sebum secretory disturbance associated with cardiac sympathetic nerves closely resembled the gradient of α-Syn deposition in the skin, corroborating its deposition pattern. Our findings suggest that noninvasive sebum measurement may serve as an adjunctive diagnostic tool of α-Syn deposition in the skin for PD and provide insights into sympathetic nerve damage alongside cardiac sympathetic nerve assessments.

α-synuclein seed amplification assay sensitivity may be associated with cardiac MIBG abnormality among patients with Lewy body disease.

Although α-synuclein seed amplification assays (α-syn SAA) are promising, its sensitivity may be affected by heterogeneity among patients with Lewy body disease (LBD). We evaluated whether α-syn SAA sensitivity is affected by patient heterogeneity, using 123I-meta-iodobenzylguanidine (MIBG) cardiac scintigraphy in early drug-naïve patients. Thirty-four patients with clinically established or probable Parkinson's disease (PD) and seven with dementia with Lewy bodies (DLB) or prodromal DLB were included. While 85.2% of patients with abnormal cardiac MIBG were α-syn SAA positive, only 14.3% were positive among those with normal scans. Logistic regression analysis showed that MIBG positivity was the only significant variable associated with α-syn SAA positivity (odds ratio 74.2 [95% confidence interval 6.1-909]). Although α-syn SAA is sensitive for LBD in patients with abnormal MIBG, the sensitivity may be lower in those with normal MIBG. Further studies are necessary to evaluate the association between patient heterogeneity and α-syn SAA sensitivity.

International prevalence of transthyretin amyloid cardiomyopathy in high-risk patients with heart failure and preserved or mildly reduced ejection fraction

Background Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underdiagnosed cause of heart failure (HF). Methods This epidemiology study assessed the international prevalence of ATTR-CM among patients aged ≥60 years with a history of HF, left ventricular ejection fraction (LVEF) >40%, an end-diastolic interventricular septum thickness (IVST) ≥12 mm, but without diagnosed amyloidosis, history of LVEF ≤40%, cardiomyopathy of known cause, severe valvular, or coronary heart disease. ATTR-CM was determined using cardiac scintigraphy alongside exclusionary testing for light chain amyloidosis. The study was terminated early due to slow recruitment, without safety concerns. Results Overall, 56/315 (18%; 95% CI: 13.7–22.5) patients with evaluable scintigraphy had ATTR-CM, with a numerically higher prevalence in: Europe (24%) vs. other regions (9% Asia; 5% North America); at specialist vs non-specialist centres (26% vs. 11%); in males vs. females (24% vs. 10%); and in older vs. younger patients (e.g. >40% among those ≥85 years). Other risk markers (p<.05) included a history of carpal tunnel syndrome, higher N-terminal pro B-type natriuretic peptide concentration, and higher end-diastolic IVST. Conclusions ATTR-CM was diagnosed in 18% (95% CI: 13.7–22.5) of evaluable patients with HF, LVEF >40%, and risk markers for ATTR-CM, but no previous diagnosis of amyloidosis. Recruitment bias may have contributed to regional variability. NCT04424914

P092 THE EFFECT OF HYPERTENSION ON THE UTILITY OF ECHOCARDIOGRAM AS AS SUBSTITUTE OF CARDIAC SCNINTIGRAPHY TO DETECT CARDIAC ISCHEMIA

Background and Objective: The cardiac scintigraphy is worthwhile to detect ischemia instead of cardiac catheterization, whereas the echocardiogram is useful to detect movement of myocardium and valves but not to detect ischemia. It is beneficial to predict ischemia by echocardiogram because the disadvantage of cardiac scintigraphy is to be expensive and to expose radiation. The objective of the current study is to evaluate whether the echocardiogram is substituted for the cardiac scintigraphy in the patients with ischemic heart disease and to assess the effect of hypertension on the correlation of two examinations. Methods: We recruited 101 patients with ischemic heart disease who were admitted to Chidoribashi General Hospital and underwent both echocardiogram and cardiac scintigraphy from April 2021 to March 2023. They were divided to two groups by the presence and absence of hypertension at admission. The various parameters of echocardiogram and cardiac scintigraphy were collected retrospectively. The correlation was statistically tested using JMP Pro 17. This study was approved by our ethical committee. Results: In the risk factors of poor prognosis, left ventricular end-systolic volume, summed stress score and ejection fraction (EF) from cardiac scintigraphy were correlated with left ventricular internal dimension (LVD) on echocardiogram. In contrast, summed difference score was correlated with LVD in systole and EF on echocardiogram in the patients without hypertension but not in the patients with hypertension. Conclusions: These results suggest that LVD of echocardiogram may become an indicator to detect cardiac ischemia instead of cardiac scintigraphy.

