Williamson, Eric E.

Objectives The aim of this study was to evaluate the high-helical pitch, multienergy (ME) scanning mode of a clinical dual-source photon-counting detector (PCD) computed tomography (CT) and the benefit of virtual monoenergetic images (VMIs) for low-contrast-dose coronary CT angiography (CTA). Materials and Methods High-pitch (3.2) ME coronary CTA was performed in PCD-CT in 27 patients using low contrast dose (30 mL of iohexol 350 mg/mL) and in 26 patients at routine contrast dose (60 mL). Low-energy-threshold 120 kV images (also known as T3D images) and 50 kiloelectron volts (50 keV) and 100 kiloelectron volts (100 keV) VMIs were reconstructed using a 1024 × 1024 matrix and 0.6-mm slices. The CT numbers, noise, and contrast-to-noise ratio (CNR) were measured in the ascending aorta (AA), left main coronary artery (LMCA), and distal left anterior descending (LAD) artery. Confidence in grading luminal stenosis with calcific plaque, noncalcific plaque, and stent was evaluated by 2 independent readers on a 0–100 scale (0 the lowest), and a CAD-RADS score was assigned. Image contrast enhancement, sharpness, noise, artifacts, and overall image quality were rated using a 5-point ordinal scale (1 the lowest). Results The radiation doses (CTDI) in low- and routine-contrast cohorts were 2.5 ± 0.6 mGy and 3.1 ± 1.7 mGy, respectively ( P = 0.12). At all measured locations, the mean CT number was >300 HU in 120 kV (LMCA 382.9 ± 76.2, distal LAD 341.0 ± 53.9, AA 399.5 ± 76.1) and 50 keV images (LMCA 667.5 ± 139.9, distal LAD 578.1 ± 121.5, AA 700.8 ± 142.5) in the low-contrast cohort, with a 96% increase in CT numbers for 50 keV over 120 kV. The CT numbers were significantly higher ( P < 0.0001) in 50 keV than 120 kV and 100 keV VMI. The CNR was also significantly ( P < 0.0001) higher in 50 keV than 120 kV and 100 keV images in all vessels. Confidence in the assessment of luminal stenosis in the presence of calcific plaque was significantly higher ( P = 0.001) with the addition of 100 keV VMI (median score, 100) than using 50 keV alone (median score, 70) and 120 kV (median score, 70) for reader 1, but no significant differences were seen for reader 2 who had same median scores of 100 for all image types. The confidence in the assessment of luminal stenosis within a stent improved with the use of 100 keV images for both readers (reader 1: median scores for 50 + 100 keV = 100, 50 keV = 82.5, 120 kV = 82.5; reader 2: 50 + 100 keV = 100, 50 keV = 90, 120 kV = 90). There were no significant differences in confidence scores for assessment of luminal stenosis from noncalcific plaques for both readers. The reader-averaged qualitative scores for vascular enhancement and overall image quality were significantly higher for 50 keV VMI than for 120 kV images in both low- and routine-contrast dose cohorts. The image sharpness was nonsignificantly higher at 50 keV VMI than 120 kV images, and the artifact score was comparable for 50 keV VMI and 120 kV images. The noise was higher in 50 keV VMI than in 120 kV images. Conclusions High-pitch ME PCD-CT mode produced diagnostic quality coronary CTA images at low radiation and iodinated contrast doses. The availability of ME VMIs significantly improved the CNR, overall image quality, and confidence in assessment of luminal stenosis in the presence of calcific plaques and stents, and resulted in change of CAD-RADS categories in 9 patients.

