Risultati per: L'imaging nella urolitiasi

Introduction
Attributing musculoskeletal (MSK) pain to normal and commonly occurring imaging findings, such as tendon, cartilage and spinal disc degeneration, has been shown to increase people’s fear of movement, reduce their optimism about recovery and increase healthcare costs. Interventions seeking to reduce the negative effects of MSK imaging reporting have had little effect. To understand the ineffectiveness of these interventions, this study seeks to scope their behavioural targets, intended mechanisms of action and theoretical underpinnings. This information alongside known barriers to helpful reporting can enable researchers to refine or create new more targeted interventions.

Methods and analysis
The scoping review will be conducted in accordance with the JBI methodology for scoping reviews and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. Search terms will be devised by the research team. Searches of MEDLINE, EMBASE, CINAHL, AMED and PsycINFO from inception to current day will be performed. The review will include studies, which have developed or evaluated interventions targeting the reporting of MSK imaging. Studies targeting the diagnosis of serious causes of MSK pain will be excluded. Two independent authors will extract study participant data using predefined extraction templates and intervention details using the Template for Intervention Description and Replication checklist. Interventions will be coded and mapped to the technique, mechanism of action and behavioural target according to the Capability, Opportunity, Motivation-Behaviour (COM-B) model categories. Any explicit models or theories used to inform the selection of interventions will be extracted and coded. The study characteristics, behaviour change techniques identified, behavioural targets according to the COM-B and context specific theories within the studies will be presented in narrative and table form.

Ethics and dissemination
The information from this review will be used to inform an intervention design process seeking to improve the communication of imaging results. The results will also be disseminated through a peer-reviewed publication, conference presentations and stakeholder events.

Stroke, Volume 54, Issue 12, Page 3081-3089, December 1, 2023. BACKGROUND:The indication for mechanical thrombectomy (MT) in stroke patients with large vessel occlusion has been constantly expanded over the past years. Despite remarkable treatment effects at the group level in clinical trials, many patients remain severely disabled even after successful recanalization. A better understanding of this outcome variability will help to improve clinical decision-making on MT in the acute stage. Here, we test whether current outcome models can be refined by integrating information on the preservation of the corticospinal tract as a functionally crucial white matter tract derived from acute perfusion imaging.METHODS:We retrospectively analyzed 162 patients with stroke and large vessel occlusion of the anterior circulation who were admitted to the University Medical Center Lübeck between 2014 and 2020 and underwent MT. The ischemic core was defined as fully automatized based on the acute computed tomography perfusion with cerebral blood volume data using outlier detection and clustering algorithms. Normative whole-brain structural connectivity data were used to infer whether the corticospinal tract was affected by the ischemic core or preserved. Ordinal logistic regression models were used to correlate this information with the modified Rankin Scale after 90 days.RESULTS:The preservation of the corticospinal tract was associated with a reduced risk of a worse functional outcome in large vessel occlusion–stroke patients undergoing MT, with an odds ratio of 0.28 (95% CI, 0.15–0.53). This association was still significant after adjusting for multiple confounding covariables, such as age, lesion load, initial symptom severity, sex, stroke side, and recanalization status.CONCLUSIONS:A preinterventional computed tomography perfusion–based surrogate of corticospinal tract preservation or disconnectivity is strongly associated with functional outcomes after MT. If validated in independent samples this concept could serve as a novel tool to improve current outcome models to better understand intersubject variability after MT in large vessel occlusion stroke.

Circulation, Ahead of Print. Background:Hypertensive pregnancy disorders are associated with adverse cardiac remodeling, which can fail to reverse postpartum in some women. The Physician Optimized Postpartum Hypertension Treatment trial demonstrated improved blood pressure control, while the cardiovascular system recovers postpartum, associates with persistently reduced blood pressure. We now report the impact on cardiac remodeling.Methods:In this prospective, randomized, open-label, blinded endpoint trial, in a single UK hospital, 220 women were randomly assigned 1:1 to self-monitoring with research physician-optimized antihypertensive titration, or usual postnatal care from primary care physician and midwife. Participants were aged 18 years or over, with pre-eclampsia or gestational hypertension, requiring antihypertensives on hospital discharge postnatally. Pre-specified secondary cardiac imaging outcomes were recorded by echocardiography around delivery, and again at blood pressure primary outcome assessment, around nine months postpartum, when cardiovascular magnetic resonance was also performed.Results:187 women (101 intervention; 86 usual care) underwent echocardiography at baseline and follow up, at a mean 258+/-14.6 days postpartum, of which 174 (93 intervention; 81 usual care) also had cardiovascular magnetic resonance at follow up. Relative wall thickness by echocardiography was 0.06 (95% CI0.07 to 0.05, P=