P094 HYPERTENSION AT ADMISSION AFFECTS THE RESULTS OF CARDIAC SCINTIGRAPHY IN THE ELDER PATIENTS WITH ISCHEMIC HEART DISEASE

Background and Objective: The heart disease is the second most common cause of death after cancer in Japan. Since a myocardial ischemia leads directly to life prognosis, the evaluation of severity of myocardial ischemia is very important to reduce mortality in the patients with ischemic heart disease. The cardiac scintigraphy is less-invasive method to check it than cardiac catheter while results of cardiac scintigraphy are affected by aging and hypertension. The aim of this study is to evaluate the effect of both aging and hypertension at admission on the results of cardiac scintigraphy in the patients with ischemic heart disease. Methods: We recruited 102 patients with ischemic heart disease who were admitted to Chidoribashi General Hospital and underwent cardiac scintigraphy from April 2021 to March 2023. The various parameters such as patient's profile and results of cardiac scintigraphy were collected from electric medical records retrospectively. The comparison was statistically tested using JMP Pro 17. This study was approved by our ethical committee. Results: Thirty-one patients were under 70 years old and seventy-one patients were 70 years old or more. In elder patients, left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV) and the difference of LVEDV from LVESV at rest were more in the patients with hypertension at admission than in the patients without that. In contrast, no difference existed in younger patients. Conclusions: These results suggest that aging may change the ischemic status affected by hypertension.

Associations of cerebrospinal fluid monoamine metabolites with striatal dopamine transporter binding and 123I-meta-iodobenzylguanidine cardiac scintigraphy in Parkinson's disease: Multivariate analyses

Cerebrospinal fluid (CSF) homovanillic acid (HVA) and 5-hydroxyindole acetic acid (5-HIAA), dopamine and serotonin metabolites, are decreased in Parkinson's disease (PD). Although some reported associations between HVA and striatal dopamine transporter (DAT) or 5-HIAA and cardiac 123I-meta-iodobenzylguanidine (MIBG) findings, respectively, whether these are direct associations remained unknown. We retrospectively reviewed 57 drug-naïve patients with PD who underwent CSF analyses and DAT and cardiac MIBG imaging. Z-score of striatal DAT specific binding ratio (Z-SBR) was measured, and the positivity of MIBG abnormalities were judged by an expert. The mean age was 75.5 ± 8.7 years. Thirty-three were MIBG-positive and 24 were MIBG-negative. 5-HIAA levels were significantly lower in the MIBG-positive group. Logistic regression analysis showed that MIBG positivity was associated with 5-HIAA level (odds ratio = 0.751, p = 0.006) but not with age, sex, and HVA. DAT Z-SBR correlated with both HVA and 5-HIAA. Multiple regression analysis showed that HVA was the only significant variable associated with Z-SBR (t = 3.510, p < 0.001). We confirmed direct associations between 5-HIAA and cardiac MIBG, and between HVA and striatal DAT binding.

Serum phosphorus levels associated with nigrostriatal dopaminergic deficits in drug-naïve Parkinson's disease

IntroductionA major component of Lewy bodies is phosphorylated α-synuclein. This post-translational modification of α-synuclein, phosphorylation, may consume a great amount of serum phosphorus. We aimed to investigate serum phosphorus levels and their associations with clinical phenotype and the degeneration of cardiac sympathetic and nigrostriatal dopaminergic neurons in patients with Parkinson's disease (PD). Materials and methodsWe examined serum phosphorus levels in 127 participants (drug-naïve PD, 97; age- and sex-matched controls, 30). Associations of serum phosphorus levels with clinical features, heart-to-mediastinum (H/M) ratio on cardiac 123I-metaiodobenzylguanidine scintigraphy and striatal specific binding ratio of 123I-2-carbomethoxy-3-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (123I-FP-CIT) were examined. ResultsSerum phosphorus levels were 3.4 ± 0.5 mg/dL in patients with PD and were not different from those in controls after controlling for age and sex (p = 0.850). Serum phosphorus levels were significantly lower in patients with PD and decreased H/M ratio than in those with PD and normal H/M ratio (3.3 ± 0.4 mg/dL vs. 3.6 ± 0.5 mg/dL, p = 0.003). Lower serum phosphorus levels were significantly associated with more severe degeneration of nigrostriatal dopaminergic neurons in patients with PD and decreased H/M ratio. However, this association was not observed in patients with PD and normal H/M ratio. ConclusionsSerum phosphorus levels and their association with nigrostriatal dopaminergic degeneration are different between patients with decreased H/M ratio and those with normal H/M ratio. Serum phosphorus levels may reflect the degree of nigrostriatal dopaminergic degeneration in patients with decreased H/M ratio, namely, Body-First PD.

