Left Atrial Appendage Pseudothrombus Is Associated With Stroke History in Patients With Atrial Fibrillation Undergoing Cardiac Computed Tomography.

BACKGROUND: In nonvalvular atrial fibrillation (NVAF), the left atrial appendage (LAA) is the source of thrombus in up to 90% of patients. LAA pseudothrombus (LAAPT), defined as a filling defect on the initial but not the 60-second delayed acquisition on cardiovascular computed tomography scan (CCT), is a recognized phenomenon in NVAF, with unknown clinical relevance. We aimed to determine the relationship between LAAPT and history of stroke in patients with NVAF. METHODS AND RESULTS: The study included 213 consecutive patients with NVAF undergoing CCT who were assessed for LAAPT. LA and LAA dimensions and LAA morphology correlated with clinical demographics including cardiovascular risk factors, history of stroke, thromboembolic stroke, and transient ischemic attack. Mean age (±SD) was 65.1±10.5 years (range 31-89) and 150 of 213 (70.4%) were men. LAAPT was present in 59 of 213 (27.7%) patients. Greater mean LAA ostium area (5.7 versus 4.5, P<0.001), greater mean LAA ostium area:curved length (0.11 versus 0.08, P<0.001), increased LAA volume (14.0 versus 10.2, P<0.001), and lower mean LAA tortuosity index (1.17 versus 1.38, P<0.001) were all associated with the presence of LAAPT. On multivariable analysis, LAAPT on CCT (odds ratio [OR], 3.20 [95% CI, 1.40-7.20]; P<0.006) and higher CHA2DS2-VASc score (OR, 1.65 [95% CI, 1.16-2.35]; P=0.01) were associated with all strokes, with LAAPT remaining a statistically significant risk factor even after adjustment for CHA2DS2-VASc score. CONCLUSIONS: LAAPT on CCT is common in patients with NVAF. It has a strong positive association with stroke prevalence, even after adjustment for CHA2DS2-VASc score. LAAPT on CCT may potentially allow further stratification for stroke risk, additive to the CHA2DS2-VASc score.

Discrepancy Between Achieved and Vendor-Predicted Ablation Zones in the Lung: Contributing Factors.

PURPOSE: Several factors are known to affect lung ablation zones. Questions remain as to why there are discrepancies between achieved and vendor-predicted ablation zones and what contributing factors can be modified to balance therapeutic effects with avoidance of complications. This retrospective study of lung tumour microwave ablation analyses day 1 post-treatment CT to assess the effects of lesion-specific and operator-dependent factors on ablation zones. METHODS AND MATERIALS: Consecutive patients treated at a tertiary centre from 2018 to 2021 were included. All ablations were performed using a single microwave ablation device under lung isolation. The lung tumours were categorised as primary or secondary, and their "resistance" to ablation was graded according to their locations. Intraprocedural pulmonary inflation was assessed as equal to or less than the contralateral non-isolated lung. Ablation energy was categorised as high, medium, or low. Ablation zone dimensions were measured on day 1 CT and compared to vendor reference charts. Ablations with multiple needle positions or indeterminate boundaries were excluded. RESULTS: A total of 47 lesions in 31 patients were analysed. Achieved long axes are longer than predicted by 5 mm or 14% (p < 0.01) without overall short axis discrepancy. Secondary tumours (p = 0.020), low-resistance location (p < 0.01), good lung inflation (p < 0.01), low (p = 0.003) and medium (p = 0.038) total energy produce lengthened long axes by 4-6 mm or 10-19%. High total energy results in shorter than predicated short axes by 6 mm or 18% (p = 0.010). CONCLUSION: We identified several factors affecting ablation zone dimensions which may have implications for ablation planning and the avoidance of complications.

Pulmonary hypertension: the hallmark of acute COVID-19 microvascular angiopathy?

In situ pulmonary arterial thrombosis in COVID-19 is not visible on CTPA. However, the presence of CT-measured right heart and pulmonary artery dilatation in COVID-19 is likely attributable to this process and may be a possible surrogate for its detection. https://bit.ly/3g7z5TV.

