Mean CT Attenuation Research Articles

Abstract 12314: Clinical Determinants of Low Attenuation Epicardial Adipose Tissue Volume in Type 2 Diabetes

Introduction: The accumulation of excess epicardial adipose tissue (EAT) is associated with the onset of specific heart failure phenotypes. Subsets of adipocytes in EAT produce an inflammatory secretome which alters the extracellular matrix of the epicardium and impairs myocardial contractility. Lipid-laden adipocytes have a low computed tomography (CT) attenuation and can be readily identified using cardiac CT. Objective: This study sought to identify the clinical and biomarker determinants of low attenuation EAT in participants with Type 2 diabetes (T2D) at risk of heart failure. Methods: Participants with T2D and non-diabetic controls were prospectively recruited to an observational multi-modality cardiovascular imaging study. Deep learning analytics (QFAT, Cedars-Sinai) measured EAT volume and CT attenuation from cardiac CT datasets. Adipose tissue with CT attenuation values of -90 to -190 Hounsfield Units (HU) were classified as low attenuation EAT regions. Comparison was made with anthropometric and blood biomarkers to evaluate determinants of low attenuation EAT. Results: Type 2 diabetic (n=151, median age 64 (59, 69) years, 65% male) and non-diabetic individuals (n=39, median age 59 (54, 66.5) years, 59% male) were recruited. Total EAT volume indexed to body surface area was 1.6-fold higher in diabetics (62.4 (49.1, 77.7) cm 3 /m 2 vs 38.8 (29.6, 51.9) cm 3 /m 2 , p <0.01) and mean CT attenuation was lower (-77.4 +/- 5.2 HU vs -70 +/- 5.4 HU, p <0.01). Larger indexed EAT volume was associated with a lower mean CT attenuation in all participants (r = -0.839, p <0.01). Multivariate analysis identified increasing age, white ethnicity and waist circumference as independent determinants of low attenuation EAT (adjusted R 2 = 0.2003, p <0.01). No association was found with dysglycemia (HbA1c, p = 0.2), dyslipidemia (Triglycerides, p = 0.1) and subclinical inflammation (neutrophil:lymphocyte ratio, p = 0.4). Conclusions: In patients with T2D, indexed EAT volumes are 1.6-fold higher with a lower mean CT attenuation. Age, white ethnicity and waist circumference are associated with low attenuation EAT. Prospective studies are required to determine whether interventions to reduce low attenuation EAT will prevent the onset of heart failure.

Physiological significance of pericoronary inflammation in epicardial functional stenosis and global coronary flow reserve

Both fractional flow reserve (FFR) and global coronary flow reserve (g-CFR) provide prognostic information in patients with stable coronary artery disease (CAD). Inflammation plays a vital role in impaired endothelial dysfunction and atherosclerotic progression, potentially predicting cardiovascular mortality. This study aimed to evaluate the physiological significance of pericoronary adipose tissue inflammation assessed by CT attenuation (PCATA) in epicardial functional stenosis severity and g-CFR in patients with CAD. A total of 131 CAD patients with a single de novo epicardial coronary stenosis who underwent coronary CT-angiography (CCTA), phase-contrast cine-magnetic resonance imaging (PC-CMR) and FFR measurement were studied. PCATA was assessed using the mean CT attenuation value. G-CFR was obtained by quantifying absolute coronary sinus flow (ml/min/g) by PC-CMR at rest and during maximum hyperemia. Median FFR, g-CFR, and PCATA values were 0.75, 2.59, and − 71.3, respectively. Serum creatinine, NT-proBNP, left ventricular end-diastolic volume, and PCATA were independently associated with g-CFR. PCATA showed a significant incremental predictive efficacy for impaired g-CFR (< 2.0) when added to the clinical risk model. PCATA was significantly associated with g-CFR, independent of FFR. Our results suggest the pathophysiological mechanisms linking perivascular inflammation with g-CFR in CAD patients.

Association between pericoronary adipose tissue attenuation and outcome after second-generation cryoballoon ablation for atrial fibrillation.

Previous studies reported the association between inflammation and atrial fibrillation (AF). Pericoronary adipose tissue (PCAT) attenuation, PCATA, on cardiac CT angiography (CTA) reflects pericoronary inflammation. We hypothesized that the PCATA predicts AF recurrence after cryoballoon ablation (CBA) for paroxysmal and persistent AF. We studied 364 patients (median age, 65 years) with persistent (n = 41) and paroxysmal (n = 323) AF undergoing successful first-session second-generation CBA with pre-ablation cardiac CTA. Three-vessel (3V)-PCATA was defined as the mean CT attenuation value of PCAT of all three major coronary arteries. Predictors of AF recurrence during follow-up were evaluated. AF recurrence after the 3-month blanking period was detected in 90 patients (24.7%) during the median follow-up of 26 (interquartile range, 19-42) months. AF recurrence was associated with prior stroke and statin use, NT-proBNP and high-sensitivity cardiac troponin-I levels, left ventricular dimension, left atrial volume index (LAVI), 3V-PCATA, and early AF recurrence during the blanking period. On multivariable Cox proportional hazard analysis, prior stroke (hazard ratio [HR], 2.208, 95% confidence interval [CI], 1.166-4.180, p = 0.015), LAVI (HR, 1.030, 95% CI, 1.010-1.051, p = 0.003), 3V-PCATA (HR, 1.034, 95% CI, 1.001-1.069, p = 0.046), and early AF recurrence (HR, 2.858, 95% CI, 1.855-4.405, p < 0.001) remained statistically significant. Pre-ablation CTA-derived 3V-PCATA, representing pericoronary inflammation, was an independent predictor of recurrence after first-session AF ablation using a second-generation cryoballoon. Assessment of 3V-PCATA may identify patients at high risk of AF recurrence after CBA for AF.

