Static CT myocardial perfusion imaging: image quality, artifacts including distribution and diagnostic performance compared to 82Rb PET

Background Rubidium-82 positron emission tomography (82Rb PET) MPI is considered a noninvasive reference standard for the assessment of myocardial perfusion in coronary artery disease (CAD) patients. Our main goal was to compare the diagnostic performance of static rest/ vasodilator stress CT myocardial perfusion imaging (CT-MPI) to stress/ rest 82Rb PET-MPI for the identification of myocardial ischemia. Methods Forty-four patients with suspected or diagnosed CAD underwent both static CT-MPI and 82Rb PET-MPI at rest and during pharmacological stress. The extent and severity of perfusion defects on PET-MPI were assessed to obtain summed stress score, summed rest score, and summed difference score. The extent and severity of perfusion defects on CT-MPI was visually assessed using the same grading scale. CT-MPI was compared with PET-MPI as the gold standard on a per-territory and a per-patient basis. Results On a per-patient basis, there was moderate agreement between CT-MPI and PET-MPI with a weighted 0.49 for detection of stress induced perfusion abnormalities. Using PET-MPI as a reference, static CT-MPI had 89% sensitivity (SS), 58% specificity (SP), 71% accuracy (AC), 88% negative predictive value (NPV), and 59% positive predictive value (PPV) to diagnose stress-rest perfusion deficits on a per-patient basis. On a per-territory analysis, CT-MPI had 73% SS, 65% SP, 67% AC, 90.8% NPV, and 34% PPV to diagnose perfusion deficits. Conclusions CT-MPI has high sensitivity and good overall accuracy for the diagnosis of functionally significant CAD using 82Rb PET-MPI as the reference standard. CT-MPI may play an important role in assessing the functional significance of CAD especially in combination with CCTA.

Analysis of the iodine distribution map in patients with diagnosis of pulmonary embolism: Initial results

Objectives: Analysing the iodine map distribution in patients with pulmonary embolism diagnosis by Dual Energy Computed Tomography. Materials and methods: Twenty-four images of pulmonary angiotomography by dual energy computed tomography were used to determinate the presence of pulmonary thrombi and identify the perfusion defects (PDs) in the Iodine Maps. Moreover, the iodine density (mg/ml) were measured in normal lung parenchyma and lung parenchyma with PDs areas. The documentary analysis was used thought the data collection sheet and the Likert scale questionnaire. The statistic software SPSS v.25 was used. Results: Thirty-four thrombi were found (21 occlusive and 13 partials occlusive) at monochromatic images. Forty-one perfusion defects (PD) were found at Iodine Maps, these have multiple origins: pulmonary thrombi (69.23%), artifacts (17.95%) and other alterations (12.82%). Furthermore, two new thrombi (5.56%) were identified, both were occlusive and segmental level. Mean Iodine density showed statistically significant differences among normal lung parenchyma (1.65 ± 0.66 mg/ml; [0.77-2.79 mg/ ml]) and parenchyma with PD areas (0.51 ± 0.26 mg/ml; [0.12-1.02 mg/ml])(p=0.000). Mean iodine density also had statistically significant differences between parenchyma with occlusive PD and partial occlusive PD (p=0.000). Iodine Map diagnostic quality was excellent (54.17%), good (33.33%), moderate (12.50%). Conclusion: The Iodine distribution Map offers a benefit greater than 5% in the diagnosis of pulmonary embolism by Dual-Energy Computed Tomography.

Myocardial Perfusion Imaging After Severe COVID-19 Infection Demonstrates Regional Ischemia Rather Than Global Blood Flow Reduction