Dual-energy Computed Tomographic Pulmonary Angiography Accurately Estimates Lobar Perfusion Before Lung Volume Reduction for Severe Emphysema.

PURPOSE: To assess if dual-energy computed tomographic pulmonary angiography (DECTPA) derived lobar iodine quantification can provide an accurate estimate of lobar perfusion in patients with severe emphysema, and offer an adjunct to single-photon emission CT perfusion scintigraphy (SPECT-PS) in assessing suitability for lung volume reduction (LVR). MATERIALS AND METHODS: Patients with severe emphysema (forced expiratory volume in 1 s <49% predicted) undergoing evaluation for LVR between May 2018 and April 2020 imaged with both SPECT-PS and DECTPA were included in this retrospective study. DECTPA perfused blood volume maps were automatically segmented and lobar iodine mass was estimated and compared with lobar technetium (Tc99m) distribution acquired with SPECT-PS. Pearson correlation and Bland-Altman analysis were used for intermodality comparison between DECTPA and SPECT-PS. Univariate and adjusted multivariate linear regression were modelled to ascertain the effect sizes of possible confounders of disease severity, sex, age, and body mass index on the relationship between lobar iodine and Tc99m values. Effective radiation dose and adverse reactions were recorded. RESULTS: In all, 123 patients (64.5±8.8 y, 71 men; mean predicted forced expiratory volume in 1 s 32.1 ±12.7%,) were eligible for inclusion. There was a linear relationship between lobar perfusion values acquired using DECTPA and SPECT-PS with statistical significance ( P <0.001). Lobar relative perfusion values acquired using DECTPA and SPECT-PS had a consistent relationship both by linear regression and Bland-Altman analysis (mean bias, -0.01, mean r2 0.64; P <0.0001). Individual lobar comparisons demonstrated moderate correlation ( r =0.79, 0.78, 0.84, 0.78, 0.8 for the right upper, middle, lower, left upper, and lower lobes, respectively, P <0.0001). The relationship between lobar iodine and Tc99m values was not significantly altered after controlling for confounders including symptom and disease severity, age, sex, and body mass index. CONCLUSIONS: DECTPA provides an accurate estimation of lobar perfusion, showing good agreement with SPECT-PS and could potentially streamline preoperative assessment for LVR.

Prevalence of Thrombotic Complications in ICU-Treated Patients With Coronavirus Disease 2019 Detected With Systematic CT Scanning.

OBJECTIVES: Severe coronavirus disease 2019 is associated with an extensive pneumonitis and frequent coagulopathy. We sought the true prevalence of thrombotic complications in critically ill patients with severe coronavirus disease 2019 on the ICU, with or without extracorporeal membrane oxygenation. DESIGN: We undertook a single-center, retrospective analysis of 72 critically ill patients with coronavirus disease 2019-associated acute respiratory distress syndrome admitted to ICU. CT angiography of the thorax, abdomen, and pelvis were performed at admission as per routine institution protocols, with further imaging as clinically indicated. The prevalence of thrombotic complications and the relationship with coagulation parameters, other biomarkers, and survival were evaluated. SETTING: Coronavirus disease 2019 ICUs at a specialist cardiorespiratory center. PATIENTS: Seventy-two consecutive patients with coronavirus disease 2019 admitted to ICU during the study period (March 19, 2020, to June 23, 2020). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: All but one patient received thromboprophylaxis or therapeutic anticoagulation. Among 72 patients (male:female = 74%; mean age: 52 ± 10; 35 on extracorporeal membrane oxygenation), there were 54 thrombotic complications in 42 patients (58%), comprising 34 pulmonary arterial (47%), 15 peripheral venous (21%), and five (7%) systemic arterial thromboses/end-organ embolic complications. In those with pulmonary arterial thromboses, 93% were identified incidentally on first screening CT with only 7% suspected clinically. Biomarkers of coagulation (e.g., d-dimer, fibrinogen level, and activated partial thromboplastin time) or inflammation (WBC count, C-reactive protein) did not discriminate between patients with or without thrombotic complications. Fifty-one patients (76%) survived to discharge; 17 (24%) patients died. Mortality was significantly greater in patients with detectable thrombus (33% vs 10%; p = 0.022). CONCLUSIONS: There is a high prevalence of thrombotic complications, mainly pulmonary, among coronavirus disease 2019 patients admitted to ICU, despite anticoagulation. Detection of thrombus was usually incidental, not predicted by coagulation or inflammatory biomarkers, and associated with increased risk of death. Systematic CT imaging at admission should be considered in all coronavirus disease 2019 patients requiring ICU.