Changes in the Mean Intrahepatic Target Computed Tomography Attenuation Value During Treatment May Be a Useful New Predictor of the Post-progression Survival Associated with Lenvatinib Treatment.

Objective The relationship between the prognosis and magnitude of a decrease in tumor blood flow according to estimated tumor differentiation remains unclear. This study investigated the relationship between reductions in the rate of mean computed tomography (CT) attenuation values and the clinical prognosis. Methods We evaluated 63 consecutive patients who received lenvatinib treatment for unresectable hepatocellular carcinoma (HCC). The oncological aggressiveness of the tumors was estimated using classification by dynamic CT enhancement patterns. The utility of changes in mean CT attenuation values of intra-hepatic targets during treatment to estimate the prognosis was investigated by calculating the progression-free survival (PFS) and post-progression survival (PPS). A multivariate analysis was used to identify potential confounders for the survival after progression during lenvatinib therapy. Results The rate of decrease in the mean CT attenuation value gradually increased according to the degree of deterioration in estimated tumor differentiation, and the rate of a decrease in attenuation ≥40% showed a tendency to increase (p=0.064). This trend was reflected by a better objective response in oncological aggressiveness heterogeneous enhancement patterns (Type-3 and Type-4) than a homogeneous enhancement pattern (Type-2) (83% vs. 56% of modified Response Evaluation Criteria in Solid Tumors). This resulted in a similar PFS between the groups (p=0.773), whereas the PPS was significantly worse when the rate of decrease in the attenuation value was ≥40% (p=0.012). A multivariate analysis confirmed that a rate of decease in attenuation value ≥40% was a poor prognostic factor for the PPS (hazard ratio, 2.993; 95% confidence interval, 1.196-7.490; p=0.019). Conclusion A rate of decrease in attenuation ≥40% may reflect a good response of a highly malignant tumor to lenvatinib. Therefore, this value may have utility as a surrogate marker for estimating the oncological aggressiveness of tumors and their associated prognosis.

Computed Tomography-Determined Body Composition Abnormalities Usefully Predict Long-term Mortality in Patients With Liver Cirrhosis.

We evaluated the prognostic impacts of body composition components measured by computed tomography (CT) in patients with liver cirrhosis. A total of 160 cirrhotic patients who underwent CT and hepatic venous pressure gradient measurements were retrospectively enrolled. Cross-sectional areas of skeletal muscle, visceral and subcutaneous fat, and mean CT attenuation of trabecular bone of the fourth lumbar vertebral level (L4HU) were measured. Multivariate analysis showed model for end-stage liver disease score [hazard ratio (HR), 1.086; 95% confidence interval (CI), 1.020-1.156; P = 0.010], hepatic venous pressure gradient (HR, 1.076; 95% CI, 1.021-1.135; P = 0.006), sarcopenia (HR, 1.890; 95% CI, 1.032-3.462; P = 0.039), and L4HU (HR, 1.960 for L4HU <145 Hounsfield units; 95% CI, 1.094-3.512; P = 0.024) were independently associated with long-term mortality. In patients with decompensated cirrhosis, subcutaneous adipose tissue index was the only independent predictor (HR, 0.984; 95% CI, 0.969-0.999; P = 0.039). Body composition abnormalities determined by CT are associated with long-term prognosis in cirrhotic patients.

Computed tomography measured psoas muscle attenuation predicts mortality after transcatheter aortic valve implantation.

The aim of this study was to determine if computed tomography (CT) psoas muscular attenuation measurements may predict all-cause mortality in patients undergoing TAVI. Ninety-four consecutive patients undergoing TAVI were analysed. The CT axial slice at the level of the fourth lumbar vertebra was selected. The psoas muscle areas were manually contoured. The circumferential surface area (CSA) of both psoas muscles was determined by selecting the voxels with attenuation values, ranging from 0 to 100 Hounsfield Units (HU). The mean CT attenuation coefficient of the psoas muscle (Psoas mean HU) was measured. The muscle was subdivided into a low-density muscle (LDM) (0-29 HU) and high-density muscle (HDM) (30-100 HU) portion. The HDM/LDM ratio was calculated. We searched for a correlation between HDM/LDM, CSA LDM (%), Psoas mean HU and all-cause mortality. The mean age was 81.2 ± 7.5 years. Thirty patients had adverse outcome (all-cause mortality). Compared with patients with the lowest CSA LDM (%), patients in the third and second tertiles had an increased hazard ratio for mortality (2.871; 95% confidence interval 0.880-9.371 and 5.044; 95% confidence interval 1.641-15.795, respectively) in a multivariable model with EuroSCORE II, Barthel frailty index and CSA LDM (%) (P = 0.231, 0.097 and 0.019, respectively). HDM/LDM and Psoas mean HU (as continuous variable) were also independent predictors of all-cause mortality (P = 0.019, P = 0.013, respectively). CSA LDM (%), Psoas mean HU and HDM/LDM are independent and incremental predictors of all-cause mortality in patients undergoing TAVI.