Circulation, Volume 148, Issue Suppl_1, Page A12595-A12595, November 6, 2023. Introduction:Conventional Cardiac implantable electronic devices (CIEDs) implantation requires fluoroscopy. Risks involved with implantation include pneumothorax, lead dislodgement, and perforation of the right ventricular wall. In addition, there are long-term risks of malignancy associated with prolonged and repeated use of radiation over the decades of operators’ employment and mechanical injuries related to heavy personal protection equipment. To reduce these risks, we aimed to study the utilization and safety of ultrasound (US) for the entire procedure to implant single-chamber devices.Methods:The RADICAI USE study (Reduction or Elimination of Radiation Use in Single Chamber Cardiac Devices using ultrasound) is a prospective, single-arm and multi-operator case series enrolled patients awaiting a single-chamber CIED. A fluoroscopic cut-off time of 20 seconds was used to define the success (Group A) or failure (Group B) of using the US for the entire implant duration. Patients were followed up at 1 week, 1 month and 1-year post-implant.Results:The study enrolled 63 patients, with 50 pacemakers and 13 ICDs, a mean age of 79.5 ± 13.8 years (95% CI = 76.1 – 82.9), and a mean weight of 74.1 ± 14.6 (95% CI = 70.5 – 77.7). Overall, 53 (84.1%) CIEDs were successfully implanted with a radiation time of less than 20 seconds (Group A). Fluoroscopic over 20 seconds was required due to poor echocardiographic windows, challenging access, or anatomy. No iatrogenic new or worsening of tricuspid regurgitation was noted. The mean procedure time including US setup time was 65.2 ± 20.2 (95% CI = 60.2 -70.2) minutes. Fluoroscopic time was significantly reduced in Group A compared to Group B (5.8 ± 4.5s vs 109.5 ± 92.9s, p = 0.004). Follow-up showed no device-related complications, with only two patients requiring lead revisions due to poor sensitivity, one unrelated to US use and another probably related.Conclusions:US-guided implantation of single-chamber CIEDs is feasible and safe, reducing the need for fluoroscopic guided implantation and subsequent risks of higher radiation exposure. Further studies are required to evaluate the cost-effectiveness and to explore fluoroscopic-free single-chamber CIED implantations using the US.

Circulation, Volume 148, Issue Suppl_1, Page A16082-A16082, November 6, 2023. Introduction:Noninvasive cardiac stress testing is valuable for early diagnosis and optimizing management of patients with coronary artery disease (CAD). Historically, Black patients have experienced both underdiagnosis and undertreatment of CAD. We evaluated racial disparities in patients undergoing nuclear myocardial perfusion imaging (MPI). Different modalities (MPI (SPECT, PET) vs. stress echocardiography) have variations in accuracy, cost and radiation exposure, which may reflect provider biases.Methods:Patient-reported demographics, clinician-reported cardiac risk factors and MPI study characteristics from a large Connecticut health system (2016 – 2022) were compared for Black and White patients in both general and matched cohorts (1:1 matched for demographics and risk factors).Results:The study included 123,069 cardiac stress tests from 10.5% Black and 76.2% White patients (largely similar to overall Connecticut population: 12.7% Black, 78.8% White). Black patients were younger (56.7±13.3 vs. 62.1±13.4 years, p< 0.001), more likely female (58.7 vs. 44.7%, p