Nuclear imaging techniques for cardiac amyloidosis.

Cardiac amyloidosis is a condition marked by the misfolding of precursor proteins into insoluble amyloid fibrils, leading to restrictive cardiomyopathy and heart failure symptoms. This review discusses advancements in nuclear imaging techniques that enhance the diagnosis and guide the management of cardiac amyloidosis, addressing the critical need for early and accurate detection in clinical practice. Recent studies and guidelines emphasizes the pivotal role of nuclear imaging techniques in diagnosing cardiac amyloidosis. Cardiac scintigraphy, using bone-avid tracers like 99mTc-PYP, 99mTc-DPD, and 99mTc-HMDP, is instrumental in distinguishing between transthyretin amyloidosis and light chain amyloidosis. PET, with tracers such as 11C-Pittsburgh Compound B (11C-PiB) and 18F-Florbetapir, offers significant potential in measuring amyloid burden and monitoring disease progression, providing detailed insights into the myocardial involvement. The advancements in nuclear imaging techniques significantly impact the management of cardiac amyloidosis. These methods allow for a more accurate diagnosis, detailed assessment of disease extent, and better differentiation between amyloidosis types, which are crucial for tailoring treatment approaches. The integration of these techniques into clinical practice is essential for improving patient outcomes and advancing research in cardiac amyloidosis.

Transthyretin cardiac amyloidosis by Cardiac Scintigraphy with 99mTc-diphosphonates and cardiovascular magnetic resonance imaging

Transthyretin cardiac amyloidosis by Cardiac Scintigraphy with 99mTc-diphosphonates and cardiovascular magnetic resonance imaging

A predictive model of super response to cardiac resynchronization therapy in short-term period.

The left bundle branch block, nonischemic heart failure (HF) and female gender are the most powerful predictors of a super response to cardiac resynchronization therapy (CRT). It is important to identify super responders who can derive most benefits from CRT. We aimed to establish a predicting model that could be used for prognosis of a super response to CRT in short-term period. Patients with QRS ≥ 130ms, New York Heart Association (NYHA) II-III class of HF, left ventricle ejection fraction (LVEF) ≤ 35% and indications for CRT were included in the study. Before and 6month after CRT the electrocardiography, echocardiography and cardiac scintigraphy were performed. The study's primary endpoint was the NYHA class improvement ≥ 1 and left ventricle end systolic volume decrease > 30% or LVEF improvement > 15% after 6month CRT. Based on collected data, we developed a predictive model regarding a super response to CRT. Of 49 (100.0%) patients, 32 (65.3%) had a super response to CRT. Patients with a super response were likelier to have a lower cardiac index (p = 0.007), higher rates of interventricular delay (IVD) (p = 0.003), phase standard deviation of left ventricle anterior wall (PSD LVAW) (p = 0.009) and ∆QRS (p = 0.02). Only IVD and PSD LVAW were independently associated with a super response to CRT in univariate and multivariate logistic regression. We created a logistic equation and calculated a cut-off value. The resulting ROC curve revealed a discriminative ability with AUC of 0.812 (sensitivity 90.62%; specificity 70.59%). Our predictive model is able to distinguish patients with a super response to CRT.