Investigation of Three-dimensional Printing Materials for Printing Aorta Model Replicating Type B Aortic Dissection.

This study aims to determine a printing material that has both elastic property and radiology equivalence close to the real aorta for simulation of endovascular stent-graft repair of aortic dissection. With the rapid development of Three-Dimensional (3D) printing technology, a patient- specific 3D printed model is able to help surgeons to make a better treatment plan for Type B aortic dissection patients. However, the radiological properties of most 3D printing materials have not been well characterized. This study aims to investigate the appropriate materials for printing human aorta with mechanical and radiological properties similar to the real aortic Computed Tomography (CT) attenuation. Quantitative assessment of CT attenuation of different materials used in 3D printed models of aortic dissection for developing patient-specific 3D printed aorta models to simulate type B aortic dissection. A 25-mm length of aorta model was segmented from a patient's image dataset with a diagnosis of type B aortic dissection. Four different elastic commercial 3D printing materials, namely Agilus A40 and A50, Visijet CE-NT A30 and A70 were selected and printed with different hardness. Totally four models were printed out and CT scanned twice on a 192-slice CT scanner using the standard aortic CT angiography protocol, with and without contrast inside the lumen. Five reference points with the Region Of Interest (ROI) of 1.77 mm2 were selected at the aortic wall, and intimal flap and their Hounsfield units (HU) were measured and compared with the CT attenuation of original CT images. The comparison between the patient's aorta and models was performed through a paired-sample t-test to determine if there is any significant difference. The mean CT attenuation of the aortic wall of the original CT images was 80.7 HU. Analysis of images without using contrast medium showed that the material of Agilus A50 produced the mean CT attenuation of 82.6 HU, which is similar to that of original CT images. The CT attenuation measured at images acquired with the other three materials was significantly lower than that of the original images (p<0.05). After adding contrast medium, Visijet CE-NT A30 had an average CT attenuation of 90.6 HU, which is close to that of the original images without a statistically significant difference (p>0.05). In contrast, the CT attenuation measured at images acquired with other three materials (Agilus A40, A50 and Visiject CE-NT A70) was 129 HU, 135 HU and 129.6 HU, respectively, which is significantly higher than that of original CT images (p<0.05). Both Visijet CE-NT and Agilus have tensile strength and elongation close to actual patient's tissue properties producing similar CT attenuation. Visijet CE-NT A30 is considered the appropriate material for printing aorta to simulate contrast-enhanced CT imaging of type B aortic dissection. Due to the lack of body phantoms in the experiments, further research with the simulation of realistic anatomical body environment should be conducted.

Microfluidic fabrication of imageable and resorbable polyethylene glycol microspheres for catheter embolization.

Radiopaque and degradable hydrogel microspheres have a range of potential uses in medicine including proper placement of embolic material during occlusion procedures, acting as inherently embolic materials, and serving as drug carriers that can be located after injection. Current methods for creating radiopaque microspheres are either unable to fully and homogeneously incorporate radiopaque material throughout the microspheres for optimal imaging capabilities, do not result in degradable or fully compressible microspheres, or require elaborate, time-consuming preparation. We used a simple one-step microfluidic method to fabricate imageable, degradable polyethylene glycol (PEG) microspheres of varying sizes with homogenous dispersion of barium sulfate-a biocompatible, high-radiopacity contrast agent. The imageability of the microspheres was characterized using optical microscopy and microcomputed tomography as a function of barium sulfate loading. Microspheres with 20%wt/vol barium sulfate had a mean CT attenuation value of 1,510 HU, similar to that of cortical bone, which should enable visualization with soft tissue. Compared with unloaded microspheres, barium sulfate-loaded ones saw an increase in gelation and degradation times and storage modulus and decrease in swelling. Imageable microspheres retained compressibility and were injectable via catheter. The developed radiopaque, degradable PEG microspheres have various potential uses for interventional radiologists and imaging laboratories.

A clinicopathological study of lung adenocarcinomas with pure ground-glass opacity > 3 cm on high-resolution computed tomography.

This study aimed to discuss whether a diameter of 3 cm is a threshold for diagnosing lung adenocarcinomas presenting with radiological pure ground-glass mass (PGGM, pure ground-glass opacity > 3 cm) as adenocarcinomas in situ or minimally invasive adenocarcinomas (AIS-MIAs). Another aim was to identify CT features and patient prognosis that differentiate AIS-MIAs from invasive adenocarcinomas (IACs) in patients with PGGMs. From June 2007 to October 2015, 69 resected PGGMs with HRCT and followed up for ≥ 5 years were included in this study and divided into AIS-MIA (n = 13) and IAC (n = 56) groups. Firth's logistic regression model was performed to determine CT characteristics that helped distinguish IACs from AIS-MIAs. The discriminatory power of the significant predictors was tested with the area under the receiver operating characteristics curve (AUC). Disease recurrence was also evaluated. Univariable and multivariable analyses identified that the mean CT attenuation (odds ratio: 1.054, p = 0.0087) was the sole significant predictor for preoperatively discriminating IACs from AIS-MIAs in patients with PGGMs. The CT attenuation had an excellent differentiating accuracy (AUC: 0.981), with the optimal cut-off value at -600 HU (sensitivity: 87.5%; specificity: 100%). Additionally, no recurrence was observed in patients manifesting with PGGMs > 3 cm, and the 5-year recurrence-free survival and overall survival rates were both 100%, even in cases of IAC. This study demonstrated that PGGMs > 3 cm could still be AIS-MIAs. When PGGMs are encountered in clinical practice, the CT value may be the only valuable parameter to preoperatively distinguish IACs from AIS-MIAs. • Patients with pure ground-glass opacity > 3 cm in diameter are rare but can be diagnosed as adenocarcinomas in situ or minimally invasive adenocarcinomas. • The mean CT attenuation is the sole significant CT parameter that differentiates invasive adenocarcinoma from adenocarcinoma in situ or minimally invasive adenocarcinoma in patients with pure ground-glass opacity > 3 cm. • Lung adenocarcinoma with pure ground-glass opacity > 3 cm has an excellent prognosis, even in cases of invasive adenocarcinoma.