Baseline Results of the West London lung cancer screening pilot study - Impact of mobile scanners and dual risk model utilisation.

OBJECTIVES: The West London lung screening pilot aimed to identify early-stage lung cancer by targeting low-dose CT (LDCT) to high risk participants. Successful implementation of screening requires maximising participant uptake and identifying those at highest risk. As well as reporting pre-specified baseline screening metrics, additional objectives were to 1) compare participant uptake between a mobile and hospital-based CT scanner and 2) evaluate the impact on cancer detection using two lung cancer risk models. METHODS: From primary care records, ever-smokers aged 60-75 were invited to a lung health check at a hospital or mobile site. Participants with PLCOM2012 6-yr risk ≥1.51 % and/or LLPv2 5-yr risk ≥2.0 % were offered a LDCT. Lung cancer detection rate, stage, and recall rates are reported. Participant uptake was compared at both sites (chi-squared test). LDCT eligibility and cancer detection rate were compared between those recruited under each risk model. RESULTS: Of 8366 potential participants invited, 1047/5135 (20.4 %) invitees responded to an invitation to the hospital site, and 702/3231 (21.7 %) to the mobile site (p = 0.14). The median distance travelled to the hospital site was less than to the mobile site (3.3 km vs 6.4 km, p < 0.01). Of 1159 participants eligible for a scan, 451/1159 (38.9 %) had a LLPv2 ≥2.0 % only, 71/1159 (6.1 %) had a PLCOM2012 ≥1.5 % only; 637/1159 (55.0 %) met both risk thresholds. Recall rate was 15.9 %. Lung cancer was detected in 29/1145 (2.5 %) participants scanned (stage 1, 58.6 %); 5/29 participants with lung cancer did not meet a PLCOM2012 threshold of ≥1.51 %; all had a LLPv2 ≥2.0 %. CONCLUSION: Targeted screening is effective in detecting early-stage lung cancer. Similar levels of participant uptake at a mobile and fixed site scanner were demonstrated, indicating that uptake was driven by factors in addition to scanner location. The LLPv2 model was more permissive; recruitment with PLCOM2012 alone would have missed several cancers.

Pulmonary Angiopathy in Severe COVID-19: Physiologic, Imaging, and Hematologic Observations.

Rationale: Clinical and epidemiologic data in coronavirus disease (COVID-19) have accrued rapidly since the outbreak, but few address the underlying pathophysiology.Objectives: To ascertain the physiologic, hematologic, and imaging basis of lung injury in severe COVID-19 pneumonia.Methods: Clinical, physiologic, and laboratory data were collated. Radiologic (computed tomography (CT) pulmonary angiography [n = 39] and dual-energy CT [DECT, n = 20]) studies were evaluated: observers quantified CT patterns (including the extent of abnormal lung and the presence and extent of dilated peripheral vessels) and perfusion defects on DECT. Coagulation status was assessed using thromboelastography.Measurements and Results: In 39 consecutive patients (male:female, 32:7; mean age, 53 ± 10 yr [range, 29-79 yr]; Black and minority ethnic, n = 25 [64%]), there was a significant vascular perfusion abnormality and increased physiologic dead space (dynamic compliance, 33.7 ± 14.7 ml/cm H2O; Murray lung injury score, 3.14 ± 0.53; mean ventilatory ratios, 2.6 ± 0.8) with evidence of hypercoagulability and fibrinolytic "shutdown". The mean CT extent (±SD) of normally aerated lung, ground-glass opacification, and dense parenchymal opacification were 23.5 ± 16.7%, 36.3 ± 24.7%, and 42.7 ± 27.1%, respectively. Dilated peripheral vessels were present in 21/33 (63.6%) patients with at least two assessable lobes (including 10/21 [47.6%] with no evidence of acute pulmonary emboli). Perfusion defects on DECT (assessable in 18/20 [90%]) were present in all patients (wedge-shaped, n = 3; mottled, n = 9; mixed pattern, n = 6).Conclusions: Physiologic, hematologic, and imaging data show not only the presence of a hypercoagulable phenotype in severe COVID-19 pneumonia but also markedly impaired pulmonary perfusion likely caused by pulmonary angiopathy and thrombosis.