Background: Acute myocardial damage is common in severe COVID-19. Post-mortem studies have implicated microvascular thrombosis, with cardiovascular magnetic resonance (CMR) demonstrating a high prevalence of myocardial infarction and myocarditis-like scar. The microcirculatory sequelae are incompletely characterized. Perfusion CMR can quantify the stress myocardial blood flow (MBF) and identify its association with infarction and myocarditis.Objectives: To determine the impact of the severe hospitalized COVID-19 on global and regional myocardial perfusion in recovered patients.Methods: A case-control study of previously hospitalized, troponin-positive COVID-19 patients was undertaken. The results were compared with a propensity-matched, pre-COVID chest pain cohort (referred for clinical CMR; angiography subsequently demonstrating unobstructed coronary arteries) and 27 healthy volunteers (HV). The analysis used visual assessment for the regional perfusion defects and AI-based segmentation to derive the global and regional stress and rest MBF.Results: Ninety recovered post-COVID patients {median age 64 [interquartile range (IQR) 54–71] years, 83% male, 44% requiring the intensive care unit (ICU)} underwent adenosine-stress perfusion CMR at a median of 61 (IQR 29–146) days post-discharge. The mean left ventricular ejection fraction (LVEF) was 67 ± 10%; 10 (11%) with impaired LVEF. Fifty patients (56%) had late gadolinium enhancement (LGE); 15 (17%) had infarct-pattern, 31 (34%) had non-ischemic, and 4 (4.4%) had mixed pattern LGE. Thirty-two patients (36%) had adenosine-induced regional perfusion defects, 26 out of 32 with at least one segment without prior infarction. The global stress MBF in post-COVID patients was similar to the age-, sex- and co-morbidities of the matched controls (2.53 ± 0.77 vs. 2.52 ± 0.79 ml/g/min, p = 0.10), though lower than HV (3.00 ± 0.76 ml/g/min, p< 0.01).Conclusions: After severe hospitalized COVID-19 infection, patients who attended clinical ischemia testing had little evidence of significant microvascular disease at 2 months post-discharge. The high prevalence of regional inducible ischemia and/or infarction (nearly 40%) may suggest that occult coronary disease is an important putative mechanism for troponin elevation in this cohort. This should be considered hypothesis-generating for future studies which combine ischemia and anatomical assessment.

Prognostic implication of myocardial perfusion and contractile reserve in end-stage renal disease: A direct comparison of myocardial perfusion scintigraphy and dobutamine stress echocardiography

Background We aimed to compare the prognostic value of myocardial perfusion scintigraphy (MPS) and dobutamine stress echocardiography (DSE) in patients with end-stage renal disease (ESRD) without known coronary artery disease. Methods Two-hundred twenty-nine ESRD patients who applied for kidney transplantation at our centre were prospectively evaluated by MPS and DSE. The primary endpoint was a composite of myocardial infarction (MI) or all-cause mortality. The secondary endpoint included MI or coronary revascularization (CR) not triggered by MPS or DSE at baseline. Results MPS detected reversible ischemia in 31 patients (13.5%) and fixed perfusion defects in 13 (5.7%) patients. DSE discovered stress-induced wall motion abnormalities (WMAs) in 28 (12.2%) and at rest in 18 (7.9%) patients. MPS and DSE results agreed in 85.6% regarding reversible defects (κ = 0.358; P < .001) and in 90.8% regarding fixed defects (κ = 0.275; P < .001). Coronary angiography detected relevant stenosis > 50% in only 15 of 38 patients (39.5%) with pathological findings in MPS and/or DSE. At a median follow-up of 8 years and 10 months, the primary endpoint occurred in 70 patients (30.6%) and the secondary endpoint in 24 patients (10.5%). The adjusted Cox hazard ratios (HRs) for the primary endpoint were 1.77 (95% CI 1.02-3.08; P = .043) for perfusion defects in MPS and 1.36 (95% CI 0.78-2.37; P = ns) for WMA in DSE. The secondary endpoint was significantly correlated with the findings of both modalities, MPS (HR 3.21; 95% CI 1.35-7.61; P = .008) and DSE (HR 2.67; 95% CI 1.15-6.20; P = .022). Conclusion Perfusion defects in MPS are a stronger determinant of all-cause mortality, MI and the need for future CR compared with WMAs in DSE. Given the complementary functional information provided by MPS vs DSE, results are sometimes contradictory, which may indicate differences in the underlying pathophysiology.

Mild cognitive impairment in middle-aged adults with coronary microvascular dysfunction