Comprehensive characterization of genomic and radiologic features reveals distinct driver patterns of RTK/RAS pathway in pulmonary nodules presenting as ground-glass opacity.

e20516 Background: GGO-associated pulmonary nodule has been known as radiological appearances of early stage and exhibit more indolent biological behavior. The correlation of different driver gene and radiological features remain poorly understood. Methods: We performed high-depth sequencing of 334 resected pulmonary nodules presenting as GGO from 262 Chinese patients with a custom 1021-gene panel. 130 were multiple pulmonary nodules from 58 patients (2-4 samples per patient). Clinical-pathologic and radiologic parameters of these pulmonary nodules were collected. Immunohistochemistry and multiplex immunofluorescent staining were applied to analyze proliferation and immune cell markers of GGO-associated pulmonary nodules. Results: Mixed GGO enriched in the pathology of invasive LUAD comparing to pure GGO (182/216 vs 73/118, p &lt; 0.001). 88.0% (294/334) of GGO-associated nodules carried at least one gene mutation in EGFR/ERBB2/BRAF/KRAS/MAP2K1 of the RTK/RAS signaling pathway and these driver genes were mutual exclusive to each other. T790M mutation was detected in one patient who had a nodule with CTR &gt; 0.5 and was pathologically defined as MIA. 96.4% (54/56) multiple pulmonary nodules from the same patients showed distinct oncogenic alterations, but 72.4% (42/58) patients carried at least one mutant gene in RTK/RAS pathway across each pulmonary nodule. Nodules with ERBB2/ BRAF/ MAP2K1 mutations tended to be more indolent than those with EGFR and KRAS mutations, showing fewer mutations in radiology status of mGGO or pathology of invasive LUAD. KRAS-mutant subgroup possessed the highest expression of Ki-67 and PD-L1, more infiltration of CD4+ T cell and CD8+T cell. The second highest Ki67-expression was in EGFR-mutant subgroup, together with more CD8+T cell. For EGFR-mutant nodules, co-mutations with TP53 or RBM10 enriched in nodules with CTR &gt; 0.5 and showing higher values of mean CT attenuation and TMB, which may relate to GGO evolution or invasiveness progression. Conclusions: This study elucidated a comprehensive genomic landscape of Chinese radiologically detected GGO-associated pulmonary nodules and highlighted different driver patterns of RTK/RAS pathway corresponding to radiologic features. Our findings provided valuable insight for further research on driver event of RTK/RAS pathway and cancer interception of GGO-associated pulmonary nodules.

Acute necrotising pancreatitis: measurements of necrosis volume and mean CT attenuation help early prediction of organ failure and need for intervention.

This study explored the early predictive value of volume and mean CT density of necrosis for adverse outcomes in patients with acute necrotising pancreatitis (ANP). A total of 155 patients with ANP who underwent CECT within 7 days of symptom onset were included. The necrosis volume, mean CT density, and modified CT severity index (mCTSI) were calculated. C-reactive protein (CRP) and blood urea nitrogen (BUN) levels both 48 h after symptom onset were reviewed. Adverse outcomes were recorded. The predictive value of each indicator was assessed using ROC curve analysis. There were significant associations between necrosis volume and mean CT density and organ failure (OF), persistent OF (POF), and need for intervention (p < 0.001 for all). For predicting OF, the area under the curve (AUC) was significantly higher for necrosis volume than for mCTSI and BUN (AUC: 0.84 vs 0.67, p = 0.0011; 0.84 vs 0.71, p = 0.0193, respectively). For predicting POF and need for intervention, the AUCs for necrosis volume were significantly higher than those for mCTSI (AUC: 0.79 vs 0.66, p = 0.0045; 0.77 vs 0.61, p = 0.0019, respectively), but did not significantly differ from those for CRP and BUN. For predicting OF, a significantly better predictive value was achieved with mean CT density than with mCTSI (AUC: 0.79 vs 0.67, p = 0.0163). There were no significant differences in predictive value between mean CT density, CRP, and BUN. The volume and mean CT density of necrosis based on CECT can provide early prediction of OF, POF, and need for intervention. • Compared to mCTSI, necrosis volume might be used to more accurately diagnose organ failure and persistent organ failure and might be better associated with the need for intervention. • Necrosis volume and mean CT density based on CECT are reliable quantitative predictors for organ failure, persistent organ failure, and intervention in acute pancreatitis.