Evaluation of High-Pitch Ungated Pediatric Cardiovascular Computed Tomography for the Assessment of Cardiac Structures in Neonates.

PURPOSE: We evaluated a high-pitch, non-electrocardiogram-gated cardiac computed tomographic protocol, designed to image both cardiac and extracardiac structures, including coronary arteries, in a neonatal population (less than 1 year old) that was referred for congenital heart disease assessment and compared it with an optimized standard-pitch protocol in an equivalent cohort. MATERIALS AND METHODS: Twenty-nine high-pitch scans were compared with 31 age-matched, sex-matched, and weight-matched standard-pitch, dosimetrically equivalent scans. The visualization and subjective quality of both cardiac and extracardiac structures were scored by consensus between 2 trained blinded observers. Image noise, signal-to-noise and contrast-to-noise ratios, and radiation doses were also compared. RESULTS: The high-pitch protocol better demonstrated the pulmonary veins (P=0.03) and all coronary segments (all P<0.05), except the distal right coronary artery (P=0.10), with no significant difference in the visualization of the remaining cardiac or extracardiac structures. Both contrast-to-noise and signal-to-noise ratios improved due to greater vessel opacity, with significantly fewer streak (P<0.01) and motion (P<0.01) artifacts. Image noise and computed tomographic dose index were comparable across the 2 techniques; however, the high-pitch acquisition resulted in a small, but statistically significant, increase in dose-length product [13.0 mGy.cm (9.0 to 17.3) vs. 11.0 mGy.cm (9.0 to 13.0), P=0.05] due to greater z-overscanning. CONCLUSIONS: In neonates, a high-pitch protocol improves coronary artery and pulmonary vein delineation compared with the standard-pitch protocol, allowing a more comprehensive assessment of cardiovascular anatomy while obviating the need for either patient sedation or heart rate control.

Clinical and economic consequences of non-cardiac incidental findings detected on cardiovascular computed tomography performed prior to transcatheter aortic valve implantation (TAVI).

Transcatheter aortic valve implantation (TAVI) is an effective treatment option for patients with severe degenerative aortic valve stenosis who are high risk for conventional surgery. Computed tomography (CT) performed prior to TAVI can detect pathologies that could influence outcomes following the procedure, however the incidence, cost, and clinical impact of incidental findings has not previously been investigated. 279 patients underwent CT; 188 subsequently had TAVI and 91 were declined. Incidental findings were classified as clinically significant (requiring treatment), indeterminate (requiring further assessment), or clinically insignificant. The primary outcome measure was all-cause mortality up to 3 years. Costs incurred by additional investigations resultant to incidental findings were estimated using the UK Department of Health Payment Tariff. Incidental findings were common in both the TAVI and medical therapy cohorts (54.8 vs. 70.3%; P = 0.014). Subsequently, 45 extra investigations were recommended for the TAVI cohort, at an overall average cost of £32.69 per TAVI patient. In a univariate model, survival was significantly associated with the presence of a clinically significant or indeterminate finding (HR 1.61; P = 0.021). However, on multivariate analysis outcomes after TAVI were not influenced by any category of incidental finding. Incidental findings are common on CT scans performed prior to TAVI. However, the total cost involved in investigating these findings is low, and incidental findings do not independently identify patients with poorer outcomes after TAVI. The discovery of an incidental finding on CT should not necessarily influence or delay the decision to perform TAVI.

Multidetector computed tomography of congenital aortic abnormalities.