Circulation, Volume 148, Issue Suppl_1, Page A13918-A13918, November 6, 2023. Introduction:PAH is a deadly disease without cure. Formalized risk stratification allows therapeutic adjustments that optimize drug utilization. Risk scores, like REVEAL 2.0 recommended by PAH guidelines only offer good discrimination. Our goal was to create risk models with excellent discrimination (C-Index over 0.8), using modern statistical techniques and expanded variable pools including imaging and genomics. The AIM of this study was to demonstrate the improved performance with the addition of cardiac MRI variables.Methods:PAH patients from the ASPIRE cardiac MRI database were analyzed. Imaging variable (IMV) selection was performed using three machine learning methods: logistic regression, Lasso, and Random Forest. Rankings of the IMVs from these sources were aggregated to arrive at a consensus list. The selected IMVs were added to the set of variables for deriving the REVEAL 2.0 composite score. Bayesian networks (BN) were then built to predict 1-year survival based on the Tree-Augmented naïve Bayes (TAN) algorithm. Five-fold cross-validation was performed to assess the improvement in survival prediction from adding the selected imaging variables.Results:A total of 343 PAH previously diagnosed subjects were included in this analysis. The rank aggregation algorithm identified several IMV, including LVSVI, RVCO, LVEDVI, and RVESVI, that were predictive of survival but not the REVEAL 2.0 composite score. Adding these IMV to the REVEAL 2.0 variables, we built a BN model that depicts the non-linear relationships among the predictors and one-year survival (Fig 1). We obtained an average AUC of 0.83 over the five cross-validation test sets, an improvement over the AUC of 0.78 using only the REVEAL 2.0 variables. A Mann-Whitney non-parametric test shows the improvement is statistically significant at the 0.1 level.Conclusion:Advanced statistical models that include cardiac IMVs improve performance of PAH risk assessment models.

Circulation, Volume 148, Issue Suppl_1, Page A13954-A13954, November 6, 2023. Introduction:Patients with a diagnosis of transient ischemic attack (TIA) or minor stroke with an acute infarction on brain imaging are at higher risk of subsequent stroke. Our goal was to establish if the Canadian TIA Score (CTS) could predict infarction on magnetic resonance imaging (MRI) when a computed tomography (CT) scan was negative for stroke and aimed to identify clinical factors predictive of a positive MRI.Methods:Patients were selected from the prospective cohort used for the validation of the CTS in 13 centers. Patients with negative CT scans who underwent MRI within 7 days were analyzed. The main outcome was cerebral infarction defined as MRI diffusion-weighted imaging (DWI) positivity. Associations between confirmed stroke and demographic characteristics, clinical features, laboratory findings, and medications were determined using a multivariate logistic regression model. Subsequent stroke rate at 7, 30, and 90 days was analyzed.Results:From 11,507 patients, 1,048 met inclusion criteria. MRI positivity was 15.4%, 30.4%, and 50.0% for the low, medium, and high-risk CTS groups, respectively. Subsequent stroke/TIA rates were higher with confirmed ischemic lesions on MRI at 90 days: twice (10.0%) in the low-risk group, 51 (22.3%) in the medium-risk group, and 20 (24.7%) in high-risk patients. 1.7% of DWI negative patients had a subsequent stroke. Predictive factors in multivariable models for DWI positivity in the medium-risk group were male (OR=1.53; 95% CI 1.11-2.12), hypertension (OR=1.63; 95% CI 1.17-2.27), clinical history of unilateral weakness (OR=2.09; 95% CI 1.50-2.91), language disturbance (OR=1.43; 95% CI 1.03-1.97), and the presence of pronator drift on examination (OR=2.18; 95% CI 1.37-3.47).Conclusion:The CTS helps predict MRI findings and confirmed ischemic lesion is a predictor of the recurrence risk of stroke. The low-risk group showed few positive MRIs and had a lower recurrence rate justifying less urgent MRI. In the medium-risk group, we highlighted findings that should raise the suspicion of an ischemic lesion and these patients should be prioritize for rapid investigation of stroke etiology. In the high-risk group, patients are at risk for stroke despite negative imaging and MRI should not delay management.

Circulation, Volume 148, Issue Suppl_1, Page A17817-A17817, November 6, 2023. Introduction:Our previous work led to developing a deep learning algorithm for retinal images, Reti-CVD, which effectively predicted cardiovascular disease (CVD) events in individuals without CVD history, leveraging coronary artery calcium (CAC) scores for algorithm training.Hypothesis:This study aims to assess the capability of deep learning-assisted retinal imaging to predict CVD events among prediabetic and diabetic patients using the data from the UK Biobank.Methods:Our study included prediabetic and diabetic patients from the UK Biobank. Reti-CVD scores were calculated and categorized into three risk groups – low (n=550), moderate (n=276), and high (n=275), based on the 50th and 75th percentiles, following a 2:1:1 ratio. To assess the Reti-CVD’s ability in predicting fatal and non-fatal CVD events, we performed a survival analysis on the longitudinal data from the UK Biobank using Cox proportional-hazards models and hazard ratios (HRs).Results:Among the 1101 prediabetic or diabetic patients at the onset, 138 (12.5%) experienced CVD events. According to Reti-CVD scores, these events were found as 8.2% (45/550), 15.2% (42/276), and 18.5% (51/275) in the low, moderate, and high-risk groups over a median follow-up period of 11 years, respectively. After adjusting for factors such as age, gender, hypertensive medication use, statin use, and smoking history, a significant association was observed between the Reti-CVD and the incidence of CVD events (HR=1.57, 95% CI, 1.00-2.47 for the moderate-risk group; HR=1.88, 95% CI, 1.19-2.98 for the high-risk group compared to the low-risk group). An increasing HR trend of 1.36 (95% CI, 1.09-1.70) was observed across risk groups in the prediction of CVD events.Conclusions:The Reti-CVD offers a valuable tool for risk stratification among prediabetic and diabetic patients, indicating its potential in managing these high-risk groups.