Comparison of radiation dose, contrast enhancement and image quality of prospective ECG-Gated CT coronary angiography: Single versus dual source CT

IntroductionThe updated National Institute of Clinical Excellence (NICE) guidelines of 2017 state that new generation cardiac CT scanners (Aquilion ONE, Brilliance iCT, Discovery CT750 HD and Somatom Definition Flash) are recommended as an option for first-line imaging of the coronary arteries in people with suspected stable coronary artery disease (with an estimated likelihood of coronary artery disease of 10–29%) in whom imaging with earlier generation CT scanners is difficult. New generation cardiac CT scanners are also recommended as an option for first-line evaluation of disease progression, to establish need for revascularisation in people with known coronary artery disease in whom imaging with earlier generation CT scanners is difficult. CT scanning might not be necessary in situations in which immediate revascularisation is being considered. The European Society of Cardiology 2019 clinical practice guidelines recommend non-invasive functional imaging for myocardial ischaemia or coronary CT angiography (CTA) as the initial test to diagnose CAD in symptomatic patients in whom obstructive CAD cannot be excluded by clinical assessment alone. Given increased computed tomography coronary angiogram (CTCA) utilisation, radiation dose, contrast enhancement and image quality of prospective ECG-gated CTCA between 256-slice single-source and 192x2-slice dual-source CT scanners were retrospectively evaluated. MethodsProspectively gated CTCA data from 63 patients on a 256-slice CT (group A) and 71 patients on a 192x2-slice dual source CT (group B) from January to December 2016 were retrospectively evaluated respectively. Scanner-reported dose length product values were used with a conversion factor (k = 0.014 mSv/mGy x cm) to estimate effective dose. Contrast enhancement was assessed with mean CT attenuation at selected regions of interest on axial coronary images. Image quality of the coronary arteries was assessed by a 4-point grading score (1 = non-diagnostic, 4 = excellent image quality). ResultsThe radiation doses in group B were significantly lower than group A (3.68 + 2.13 mSv versus 4.81 + 1.56 mSv, p < 0.001). There were no significant differences in contrast enhancement in the left coronary artery, proximal right coronary artery and left ventricular wall for both groups. Vessel image quality scores for group B were higher than group A (right coronary artery (RCA): 3.2 + 0.7 versus 2.4 + 0.7, p < 0.001; left anterior descending (LAD) artery: 3.0 + 0.8 vs 2.5 + 0.6, p < 0.001; left circumflex (LCx) artery: 3.3 + 0.7 vs 2.6 + 0.6, p < 0.001). Coronary artery contour scores for group B were significantly higher than group A (RCA: 3.2 + 0.8 versus 2.3 + 0.7, p < 0.001; LAD: 3.0 + 0.7 versus 2.4 + 0.6, p < 0.001; LCx: 3.3 + 0.6 versus 2.5 + 0.6, p < 0.001). ConclusionProspective ECG-gated CTCA performed on 192x2-slice CT results in better image quality and lower radiation dose than 256-slice CT. There were no significant differences in contrast enhancement in left main coronary artery (LMCA), proximal RCA and left ventricular wall in both groups. Implications for practiceIn institutions with both 256-slice and 192x2-slice CT scanners, we recommend that CTCAs be preferentially performed using the 192x2-slice CT scanner.

Use of radiomics to differentiate left atrial appendage thrombi and mixing artifacts on single-phase CT angiography.

To assess if radiomics can differentiate left atrial appendage (LAA) contrast-mixing artifacts and thrombi on early-phase CT angiography without the need for late-phase images. Our study included 111 patients who underwent early- and late-phase, contrast-enhanced cardiac CT. Of these, 79 patients had LAA filling defects from thrombus (n = 46, mean age: 72 ± 12 years, M:F 26:20) or contrast-mixing artifact (n = 33, mean age: 71 ± 13 years, M:F 21:12) on early-contrast-enhanced phase. The remaining 32 patients (mean age: 66 ± 10 years, M:F 19:13) had homogeneous LAA opacification without filling defects. The entire LAA volume on early-phase CT images was manually segmented to obtain radiomic features (Frontier, Siemens). A radiologist assessed for the presence of LAA filling defects and recorded the size and mean CT attenuation (HU) of filling defects and normal LAA. The data were analyzed using multiple logistic regression with receiver operating characteristics area under the curve (AUC) as an output. The radiologist correctly identified all 32 patients without LAA filling defects, 42/46 LAA with thrombi, and 23/33 contrast mixing artifacts. Although HU of LAA thrombi and contrast mixing artifacts was significantly different, with the lowest AUC (0.66), it was inferior to both radiologist assessment and radiomics (p = 0.05). Combination of radiologist assessment and radiomics (AUC 0.92) was superior to HU (0.66), radiomics (0.85), and radiologist (0.80) alone (p < 0.008). Radiomics can differentiate between LAA filling defects from thrombi and contrast mixing artifacts on early-phase contrast-enhanced CT images without the need for late-phase CT.