For many years invasive angiographic techniques have been considered as the gold standard for the assessment of large arterial abnormalities. However, the complexities and complications inherent to invasive imaging have meant that more recently non-invasive techniques such as echocardiography, Magnetic Resonance Imaging (MRI) and multidetector CT (MDCT) have been increasingly used in congenital cardiovascular disorders. In particular, MDCT has emerged as a fundamental tool for the diagnosis and pre-surgical work-up of aortic abnormalities due to its high spatial resolution, large area of coverage, and short scan time, and therefore is now one of the most widely used modalities for the detection of congenital abnormalities of the aorta. The purpose of this pictorial review is to review the spectrum of abnormalities of the aorta than can be reliably detected by MDCT both in infants and in adulthood. Abnormalities of the aortic root, ascending aorta, aortic arch, and descending aorta will be described separately.

Great vessel and coronary artery anatomy in transposition and other coronary anomalies: a universal descriptive and alphanumerical sequential classification.

In patients with transposition of the great arteries, the identification of coronary anatomy is fundamental to optimal surgical outcome. A number of classifications describing the coronary vessels' origin and course in transposition of the great arteries have been published. However, all are limited to operative or pathological case series. They are often alphanumeric classifications that do not lend themselves to clinical practice; they do not consider certain important anatomical variations that may increase surgical morbidity and mortality, nor do they fully delineate coronary anatomy or define the relationship to adjacent structures seen with cardiovascular computed tomography. Using cardiovascular computed tomography for illustrative purposes, we propose and validate a universal sequential descriptive classification and an associated alphanumeric classification that may be used for all coronary anomalies with or without associated congenital heart disease.

Prevalence of scoliosis in cystic fibrosis.

BACKGROUND: The prevalence of idiopathic scoliosis in the general pediatric population is reported to be between 0.5% and 3.2%. Previous studies have reported an increased prevalence of scoliosis in children with cystic fibrosis (CF). HYPOTHESIS: The prevalence of scoliosis in CF children is greater than in the normal population. METHODS: Chest X-rays of 319 patients attending the Royal Brompton CF Centre were reviewed. The Cobb angle of any spinal lateral curvature was measured. Scoliosis was defined as a Cobb angle of more than 10°. RESULTS: Median age of the whole group of patients was 10.9 years (range 1.1-18 years), 53% were females. Seven patients (2.2%) had radiological signs of scoliosis, their mean age was 14.5 ± 2.3 years (range: 11.5-18 years), 5 were females. Age at onset of scoliosis was between 5 and 10 years for three patients and over 10 years for the others. All the curves were thoracic and with right convexity: apices between T7 and T9 for the single curves (n = 5) and between T4 and T5 (n = 2) for the double curves. CONCLUSION: CF patients showed a similar prevalence of scoliosis as in the normal population (2.2% vs. 0.5-3.2%). There was the same gender (female) and side (right-sided) predilection as in normal population.

Implications for single phase prospective CT coronary angiography for the diagnosis of significant coronary stenoses in clinical practice.

BACKGROUND: CT coronary angiography (CTA) with 64 slice multi-detector CT (64-MDCT) has assumed an increasing role in clinical practice; however the high radiation dose associated with retrospective ECG-gated CTA has led to suggestions that a low dose prospectively gated strategy may be more appropriate. This study aims to assess the feasibility of this proposed strategy amongst standard referral for CTA in our centre. METHODS: We retrospectively analyzed 200 consecutive clinical CTA studies assessing the number of cardiac phases required to allow full diagnostic visualisation of the coronary tree. We assessed whether the pre-test likelihood of coronary disease, heart rate, heart rate variability and range, current beta-blockers use, coronary calcium score, breathing artefact or study quality affected the number of phases required. RESULTS: 125/200 patients (62.5%) required only a single phase for full diagnostic visualisation of the coronary tree [most commonly 65% of the R-R interval-109/125 (87.2%)]. A successful diagnostic single cardiac phase was most likely in patients with a low heart rate (Heart rate < 70 bpm OR = 2.64; p = 0.003 and heart rate < 60 bpm OR = 4.81; p < 0.001 respectively) and low likelihood of coronary disease [OR = 1.97 95% CI (1.09, 3.58) p = 0.025]. CONCLUSION: High image quality is possible using single phase analysis in those patients with low likelihood of coronary disease, low heart rates and full cooperation with inspiratory breath hold. In patients with HR of <60, prospective ECG-gated acquisitions reduce radiation dose but may be non-diagnostic in as many as one third. Careful patient selection is therefore essential.