Abstract Background/Introduction Little is known about the prevalence of high-risk plaque features or cardiometabolic predictors in diverse patient populations with underrepresented minorities, in the setting of stable chest pain. Purpose The goals of our study are to 1) describe plaque characteristics in a diverse patient population with underrepresented minorities and 2) characterize cardiometabolic risk factors associated with high prevalence of high-risk quantitative low attenuation noncalcified plaque (LDNCP) burden. Methods Our study included patients with chest pain undergoing CCTA between June 2016 and October 2021 for stable chest pain, who had a complete cardiometabolic panel including lipoprotein(a) and lipid panel, and at least one blood pressure recording before CCTA. Patients with prior PCI or CABG where excluded. CACS was performed before CCTA as per Agatston method and quantified in Agatston Units (AU). Stenosis was graded as per SCCT guidelines by cardiologists and radiologists with level 3 cardiac CT expertise. Plaque measurements were performed using previously validated semiautomated software (AutoPlaque version 2.5) in all patients with CAD-RADS &gt;0 by expert readers blinded from patients' characteristics. Coronary atherosclerotic plaque volumes were measured. Independent predictors for plaque on CCTA among patients were examined using Wilcox multivariate logistic regression. Results A total of 227 consecutive patients were included in our study (see table; age 55.00 [47.50–62.00] years, 63% female, 16% diabetes, 44% hypertension, 40% hyperlipidemia and 32% with current or previous smoking history). Majority of patients were Hispanic (64%) and the rest were Black (27%), White (6%) and Asian (3%). Patients with LDNCP burden &gt;4% were older (60.00 [52.00–66.50] vs 53.00 [43.75–61.00]; p&lt;0.001), more likely to be diabetic (27.7 vs 11.5%; p=0.005), hypertensive (67.7 vs 33.8%; p&lt;0.001), hyperlipidemic (64.6 vs 29.9%; p&lt;0.001) and present smokers (31.3 vs 13.9%; p=0.003). Almost all patients (63/67) with LDNCP burden &gt;4% had non-obstructive disease (CAD-RADS&lt;4). Patient with LDNCP burden &gt;4% were more likely to be on statin therapy (46.0 vs 30.4%; p=0.041). There was no differences in ethnicity, hemoglobin A1C, TC, LDL-C, HLD-C, TGs, lipoprotein(a), SBP or DBP. By logistic regression analysis, age (OR [CI]: 1.06 [1.01–1.08]), hypertension (2.20, [1.06–4.63]) and hyperlipidemia (2.73 [1.37–5.47]) increased the likelihood of LDNCP burden &gt;4%, but not Lipoprotein (a)&gt;175 nmol/L (OR [CI]: 1.07 [0.48–2.31]. Conclusions In our cohort of patients with high number of unrepresented minorities presenting with stable chest pain, almost all patients (94%) with LDNCP burden &gt;4% had non-obstructive CAD (CAD-RADS&lt;4). There were no differences in prevalence of LDNCP or CAD-RADS among different ethnic groups. Age, hypertension and hyperlipidemia, were the cardiometabolic factors related to LDNCP burden &gt;4%. Funding Acknowledgement Type of funding sources: None.

Background and Purpose: Ultrasound is the most commonly used imaging modality for assessment of carotid artery stenosis. A number of studies have demonstrated that surface irregularities, heterogeneous echotexture and hypoechoic plaques are risk factors for acute ischemic stroke. We performed a systematic review and meta-analysis of the literature to better define the risk of stroke based off of the sonographic characteristics of carotid plaques. Materials and Methods: We performed a comprehensive literature search evaluating the association of carotid plaque characteristics on ultrasound with ischemic outcomes. We included both case-control and cohort studies examining the relationship between complex plaque and acute ischemic stroke. Complex plaque was defined as plaque that had any of the following characteristics: heterogeneous plaque echogenicity, hypoechoic plaque, plaque neovascularization, plaque surface irregularity, plaque ulceration, and intraplaque motion. Meta-analyses using the random-effects model were performed for complex plaque and each of the individual complex plaque characteristics. Results: A total of 1013 articles were screened and 30 studies with 11528 patients (3054 symptomatic and 8474 asymptomatic) were included. The odds ratios for the association between complex plaque and ischemic symptoms was 5.18 (95%CI=4.63-5.79). Heterogeneous echotexture (OR=11.72, 95%CI=9.82-13.98), intraplaque motion (OR=1.57, 95%CI=1.02-2.41), plaque echolucency (OR=3.23, 95%CI=2.72-3.84), plaque neovascularity (OR=5.66, 95%CI=3.15-10.16) and plaque ulceration (OR=2.65, 95%CI=1.89-3.73) were all associated with ischemic symptoms. Surface irregularity without frank ulceration was not associated with ischemic symptoms (OR=1.35, 95%CI=0.98-1.86). Conclusions: Complex plaque, heterogeneous plaque echogenicity, hypoechoic plaque, plaque neovascularization, plaque ulceration and intraplaque motion are associated with ischemic symptoms. Assessment of carotid plaque on ultrasound provides stroke risk information beyond measurement of luminal stenosis.