Quantifying invasiveness of clinical stage IA lung adenocarcinoma with computed tomography texture features

ObjectivesThe study objectives were to establish and validate a nomogram for pathological invasiveness prediction in clinical stage IA lung adenocarcinoma and to help identify those potentially unsuitable for sublobar resection–based computed tomography texture features. MethodPatients with clinical stage IA lung adenocarcinoma who underwent surgery at Guangdong Provincial People's Hospital between January 2015 and October 2018 were retrospectively reviewed. All surgically resected nodules were pathologically classified into less-invasive and invasive cohorts. Each nodule was manually segmented, and its computerized texture features were extracted. Clinicopathological and computed tomographic texture features were compared between 2 cohorts. A nomogram for distinguishing the pathological invasiveness was established and validated. ResultsAmong 428 enrolled patients, 249 were diagnosed with invasive pathological subtypes. Smoking status (odds ratio, 2.906; 95% confidence interval, 1.285-6.579; P = .011), mean computed tomography attenuation value (odds ratio, 1.005, 95% confidence interval, 1.002-1.007; P < .001), and entropy (odds ratio, 8.536, 95% confidence interval, 3.478-20.951; P < .001) were identified as independent predictors for pathological invasiveness by multivariate logistics regression analysis. The nomogram showed good calibration (P = .182) with an area under the curve of 0.849 when validated with testing set data. Decision curve analysis indicated the potentially clinical usefulness of the model with respect to treat-all or treat-none scenario. Compared with intraoperative frozen-section, the nomogram performed better in pathological invasiveness diagnosis (area under the curve, 0.815 vs 0.670; P = .00095). ConclusionsWe established and validated a nomogram to compute the probability of invasiveness of clinical stage IA lung adenocarcinoma with great calibration, which may contribute to decisions related to resection extent.

Pericoronary adipose tissue inflammation on coronary computed tomography in patients with vasospastic angina

Abstract Background A recent study has demonstrated that coronary spasm is associated with inflammation of peri-coronary adipose tissue (PAT) by using the combination of 18F-fluorodeoxyglucose positron emission tomography and computed tomography (CT). PAT attenuation (FAI) on CT angiography (CTA) has been reported to reflect PAT inflammation. We sought to investigate if FAI on CTA was associated with coronary vasospasm in patients with suspected vasospastic angina (VSA). Methods A total of 88 patients who underwent CTA and acetylcholine provocation test (SPT) for suspected VSA were retrospectively investigated. FAI was assessed by the crude analysis of the mean CT attenuation value of 3 major coronary arteries on CTA. FAI was evaluated for the proximal reference diameter (FAI-Ref) and inner 2mm adipose tissue layer (FAI-2mm) from the vessel wall. Diagnosis of VSA (VSA group) was made by SPT and the subjects with negative SPT without organic coronary lesions served as non-VSA group. Association between VSA diagnosis and FAI was assessed and the predictors of VSA was explored by univariable and multivariable analyses. Results In 45 patients (51.1%), VSA was diagnosed (VSA group). There were no significant differences in baseline characteristics between the VSA and non-VSA groups. RCA-FAI was significantly higher in patients of VSA group than in non-VSA group. RCA-FAI-2mm provided significantly better diagnostic performance for VSA than RCA-FAI-Ref and LCA-derived FAI values. Furthermore, RCA-FAI-2mm showed a significant relationship with the severity of spasm evaluated by most stenotic segment diameter during SPT. (r=−0.28, p&amp;lt;0.001) Multivariable logistic regression analysis revealed that RCA-FAI-2mm was an independent predictor of predicting VSA (P&amp;lt;0.001). Conclusion Coronary spasm may be linked with PAT inflammation detected by CTA-derived RCA-FAI, particularly by inner PAT assessment close to the vessel wall. Representative cases for FAI analyses Funding Acknowledgement Type of funding source: None

Clinical significance of the periaortic adipose tissue inflammation in patients with abdominal aortic aneurysms

Abstract Background Recent studies have reported the association between periaortic adipose tissue volumes identified by multi-detector computed tomography (MDCT) and the periaortic adipose tissue inflammation (PATI) identified by positron emission tomography, which may suggest the link between perivascular inflammation and aortic dilation. However, clinical significance of the PATI identified by MDCT remains elusive in patients with asymptomatic abdominal aortic aneurysm (AAA). Methods A total of 77 patients with AAA (diameter &amp;gt;30mm) who underwent the initial and follow-up MDCT examinations were studied retrospectively. PATI was assessed by the crude analysis of the mean CT attenuation value (−190 to −30 Hounsfield units; higher values indicating inflammation). The AAA progression (AP) was defined as the growth of AAA diameter &amp;gt;5.0mm/year from the initial to follow-up. Univariate and multivariate logistic regression analysis were performed to determine the predictors for AP. Results AP was observed in 19 (24.7%) patient, the median initial AAA diameter was 38.9 (32.7–42.9) mm, and the median progression of AAA diameter was 3.1 (1.5–4.9) mm/year. The initial AAA diameter (odds ratio [OR]: 1.16; 95% confidence interval [CI]: 1.05–1.28; p-value=0.001) and the initial PATI (OR: 1.12; 95% CI: 1.05–1.20; p-value=0.004) were independent predictors of AP. PATI of −71.08 at initial MDCT and the initial AAA diameter of 37.7mm were the best cut-off value to predict AP. Receiver operating characteristic curve analysis revealed that the best cut-off values of PATI at initial MDCT and the initial AAA diameter for predicting AP were −71.08 (AUC: 0.68, 95% CI: 0.50–0.82) and 37.7 (AUC: 0.71, 95% CI: 0.59–0.84), respectively. Addition of the initial AAA diameter to PATI at initial MDCT significantly increased the accuracy for discriminating AP (net reclassification improvement; 95% CI: 0.67 [0.17–1.17]; p-value = 0.007, integrated discrimination improvement; 95% CI: 0.14 [0.04–0.24]; p-value =0.007). Conclusions PATI was an independent and significant predictor of aortic dilation, supporting the notion that local adipose tissue inflammation may contribute to aortic remodeling. Comprehensive assessment of MDCT including PATI evaluation may provide a highly accurate information for identifying high risk lesions potentially leading to future AAA rupture. Funding Acknowledgement Type of funding source: None