Circulation, Volume 148, Issue Suppl_1, Page A18850-A18850, November 6, 2023. Background:Intravascular imaging (IVI) namely intravascular ultrasound (IVUS) and optical coherence tomography (OCT), presents as a promising imaging modality for drug-eluting stent (DES) implantation compared to the gold-standard conventional two-dimensional angiography. IVI provides detailed information on vessel lumen, lesion length, and degree of calcification. For this purpose, we conducted a meta-analysis by pooling recently conducted randomized control trials (RCTs) to compare IVI with angiography for DES implantation.Hypothesis:IVI is associated with a significant reduction in CV events for DES implantation.Methods:Fourteen RCTs reporting CV outcomes with IVI versus angiography-guided stent implantation in CAD patients undergoing PCI were included in MEDLINE, and Scopus databases (Inception till May 2023). The primary outcome of interest was target-lesion revascularization (TLR). The outcome measures were summary random effects risk ratio (RR) with 95% confidence intervals.Results:A total of 8,946 patients (IVI 4,751 vs. angiography 4,195; mean age 61.7 years) were included. Over a median follow-up of 15 months (12-24.3), IVI was associated with significantly reduced TLR (RR 0.63 [0.49, 0.79]; Figure 1), target vessel revascularization (RR 0.66 [0.53, 0.83]), and major adverse cardiovascular events (MACE) (RR 0.69 [0.58, 0.78]) vs. conventional angiography for PCI. However, no significant difference was observed in all-cause mortality between the two imaging modalities (RR 0.85 [0.63, 1.15]). Meta-regression analysis showed no significant impact of follow-up duration, baseline comorbidities such as hypertension, smoking status, previous myocardial infarction, and stent length on TLR incidence.Conclusion:IVI was associated with improved CV outcomes in terms of reduced TLR, TVR, and MACE incidence when compared with traditional angiography in CAD patients for stent implantation.

Circulation, Volume 148, Issue Suppl_1, Page A16201-A16201, November 6, 2023. Introduction:Several predictive heart failure (HF) models exist to determine incident HF. We aimed to create a model that uses cardiac CT imaging biomarkers to improve discrimination scores of incident HF.Hypothesis:Cardiac CT variables increase predictive abilities of the Pooled Cohort Equations to Prevent HF (PCP-HF) score (a validated 10-year risk of new-onset HF prediction model) in all HF, HFrEF, and HFpEF.Methods:MESA participants aged 45-84 years old and free of clinical CVD who completed a cardiac CT were included for study analysis. The outcome of interest was new-onset HF. Clinical risk factors were obtained. Cardiac CT variables analyzed included left ventricular size index (LVSi) and calcifications of coronary arteries (CAC), aortic valve (AVC), mitral valve (MVC), and thoracic aorta (TAC).Results:Among 6,667 MESA study participants who underwent cardiac CT, 426 events of new-onset HF occurred during the follow-up period. Among the 426 events, 173 (40.6%) were categorized as HFrEF, 193 (45.3%) were categorized as HFpEF, and 60 (14.1%) had missing ejection fraction data. The reported data is based on the Cox model adjusted for all CT variables in one model with log(PCP-HF). For all incident HF (preserved and reduced), CAC (HR 1.10 95% CI 1.05-1.15, p