Decreased heart rate variability in sympathetic dominant states in Parkinson's disease and isolated REM sleep behavior disorder

IntroductionParkinson's disease (PD) presents with decreased heart rate variability (HRV) from its early stages. However, most of its evidence originates from HRV measurements in parasympathetic dominant states. In this study, we aimed to examine whether HRV in sympathetic dominant states during the head-up tilt table test (HUT) serves as a marker of autonomic dysfunction in PD and isolated REM sleep behavior disorder (iRBD). MethodsWe retrospectively assessed 102 patients with PD, 10 patients with iRBD, and 43 healthy controls. We then measured the coefficient of variation of RR intervals as an HRV parameter in sympathetic dominant states (CVRR-S) and parasympathetic dominant states (CVRR-P). Furthermore, we evaluated parameters of cardiac autonomic function, including HUT and the heart-to-mediastinum (H/M) ratio of cardiac metaiodobenzylguanidine scintigraphy. ResultsPatients with iRBD and PD at Hoehn and Yahr stage I exhibited a significantly decreased CVRR-S compared to healthy controls (controls vs. iRBD vs. PD; 1.82 ± 0.64 % vs. 1.13 ± 0.41 % vs. 1.15 ± 0.51 %, p < 0.001), although no further deterioration was observed in PD at more severe Hoehn and Yahr stages. CVRR-S showed a significant correlation with the H/M ratio in PD (r = 0.51, p < 0.001). Additionally, receiver operating characteristic (ROC) analysis revealed a larger area under the ROC curve in CVRR-S compared to that in CVRR-P for discriminating PD or iRBD from healthy controls. ConclusionHRV in sympathetic dominant states shows the potential to be a marker of autonomic dysfunction in iRBD and early-stage PD, aiding in early diagnosis and patient stratification.

Reduced cardiac 123I-MIBG uptake is a robust biomarker of Lewy body disease in isolated rapid eye movement sleep behaviour disorder

Abstract Cardiac 123I-MIBG scintigraphy is used to assess the function of postganglionic presynaptic cardiac sympathetic nerve endings. 123I-MIBG cardiac uptake is markedly reduced in patients with isolated rapid eye movement sleep behaviour disorder, similar to Parkinson’s disease and dementia with Lewy bodies. As a result, it can be used as an early biomarker of isolated rapid eye movement sleep behaviour disorder. Most patients with isolated rapid eye movement sleep behaviour disorder develop synucleinopathies: Parkinson’s disease, dementia with Lewy bodies or multiple system atrophy. We aimed to investigate whether cardiac postganglionic denervation is present in patients with isolated rapid eye movement sleep behaviour disorder, as well as its possible usefulness as a marker for Lewy body disease status. This retrospective cohort study examined 306 patients (236 men and 70 women; mean age: 68.2 years; age range: 43–87 years) with polysomnography-confirmed isolated rapid eye movement sleep behaviour disorder who were followed for 1–3 months and underwent 123I-MIBG scintigraphy. We retrospectively analysed data from 306 patients with polysomnography-confirmed isolated rapid eye movement sleep behaviour disorder, and their longitudinal outcomes were documented at two centres. Among isolated rapid eye movement sleep behaviour disorder patients, reduced 123I-MIBG uptake was observed in the early and delayed images in 84.4 and 93.4% of patients, respectively, whereas 88.6% of the patients had a high washout rate. This large Japanese two-cohort study (n = 306) found that 91 patients (29.7%) developed an overt synucleinopathy (51 Parkinson’s disease, 35 dementia with Lewy bodies, 4 multiple system atrophy, and 1 cerebellar ataxia) during a mean follow-up duration of 4.72 ± 3.94 years, with a conversion risk of 14.5% at 3 years, 25.4% at 5 years, 41.4% at 8 years and 52.5% at 10 years. On the other hand, among patients with heart-to-mediastinum ratio &amp;lt; 2.2 in the delayed images (n = 286), 85 (29.7%) developed Parkinson’s disease or dementia with Lewy bodies during a mean follow-up duration of 4.71 ± 3.94 years, with a conversion risk of 14.5% at 3 years, 25.6% at 5 years, 42.0% at 8 years and 51.0% at 10 years. Among the 33 patients who underwent repeat 123I-MIBG scintigraphy, there was a progressive decline in uptake over the next 4.2 years, with patients exhibiting reduced uptake progressing to Parkinson’s disease or dementia with Lewy bodies. In contrast, patients without decreased 123I-MIBG uptake progressed to multiple system atrophy. Reduced cardiac 123I-MIBG uptake was detected in over 90% of isolated rapid eye movement sleep behaviour disorder patients, with progression to Parkinson’s disease or dementia with Lewy bodies, rather than multiple system atrophy, over time. Reduced 123I-MIBG uptake is a robust maker for Lewy body disease among isolated rapid eye movement sleep behaviour disorder patients.