Impact of pericoronary inflammation assessed by coronary computed tomography angiography on the progression of aortic valve calcification

Abstract Background Aortic valve calcification (AVC) has been known as an independent predictor for adverse cardiovascular events and all-cause mortality. Previous studies demonstrated that AVC was associated with aortic valve inflammation and atherosclerosis. However, the relationship between the progression of AVC and pericoronary inflammation remains undetermined. Purpose The purpose of this study was to evaluate the impact of the pericoronary inflammation on the progression of AVC. Methods A total of 107 patients with suspected or known chronic coronary syndromes who underwent clinically indicated serial 320-slice coronary computed tomography angiography (CTA) at Tsuchiura Kyodo General Hospital from January 2011 to June 2019 were retrospectively studied. Pericoronary inflammation was assessed by pericoronary adipose tissue attenuation (PCATA) defined as the mean CT attenuation value of PCATA (−190 to −30 Hounsfield units [HU]) on proximal 40 mm segments of coronary arteries. AVC was quantified by Agatston score on CTA. The mean aortic attenuation (HU Aorta) and the standard deviation (SD) in the region of interest at the level of the sinotubular junction was measured. AVC was defined as the threshold for calcium detection (mean HU Aorta + 2SD). AVC index was calculated as follows: (follow-up/baseline) AVC divided by follow-up period. AVC progression was defined as newly-developed AVC at follow-up or an increased AVC index during follow-up. All patients were divided into two groups according to the presence or absence of AVC progression, and clinical characteristics and CT findings were compared between these two groups. Results AVC progression was observed in 26 patients (24.3%) between 2 serial CT examinations (median, 34 months). There was no significant difference in age, gender and the prevalence of other cardiovascular risk factors between the 2 groups. Patients in AVC progression group were associated with higher prevalence of elevated PCATA-LAD, higher LV mass index at baseline and the initial AVC presence. Receiver-operating characteristic curve analysis revealed that the optimal cut off value of PCATA-LAD for predicting AVC progression was −68.26 HU (area under the curve 0.605; 95% confidence interval [CI], 0.465–0.745). Multivariable logistic regression analysis revealed that baseline PCATA-LAD ≥−68.26 HU (odds ratio [OR], 3.12; 95% CI, 1.04–9.35, p=0.042) and the presence of baseline positive AVC (OR, 6.84; 95% CI, 2.34–20.0, p=0.0004) were independent predictors of AVC progression. Conclusions The increased pericoronary inflammation and the presence of AVC may help identify patients with high risk for future AVC progression. Funding Acknowledgement Type of funding source: None

Prognostic value of peri-coronary adipose tissue attenuation and whole vessel and lesion plaque quantification on Coronary Computed Tomography Angiography

Abstract Background Peri-coronary adipose tissue attenuation expressed by fat attenuation index (FAI) on coronary CT angiography (CCTA) reflects peri-coronary inflammation and is associated with cardiac mortality. CCTA also provides two-dimensional and three-dimensional quantification of the individual component of atherosclerotic plaque and entire vessel. The atherosclerotic burden or disease extent in entire epicardial coronary arteries provides prognostic information in patients with coronary artery disease. Purpose This study sought to explore the prognostic significance of FAI values and whole vessel and lesion plaque quantification on CCTA in stable patients with intermediate epicardial stenosis evaluated by fractional flow reserve (FFR). Methods A total of 277 patients (277 lesions) with intermediate coronary stenosis who underwent FFR measurement and CCTA were studied. FAI was assessed by the crude analysis of the mean CT attenuation value (−190 to −30 Hounsfield units; higher values indicating inflammation) on CCTA. CT findings including whole vessel and lesion plaque quantification, and target vessel myocardial mass were investigated. Major adverse cardiovascular outcome (MACE) was defined as all cause death, cardiac death, myocardial infarction, unplanned revascularization, and heart failure requiring admission. Survivals from MACE were assessed. Results The mean FAI and the median FFR values were −71.6 and 0.77, respectively. FFR values were weakly albeit significantly correlated with FAI values. (r=−0.016, P=0.008.) MACE was occurred 43 (15.5%) patients during 5 years F-up. ROC analyses revealed that best cut-off value of FAI to predict MACE was −73.1. Kaplan-Meier analysis revealed that lesions with FAI ≥−73.1 had a significantly higher risk of MACE. (Chi-square 5.5, P=0.019) FFR values and the percutaneous coronary intervention were not predictive of MACE. Multivariate COX proportional hazards regression analysis revealed that age, remodeling index, and lesions with FAI ≥−73.1 were independent predictors of MACE. Conclusion The peri-coronary inflammation evaluated by FAI and CT remodeling index enhances cardiac risk prediction in chronic coronary syndrome patients with intermediate lesions. Non-invasive comprehensive CT assessment may help identify high risk patients of subsequent clinical events and provide enhanced patient management. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): This study was supported in part by an unrestricted research grant from St. Jude Medical (Abbot Vascular, Santa Clara, CA, USA). The company had no role in study design, conduct, data analysis or manuscript preparation.