Circulation, Volume 148, Issue Suppl_1, Page A15082-A15082, November 6, 2023. Introduction:Right ventricular function and ventricular dynamics associate with outcomes in pulmonary hypertension (PH). Measures of RV strain describe ventricular mechanics but are not included in RV function assessments. This study aimed to develop novel RV imaging-hemodynamic phenotypes using unsupervised machine learning.Methods:Participants with cardiac magnetic resonance (CMR) and right heart catheterization data were identified from The Ohio State University CMR PH registry (n=81). RV areas were segmented from CMR 4-chamber images and used to determine RV free wall (RVFW) and septal strain. K-medoids clustering was used on imaging features, RV hemodynamics, and RV function (Figure A). Correlation analysis was used to reduce collinearity. Significance was measured with Kruskal Wallis and chi-squared tests. A p-value < 0.05 was considered significant.Results:Participants were assigned to three clusters and top contributors to cluster assignment were RVEF, RVFW strain, and Ea. RV phenotypes progress from mild/no RV dysfunction (Cluster 1) to severe RV dysfunction (Cluster 3) (Figure A). Cluster 1 had normal RV function with high RVEF and PA compliance, preserved LVEF, low RVSP, and low Eed. Compared to cluster 1, cluster 2 demonstrates more RV dysfunction with reduced RVEF, stroke volume, and PA compliance with an increase in RVSP but no change in Eed. In addition to more RV dysfunction (decreased RVEF and stroke volume), cluster 3 had increased RA pressure and Eed. In terms of RV strain, (Figure B), cluster 2 had less negative RVFW and septal strain compared to cluster 1. In cluster 3, RV septal strain is similar to cluster 2 but with decreased RVFW strain.Conclusions:Imaging and hemodynamic RV variables contribute to identification of novel RV-centric phenotypes and should be included in phenotyping efforts to better describe altered ventricular dynamics contributing to RV dysfunction in PH.

Circulation, Volume 148, Issue Suppl_1, Page A16260-A16260, November 6, 2023. Introduction:Late gadolinium enhancement (LGE) in pediatric patients with acute myocarditis has been shown to be a risk factor for adverse events. On follow up cardiac magnetic resonance imaging (CMR), some patients show improvement and/or resolution of LGE but others do not. Factors associated with residual LGE have not been described.Hypothesis:Measurements on initial CMR would be associated with degree of improvement of LGE on follow up CMR.Methods:We conducted a retrospective cohort study of patients

Circulation, Volume 148, Issue Suppl_1, Page A14368-A14368, November 6, 2023. Introduction:We aimed to validate a PET imaging biomarker for the detection of incipient anthracycline-induced cardiotoxicity. This condition affects >5% of all pediatric cancer patients, leading to long-term health deficits. We hypothesized that fibroblast activation protein (FAP) would be a suitable candidate due to its role in extracellular matrix remodeling and fibrosis during early cardiac injury and the availability of high-affinity PET probes.Methods:Cardiotoxicity was established in male C57BL/6J mice by administering a cumulative 24 mg/kg dose of doxorubicin (DOX) intraperitoneally over 2 weeks [1]. The DOX mice were imaged serially with echocardiography and [68Ga]Ga-FAPI-04 PET over 12 weeks and compared to age- and sex-matched controls. Fractional shortening (FS) was determined from the echocardiograms, and cardiac uptake of [68Ga]Ga-FAPI-04 was quantified and expressed as percent injected dose per cubic centimeter (%ID/cm3). Heart tissue samples were collected and used for the analysis of bulk RNA-seq, RT-qPCR, Western blot, in situ hybridization (ISH), and histological staining. Finally, we used the DAVID tools and STRING database to confirm the relationship between PET signal and gene expression.Results:DOX mice exhibited decreased body weight (33% by 9 weeks after end-of-treatment) and heart weight-to-tibia length ratio (HW/TL, 39%). Cardiac [68Ga]Ga-FAPI-04 PET signal was significantly higher (1.7-fold) in DOX mice from 2 weeks through the study endpoint. By contrast, no cardiac dysfunction was evident by echocardiography until 10 weeks after end-of-treatment, at which point FS was significantly reduced relative to the control group (30%). Transcription and translation of FAP were elevated in the DOX hearts, in agreement with the PET data. In the heatmap generated from the RNA-seq data, genes related to cell adhesion and extracellular remodeling were significantly upregulated in the DOX mice relative to controls. The H-score of FAP ISH was linearly related to the cardiac signal of [68Ga]Ga-FAPI-04 PET (p = 0.001).Conclusions:FAP is a suitable imaging biomarker for cardiotoxicity and FAPI-PET is a promising tool for identifying patients at risk of cardiotoxicity during or after anthracycline chemotherapy.