Diagnosis and prognosis of abnormal cardiac scintigraphy uptake suggestive of cardiac amyloidosis using artificial intelligence: a retrospective, international, multicentre, cross-tracer development and validation study

The diagnosis of cardiac amyloidosis can be established non-invasively by scintigraphy using bone-avid tracers, but visual assessment is subjective and can lead to misdiagnosis. We aimed to develop and validate an artificial intelligence (AI) system for standardised and reliable screening of cardiac amyloidosis-suggestive uptake and assess its prognostic value, using a multinational database of 99mTc-scintigraphy data across multiple tracers and scanners. In this retrospective, international, multicentre, cross-tracer development and validation study, 16 241 patients with 19 401 scans were included from nine centres: one hospital in Austria (consecutive recruitment Jan 4, 2010, to Aug 19, 2020), five hospital sites in London, UK (consecutive recruitment Oct 1, 2014, to Sept 29, 2022), two centres in China (selected scans from Jan 1, 2021, to Oct 31, 2022), and one centre in Italy (selected scans from Jan 1, 2011, to May 23, 2023). The dataset included all patients referred to whole-body 99mTc-scintigraphy with an anterior view and all 99mTc-labelled tracers currently used to identify cardiac amyloidosis-suggestive uptake. Exclusion criteria were image acquisition at less than 2 h (99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid, 99mTc-hydroxymethylene diphosphonate, and 99mTc-methylene diphosphonate) or less than 1 h (99mTc-pyrophosphate) after tracer injection and if patients' imaging and clinical data could not be linked. Ground truth annotation was derived from centralised core-lab consensus reading of at least three independent experts (CN, TT-W, and JN). An AI system for detection of cardiac amyloidosis-associated high-grade cardiac tracer uptake was developed using data from one centre (Austria) and independently validated in the remaining centres. A multicase, multireader study and a medical algorithmic audit were conducted to assess clinician performance compared with AI and to evaluate and correct failure modes. The system's prognostic value in predicting mortality was tested in the consecutively recruited cohorts using cox proportional hazards models for each cohort individually and for the combined cohorts. The prevalence of cases positive for cardiac amyloidosis-suggestive uptake was 142 (2%) of 9176 patients in the Austrian, 125 (2%) of 6763 patients in the UK, 63 (62%) of 102 patients in the Chinese, and 103 (52%) of 200 patients in the Italian cohorts. In the Austrian cohort, cross-validation performance showed an area under the curve (AUC) of 1·000 (95% CI 1·000-1·000). Independent validation yielded AUCs of 0·997 (0·993-0·999) for the UK, 0·925 (0·871-0·971) for the Chinese, and 1·000 (0·999-1·000) for the Italian cohorts. In the multicase multireader study, five physicians disagreed in 22 (11%) of 200 cases (Fleiss' kappa 0·89), with a mean AUC of 0·946 (95% CI 0·924-0·967), which was inferior to AI (AUC 0·997 [0·991-1·000], p=0·0040). The medical algorithmic audit demonstrated the system's robustness across demographic factors, tracers, scanners, and centres. The AI's predictions were independently prognostic for overall mortality (adjusted hazard ratio 1·44 [95% CI 1·19-1·74], p<0·0001). AI-based screening of cardiac amyloidosis-suggestive uptake in patients undergoing scintigraphy was reliable, eliminated inter-rater variability, and portended prognostic value, with potential implications for identification, referral, and management pathways. Pfizer.

The role of 123-I-MIBG cardiac scintigraphy in the differential diagnosis between dementia with Lewy bodies and Alzheimer's disease.

Although detailed diagnostic guidelines are available, differentiating dementia with Lewy bodies from Alzheimer's disease is often difficult. 123-I-MIBG cardiac scintigraphy is one of the tools which have been proposed for the diagnostic procedure. The present review is aimed at evaluating the available literature about this topic. Studies assessing the use of this technique to differentiate between the two diseases have been examined and reported. Overall, despite a certain study-to-study variability, the available literature suggests that 123-I-MIBG cardiac scintigraphy is an effective tool in differentiating between the two diseases, with high sensitivity and specificity values. Although the large-scale application of this technique is limited by possible interactions with specific medications and comorbidities, the reported studies are supportive for the usefulness of this technique in clinical practice.

Comparison of Echocardiography and Myocardial Scintigraphy to Detect Cancer Therapy-Related Cardiovascular Toxicity in Breast Cancer Patients.