Prognostic value of fat attenuation index of pericoronary adipose tissue surrounding left anterior descending artery on coronary computed tomography angiography

Abstract Background Recent studies reported the association between elevated fat attenuation index (FAI) of pericoronary adipose tissue (PCAT) on coronary computed tomography angiography (CTA) and worse cardiac outcomes. Purpose We investigated the prognostic value of increased FAI-defined coronary inflammation status in patients with coronary artery disease. Methods Three-hundred fifty-eight patients (127 acute coronary syndromes [ACS], 231 stable coronary artery disease) with left anterior descending artery (LAD) as a culprit vessel who underwent coronary CTA were retrospectively studied. The FAI defined as the mean CT attenuation value of PCAT (−190 to −30 Hounsfield Unit [HU]) was measured at the proximal 40-mm segment of LAD. All subjects were divided into two groups according to the median value of FAI in the LAD. The association between the incidence of major adverse cardiac events (MACE) including all-cause death, myocardial infarction, heart failure, target and non-target vessel revascularization were evaluated. Results In a total of 358 patients, median FAI values surrounding the LAD was −71.46 (interquartile range, −77.10 to −66.34) HU. Thirty-eight patients (10.6%) experienced MACE during the follow-up period (median, 818 days). Kaplan-Meier analysis revealed that high FAI-LAD (&amp;gt;−71.46 HU [median]) was significantly associated with the incidence of MACE (log-rank test, chi-square = 4.183, P=0.041) (Figure). Conclusions In patients with coronary artery disease with culprit LAD lesions, elevated FAI of PCAT surrounding the LAD was associated with worse clinical outcomes. Assessment of FAI may have a potential for potential for non-invasive risk-stratification by coronary CTA. Kaplan-Meier analysis for MACE Funding Acknowledgement Type of funding source: None

Association between near-infrared spectroscopy defined lipid rich plaque and pericoronary adipose tissue inflammation on computed tomography angiography

Abstract Background A recent study has shown that lipid-rich plaque (LRP) detected by near-infrared spectroscopy (NIRS) is a significant predictor of future adverse events. Pericoronary adipose tissue inflammation (FAI; fat attenuation index) evaluated by computed tomography angiography (CTA) has also been reported to be linked with cardiac events. The relationship between NIRS-defined LRP and FAI remains to be determined. Methods A total of 82 de novo culprit lesions in 82 patients with chronic coronary syndromes (CCS) who underwent perprocedural CTA and NIRS was retrospectively studied. FAI was assessed by the crude analysis of the mean CT attenuation value (−190 to −30 Hounsfield units; higher values indicating inflammation) of pericoronary adipose tissue. Plaque morphology was assessed by coronary CTA and grey-scale intravascular ultrasound (IVUS). NIRS-defined LRP was defined as a maximum lipid core burden index (LCBI) in 4 mm ≥400. Relationship between NIRS-defined LRP, CTA/grey-scale IVUS findings, and FAI was assessed. Univariate and multivariate logistic regression analyses were performed to determine the predictors for NIRS-derived LRP. Results NIRS-defined LRP was observed in 35 (42.6%) patients. Maximum LCBI showed modest correlations both with FAI (r=0.29, p-value=0.007) and CT-derived remodeling index (r=0.51, p&amp;lt;0.001). Receiver operating characteristic (ROC) curve analysis revealed that the best cut-off values of FAI and CT-derived remodeling index for predicting NIRS-defined LRP were −70.7 (AUC: 0.65, 95% CI: 0.53–0.71, P&amp;lt;0.05) and 1.11 (AUC: 0.74, 95% CI: 0.63–0.86, P&amp;lt;0.01), respectively. Multivariate logistic regression analysis showed FAI ≥−70.7 (odds ratio [OR]: 4.27; 95% CI: 1.28–14.3; p-value = 0.02) and CT-derived remodeling index (OR: 10.7; 95% CI: 2.99–32.2; p-value &amp;lt;0.001) were independent predictors of the presence of NIRS-defined LRP, whereas there was no statistically significant and independent predictor of IVUS-derived factors for NIRS-defined LRP. When stratified according to the presence or absence of FAI ≥−70.7 and CT-derived remodeling index ≥1.11, 93% of the lesions showed NIRS-derived LRP when both factors were present, and NIRS-derived LRP was safely ruled out (88%) when both factors were absent. Conclusions FAI of the culprit lesion in CCS was an independent predictor of NIRS-defined LRP, supporting the notion that local pericoronary adipose tissue inflammation may correlate to the presence of LRP. Comprehensive assessment of coronary CTA including FAI evaluation may provide a highly accurate information with high sensitivity and specificity for identifying high risk lesions potentially leading to future cardiac events. Funding Acknowledgement Type of funding source: None