Secondary vascular changes in pulmonary sequestrations.

AIMS: Whilst parenchymal changes in pulmonary sequestrations are well described, there are comparatively little data on associated vascular changes and their extent. The aim of this study was to retrospectively review morphological changes within sequestrations, concentrating on vascular changes and associations with clinical parameters. METHODS AND RESULTS: Twenty-seven resected cases of sequestrations (intralobar n = 20, extralobar n = 7) showed a male predominance (n = 16) and an age range of 2 months-60 years (average 13 years). Plexogenic vascular changes (medial hypertrophy and intimal fibrosis) were seen in 15 of 27 cases, as well as plexiform lesions in seven cases. Patients with plexogenic changes had a higher mean age compared with those lacking vascular changes (19 versus 6 years) and were more commonly female. Respiratory tract infections were associated solely with intralobar sequestrations. No other associations between presenting symptoms and histopathological parameters were identified. Adjacent lung showed lesser plexogenic changes in six of 22 intralobar cases. There were features of type 2 congenital cystic adenomatoid lesions in 63% of cases. Dissection of the supplying systemic artery (n = 1), intralesional aspergilloma (n = 1) and coexistent lymphangiomatosis (n = 1) were also identified. CONCLUSIONS: Hypertensive vascular changes are not uncommon in both intrapulmonary and extrapulmonary sequestrations, although their relative severity seems unrelated to presenting symptoms.

X-ray computed tomography of the heart.

INTRODUCTION: Cardiac imaging is an emerging application of multidetector computed tomography (MDCT). This review summarizes the current capabilities, possible applications, limitations and developments of cardiac CT. SOURCES OF DATA: Relevant publications in peer reviewed literature and national and international guidelines are used to discuss important issues in cardiac CT imaging. AREAS OF AGREEMENT AND CONTROVERSY: There is broad consensus that coronary CT angiography is indicated in patients with an intermediate pre-test probability of coronary artery disease (CAD) when other non-invasive tests have been equivocal. In this context, CT can reliably exclude significant CAD. Cardiac CT also has an established role in the evaluation of bypass grafts and suspected coronary anomalies. Radiation exposure from CT procedures remains a concern, although techniques are now available to reduce the X-ray dosage without significantly compromising the image quality. However, with the current level of knowledge, the cardiac CT examinations are not justified to screen for CAD in asymptomatic individuals. Neither is it considered appropriate in patients with a high pre-test probability of CAD, for whom invasive catheter coronary angiography is usually of more benefit. GROWING POINTS AND AREAS TIMELY FOR DEVELOPING RESEARCH: The ability to reconstruct the volumetric cardiac CT data set opens up avenues for advanced physiological analyses of the heart. For example, if CT myocardial perfusion assessment becomes a reality, there is potential to revolutionize the practice of MDCT imaging. Research is also ongoing to investigate whether cardiac CT has a role in the appropriate triage of patients with chest pain in the emergency department.

Defining the appropriate CTA stenosis threshold for gatekeeping to invasive angiography: 50% or 70%?

There is currently much debate around the limited positive predictive value (PPV) of CT coronary angiography (CTA). There remain no published studies comparing different thresholds to define significant visual stenoses on CTA compared to the gold standard quantitative coronary angiography (QCA). The spatial resolution for ICA is (0.1 mm)(3) compared with (0.5 mm)(3) in clinical CTA and direct comparison introduces a systematic overestimation of stenosis severity by CTCA. Assessing both ≥ 50% and ≥ 70% visual stenoses on CTA with QCA we found that the negative predictive value (NPV) of CTA is equally high for both. The PPV of CTA improves using ≥ 70% but with a loss of sensitivity. Using ≥ 70% stenosis on CTA for referral for ICA would reduce the number of ICA that does not lead to percutaneous intervention (PCI) but a functional test for intermediate lesions (visual stenoses of 50%-69%) on CTA is recommended to overcome the reduction in sensitivity.