The mortality rate of cancer patients has been decreasing; however, patients often suffer from cardiac disorders due to chemotherapy or other cancer therapies (e.g., cancer-therapy-related cardiovascular toxicity (CVR-CVT)). Therefore, the field of cardio-oncology has drawn more attention in recent years. The first European Society of Cardiology (ESC) guidelines on cardio-oncology was established last year. Echocardiography is the gold standard for the diagnosis of CVR-CVT, but many breast cancer patients are unable to undergo echocardiography due to their surgery wounds or anatomical reasons. We performed a study to evaluate the usefulness of myocardial scintigraphy using Iodine-123 β-methyl-P-iodophenyl-pentadecanoic acid (123I-BMIPP) in comparison with echocardiography and published the results in the Journal of Imaging last year. This is the secondary analysis following our previous study. A total of 114 breast cancer patients who received chemotherapy within 3 years underwent echocardiography, as well as Thallium (201Tl) and 123I-BMIPP myocardial perfusion and metabolism scintigraphy. The ratio of isotope uptake reduction was scored by Heart Risk View-S software (Nihon Medi-Physics). The scores were then compared with the echocardiography parameters. All the patients' charts and data from January 2022 to November 2023 were reviewed for the secondary analysis. Echocardiogram parameters were obtained from 99 patients (87% of total patients). No correlations were found between the echocardiography parameters and Heart Risk View-S scores of 201Tl myocardial perfusion scintigraphy, nor those of the BMIPP myocardial metabolism scintigraphy. In total, 8 patients out of 114 (7.0%) died within 22 months, while 3 patients out of 26 CVR-CVT patients (11.5%) died within 22 months. Evaluation by echocardiography was sometimes difficult to perform on breast cancer patients. However, other imaging modalities, including myocardial scintigraphy, cannot serve as alternatives to echocardiography. Cardiac scintigraphy detects circulation disorder or metabolism disorder in the myocardium; therefore, it should be able to reveal myocardial damage to some extent. The mortality rate of breast cancer patients was higher with CVR-CVT. A new modality to detect CVR-CVT besides echocardiography can possibly be anticipated for patients who cannot undergo echocardiography.

Appraisal of amyloidosis imaging practices in the Middle East/North Africa (PYP-MENA).

Whereas recommendations to optimize performance and yield of cardiac scintigraphy studies with bone-seeking tracers have been published, little is known about real-world adherence to these best practices, especially outside North America and Europe. Accordingly, we described imaging practices with this modality in a sample of nuclear laboratories in the Middle East/North Africa (MENA) region. Laboratories performing radionuclide imaging for cardiac amyloidosis in the MENA region were invited to participate in this study to describe installed camera systems, type and dose of bone-avid tracers used, imaging protocols, and criteria used for study interpretation. Out of 19 invited sites, 10 completed the survey (70% government-run; 90% accredited), sites have been involved with amyloid imaging for a median of 49 months (interquartile range 24-60). The median injected dose was 20 mCi (range 10-25), and PYP was used by 90% of sites in this sample. Planar imaging with single photon emission computed tomography (SPECT) reconstruction was performed at all sites, including seven sites that performed SPECT/CT reconstruction. Lastly, only 50% of sites relied on evidence of myocardial uptake by SPECT to confirm the diagnosis of ATTR cardiomyopathy, while the rest relied on visual assessment and heart/contralateral ratio. This study is the first to describe variation in imaging practices across sites in the MENA region, especially in acquisition protocols and interpretation standards. Eliminating heterogeneities identified by this study will harmonize image interpretation and reporting and will facilitate successful conduct of regional multi-centre studies.

Diagnosis and treatment of hereditary transthyretin amyloidosis with polyneuropathy in the United States: Recommendations from a panel of experts.

Hereditary transthyretin (ATTRv; v for variant) amyloidosis is a rare, multisystem, progressive, and fatal disease in which polyneuropathy is a cardinal manifestation. Due to a lack of United States (US)-specific guidance on ATTRv amyloidosis with polyneuropathy, a panel of US-based expert clinicians convened to address identification, monitoring, and treatment of this disease. ATTRv amyloidosis with polyneuropathy should be suspected in unexplained progressive neuropathy, especially if associated with systemic symptoms or family history. The diagnosis is confirmed through genetic testing, biopsy, or cardiac technetium-based scintigraphy. Treatment should be initiated as soon as possible after diagnosis, with gene-silencing therapeutics recommended as a first-line option. Consensus is lacking on what represents "disease progression" during treatment; however, the aggressive natural history of this disease should be considered when evaluating the effectiveness of any therapy.