Circulation, Volume 148, Issue Suppl_1, Page A15036-A15036, November 6, 2023. Introduction:Cardiac magnetic resonance(CMR), especially T1 mapping, has an important role in the diagnosis of Fabry disease, but the differential value in myocardial diseases with hypertrophic phenotype needs further study. More importantly, there has been no systematic study of the difference between different CMR techniques indistinguishing Fabry cardiomyopathy from hypertrophic cardiomyopathy (HCM).Hypothesis:Myomapping technology can be a parameter in distinguishing Fabry cardiomyopathy from HCM.Methods:We continuously included patients with clinically diagnosed hypertrophic cardiomyopathy, completed systematic magnetic resonance imaging, and used genetic testing as the diagnostic criteria. We reported the prevalence rate in the population of HCM, and deeply conducted comparative studies on the differences in magnetic resonance characteristics between Fabry disease and HCM. We also analyzed the diagnostic value of magnetic resonance imaging in distinguishing Fabry cardiomyopathy from HCM.Results:We continuously included patients diagnosed with hypertrophic cardiomyopathy at West China Hospital from 2012 to 2022 and completed systematic magnetic resonance imaging examinations. We reported the prevalence of Fabry cardiomyopathy in the population using genetic testing as the diagnostic criteria, and deeply conducted comparative studies on the differences in CMR features between Fabry disease and HCM. We also analyzed the diagnostic value of CMR in distinguishing Fabry cardiomyopathy from HCM.Conclusions:We found a prevalence of 13 (2.6%) cases of Fabry disease in the hypertrophic cardiomyopathy cohort (494 cases). Our further analysis found that there were no significant differences in the degree of hypertrophy, overall cardiac function and size of Fabry patients compared with patients with HCM, as well as strain analysis. NativeT1 was significantly reduced in Fabry disease, and segmental analysis found that the basal and middle ventricular septum and anterior wall were the most obvious. ECV differed significantly between the two groups. There was no difference in T2 between the two groups. ROC analysis showed that T1 had the most discriminating value

Circulation, Volume 148, Issue Suppl_1, Page A13430-A13430, November 6, 2023. Introduction:Precise risk assessment is essential for accurate management of patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR). This study aimed to assess the prognostic implications of cardiovascular magnetic resonance (CMR)-derived imaging biomarkers in a large cohort of AS patients.Methods:145 patients with severe AS underwent CMR imaging before TAVR. Image analyses included myocardial volumes, CMR-feature-tracking derived left and right atrial (LA & RA) as well as left and right ventricular (LV & RV) strain, myocardial T1 mapping as well as late gadolinium enhancement analyses. Cardiovascular (CV) mortality was defined as primary clinical endpoint.Results:Patients with CV death during follow-up had significantly enlarged RV enddiastolic volumes (82.9ml/ml2[70.8-96.0] vs. 62.8ml/ml2[54.7-76.0], p

Circulation, Volume 148, Issue Suppl_1, Page A17405-A17405, November 6, 2023. Introduction:Activation of matrix metalloproteinase (MMPs) post myocardial infarction (MI) predicts post-MI remodeling. MMP activation in the heart can be detected using 99mTc-RP805 a radiolabel peptidomimetic that binds to the catalytic site. The purpose of this study was to evaluate the biodistribution, dosimetry, and specificity of clinical grade 99mTc-RP805 for first-in-human studies.Methods:Male and female rats (n=24) were injected with99mTc-RP805 and euthanized at 1, 3, 7 or 12 hr post injection to determine biodistribution and estimate human dosimetry. Organ activity (%ID/g) was used to estimate whole body and organ effective dose using OLINDA. MI was induced in rats by LAD ligation (n=19) and injected with99mTc-RP805 3 days post MI, and rats were euthanized 3 hr after injection in absence (n=9) or presence (n=10) of a 100 x blocking dose of RP805 (257 ug/kg) 30 min prior to radiotracer injection to establish specificity. In vivo SPECT/CT imaging was performed with GMP grade99mTc-RP805 in rats post-MI (n=4).Results:The %ID/g for each organ is presented per time point (Fig 1 A). The highest radiation dose was found in male kidneys at 3 hr (%ID/g: 6.11 ± 0.54), female kidneys at 1hr (%ID/g: 6.31 ± 0.88). The estimated total body dose for human males was calculated at 0.172 mSv/mCi and 0.283 mSv/mCi for females, equaling a dose of 3.4 mSv and 5.7 mSv for a 30 mCi injection in males and females, respectively. There is 4 fold increase 99mTc-RP805 uptake in the infarct area compared to the normal LV (Fig 1B) and uptake was blocked with cold compound (ANOVA, p