Introduction Coronary microvascular dysfunction (CMD) may be a manifestation of systemic small vessel disease, including the brain. The prevalence of cognitive impairment in CMD patients is poorly understood. Purpose To assess the prevalence of cognitive impairment in patients with CMD. Methods Between April 2018-March 2020, we enrolled patients with chest discomfort who were admitted to a chest pain observation unit and underwent 3D cardiac positron emission tomography/computed tomography (PET/CT). Exclusions included myocardial infarction, hypertensive urgency, and heart failure. Patients were categorized as 1) Normal: coronary flow reserve (CFR) ≥2.5 without perfusion defect or calcification, 2) Possible CMD: CFR 2–2.5 without perfusion defects or calcification, 3) CMD: CFR &lt;2 without perfusion defects or calcification and 4) coronary artery disease (CAD/CALC): any CFR with perfusion defects or calcifications. We assessed cognitive function with the Montreal Cognitive Assessment (MoCA) and used &lt;23 as the cutoff for impaired cognition. We added 1 point to the total score for those with 12 years of education or less. Odds ratios of cognitive impairment in each group were calculated with the normal group as reference, adjusting for age, sex, and race. Results Of 111 patients consented, 109 patients had complete data for analysis. (Table 1) Mean age was 57 years (± 11), 68% were female, and 49% were non-White. All 11 patients with CMD were females, with a mean age of 59 years (±12). The majority (72%) of CMD patients had cognitive impairment on the MoCA compared to 25% of patients with normal flows (unadjusted OR: 8.00 [95% CI 1.70–37.67]), even after adjustment for age, sex, and race (OR: 37.23 (95% CI 2.01–677.05). MoCA scores did not differ significantly between the normal and the CAD/CALC group (unadjusted OR: 0.95 [95% CI 0.30–3.070]), or the possible CMD group (1.44 [95% CI 0.50–4.14]). Additionally, non-White patients were more likely to demonstrate cognitive impairment on MoCA than White patients (OR: 9.47 [95% CI 3.48–25.81]). There was no significant nonparametric correlation between CFR and the MoCA score (r=0.05, p=0.6). Conclusion Patients with CMD are more likely to have cognitive impairment, supporting the need to further investigate the heart-brain connection in systemic small vessel disease. FUNDunding Acknowledgement Type of funding sources: None.

The Role of Myocardial Perfusion Imaging in Patients with Diabetes Mellitus

Diabetes mellitus is a complex pathology with increasing incidence, associated with an increased risk of coronary heart disease. Myocardial perfusion imaging (MPI) is an important diagnostic tool for the evaluation of coronary artery disease (CAD), with a high prognostic value. Objective. The aim of this study was to evaluate the role of stress-rest MPI in the assessment of patients with DM and suspected or confirmed CAD. Method. We performed a retrospective analysis of 128 patients who underwent stress-rest MPI in our department, all of them with coronary angiography (CA) available. All patients underwent stress rest myocardial perfusion SPECT using a 1-day or 2-day protocol. The radiopharmaceuticals used were 99m-Tc-MIBI or tetrofosmin. The study was performed with a gated protocol SPECT, synchronous with the ECG, using a dual-head gamma camera. Patients were divided in 4 subgroups based on the presence of DM and of significant CA changes. Results. In the group of patients with significant coronary disease on CA and previously diagnosed DM, number of perfusion defects on the stress-rest MPI were higher and also the presence of systolic disfunction and the severity of defects. Our results support the idea that the severity and extent of myocardial perfusion defects are greater in diabetic patients than in non-diabetic patients. Conclusions. We can consider myocardial perfusion SPECT with 99mTc-labeled agents as a feasible method for the diagnosis and evaluation of CAD and for the management of diabetic patients.

Spectral Detector CT-Derived Pulmonary Perfusion Maps And Pulmonary Parenchyma Characteristics For The Semiautomated Classification of Pulmonary Hypertension

Objectives: To evaluate the usefulness of spectral detector CT (SDCT)-derived pulmonary perfusion maps and pulmonary parenchyma characteristics for the semiautomated classification of pulmonary hypertension (PH).Methods: A total of 162 consecutive patients with right heart catheter (RHC)-proven PH of different etiologies as defined by the Nice classification who underwent CT pulmonary angiography (CTPA) on SDCT and 20 patients with an invasive rule-out of PH were included in this retrospective study. Semiautomatic lung segmentation into normal and malperfused areas based on iodine content as well as automatic, virtual noncontrast-based emphysema quantification were performed. Corresponding volumes, histogram features and the ID SkewnessPerfDef-Emphysema-Index (O-index) accounting for the ratio of ID distribution in malperfused lung areas and the proportion of emphysematous lung parenchyma were computed and compared between groups.Results: Patients with PH showed a significantly greater extent of malperfused lung areas as well as stronger and more homogenous perfusion defects. In Nice class 3 and 4 patients, ID skewness revealed a significantly more homogenous ID distribution in perfusion defects than in all other subgroups. The b-index allowed for further subclassification of subgroups 3 and 4 (p < 0.001), identifying patients with chronic thromboembolic PH (CTEPH, subgroup 4) with high accuracy (AUC: 0.92, 95%-CI, 0.85-0.99).Conclusion: Abnormal pulmonary perfusion in PH can be detected and quantified by semiautomated SDCT-based pulmonary perfusion maps. ID skewness in malperfused lung areas, and the j-index allow for a classification of PH subgroups, identifying Nice class 3 and 4 patients with high accuracy, independent of reader expertise.