Introduction: Accurate stroke volume (SV) calculation is critical for calculating aortic valve area by echocardiography. 2D-Doppler estimation of SV (SV 2D ) assumes uniform blood flow velocities through the left ventricular outflow tract (LVOT). Non-uniform flow through the LVOT, appreciated as spectral broadening of the LVOT Doppler signal, could result in inaccurate SV calculation. Hypothesis: Increased spectral broadening in the LVOT will result in overestimation of SV by the SV 2D method compared to 3D volumetric assessment of SV (SV 3D ). Methods: Fifty-one consecutive patients with aortic stenosis underwent comprehensive 2D-TTE and assessment of SV 3D . Patients with ≥ moderate mitral or aortic regurgitation were excluded. An LVOT pulse-wave Doppler signal with > 0.4 m/s difference between outer and inner edge of velocity spectral display (at time of peak velocity) was considered non-uniform flow (i.e., spectral broadening). Results: Spectral broadening was present in 33% of the cohort. These patients were commonly female with smaller ventricles and higher ejection fraction. Spectral broadening was associated with a significant overestimation of SV on Doppler-based measurements (101±20 ml vs 78±15 mL, SV 2D vs SV 3D , respectively; r=0.83, p<0.0001); such differences were not seen in patients with uniform flow velocities (82±15 vs 79±14 mL, r=0.83, p=0.03). Patient characteristics by spectral broadening are shown in table 1. Conclusion: In aortic stenosis patients with non-uniform flow, Doppler-based methods overestimated SV by 29.5% on average (maximum 64%) when compared to 3D methods. This results in a proportional increase in calculated valve area despite a similar mean gradient between groups. Substituting SV 3D resulted in similar SV, valve area, and mean gradient between uniform and non-uniform groups. When spectral broadening >0.40 cm/s is present, 3D volumetric assessment of SV should be considered for accurate estimation of aortic valve area.

Introduction Multi-detector computed tomography (MDCT) is commonly used to identify pulmonary vein and left atrial anatomy prior to catheter ablation for atrial fibrillation (CAAF). Additionally, transesophageal echocardiography (TEE) is utilized to exclude left atrial/left atrial appendage thrombus (ICT). Whether MDCT alone can be used to exclude thrombus obviating the need for TEE is unknown. Methods All Pts referred for CAAF at Mayo Clinic between March 2004 and October 2006 were included. Clinical data (including CHADS score), 64 slice MDCT (non-ECG gated), TEE and intra-cardiac echocardiograph (ICE) were all performed and recorded. Image data was reviewed independently and blinded. The left atrial appendage (LAA) was defined as fully opacified or underfilled. An underfilled LAA was further interrogated using a region of interest over the filling defect and mean attenuation in Hounsfield Units (HU) were recorded. Results In total 400 Pts (mean age 56 ± 10 yrs; 76% male; EF 56 ± 10 % ) were included. 362 had no ICT by TEE nor filling defect by MDCT. 38 patients had an underfilled LAA in whom ICT was confirmed by TEE in 7. Sensitivity and specificity of MDCT for ICT was 100% and 92% respectively with a NPV of 100%. In 19 Pts with underfilled LAA’s, a mean LAA emptying velocity was found to be significantly reduced at 26 cm/s (6 – 61 cm/s). Those with a thrombus had a mean attenuation value below 70 HU. CHADS2 score was higher (2.0 versus 1.0) in Pts with LAA filling defect versus those without LAA filling defect. All Pts with confirmed thrombus were taking Warfarin. ICT was not seen in any Pts aged <52 yrs with CHADS score ≤1. Conclusions Sensitivity and specificity of MDCT for detection of LAA thrombus is high. LAA filling defects on MDCT correlate with low emptying velocities by TEE and low attenuation value in HU. These data would suggest that in the absence of MDCT filling defect, no further imaging is required. TEE should be utilized prior to CAAF to investigate MDCT filling defects. Multidetector Computed Tomography for the Detection of LAA Thrombus

Background: Radiation therapy (RT) to the chest may induce various combined cardiac problems such as constrictive pericarditis (CP), restrictive myocardial disease, and coronary artery disease. Therefore, it was hypothesized that the MRI and transthoracic echocardiographic (TTE) findings in patients with CP may differ according to the history of RT. Methods: A total of 68 patients with CP who performed both TTE and MRI study at Mayo Clinic from 2002 to 2008 were reviewed and divided into two groups according to the history of RT; RT group (group I, n=13, 53.6±9.8 years, 8 males) versus no RT group (group II, n=55, 59.0±14.8, 45 males). Results: The results of TTE study were summarized in table . Early diastolic velocity of septal mitral annulus (E′) and deceleration time (DT) of mitral inflow was significantly lower, and the ratio of early diastolic mitral inflow velocity (E) to E′ is significantly higher in group I than in group II. Left atrial volume index (LAVI) was significantly lower and LA area and left ventricular end-diastolic dimension (LVEDD) was significantly smaller in group I than in group II. Delayed enhancement of pericardium was the only significant finding in MRI and significantly prevalent in group I than in group II (100.0% in group I vs 63.6% in group II, p=0.012). The other MRI findings including pericardial thickness, left ventricular and right ventricular ejection fraction, and the presence of pericardial and pleural effusion were not different between the groups. Conclusion: In CP patients with the history of RT compared to patients without history of RT, E′ and DT was significantly lower, LAVI and LVEDD were smaller, pericardial DE in MRI was invariably found. The lower E′ velocity and decreased chamber size and volumes may be explained by RT induced coexisting myocardial disease. TTE findings of the patients

Objective This study aims to determine if low iodine dynamic computed tomography angiography performed after a fixed delay or test bolus acquisition demonstrates high concordance with clinical computed tomography angiography (using a routine amount of iodinated contrast) to display lower extremity peripheral arterial disease. Methods After informed consent, low iodine dynamic computed tomography angiography examination (using either a fixed delay or test bolus) using 50 ml of iodine contrast media was performed. A subsequent clinical computed tomography angiography using standard iodine dose (115 or 145 ml) served as the reference standard. A vascular radiologist reviewed dynamic and clinical computed tomography angiography images to categorize the lumen into “not opacified”, “<50% stenosis”, “ 50 ̶70% stenosis”, “>70% stenosis”, and “occluded” for seven arterial segments in each lower extremity. Concordance between low iodine dynamic computed tomography angiography and the routine iodine reference standard was calculated. The clinical utility of 4D volume-rendered images was also evaluated. Results Sixty-eight patients (average age 66.1 ± 12.3 years, male; female = 49: 19) were enrolled, with 34 patients each undergoing low iodine dynamic computed tomography angiography using fixed delay and test bolus techniques, respectively. One patient assigned to the test bolus group did not undergo low iodine computed tomography angiography due to unavailable delayed time. The fixed delay was 13 s, with test bolus acquisition resulting in a mean variable delay prior to image acquisition of 19.5 s (range; 8–32 s). Run-off to the ankle was observed using low iodine dynamic computed tomography angiography following fixed delay and test bolus acquisition in 76.4% (26/34) and 100% (33/33) of patients, respectively ( p = 0.005). Considering extremities with run-off to the ankle and without severe artifact, the concordance rate between low iodine dynamic computed tomography angiography and the routine iodine reference standard was 86.8% (310/357) using fixed delay and 97.9% (425/434) using test bolus ( p < 0.001). 4D volume-rendered images using fixed delay and test bolus demonstrated asymmetric flow in 57.7% (15/26) and 58.1% (18/31) ( p = 0.978) of patients, and collateral blood flow in 11.5% (3/26) and 22.6% (7/31) of patients ( p = 0.319), respectively. Conclusion Low iodine dynamic computed tomography angiography with test bolus acquisition has a high concordance with routine peripheral computed tomography angiography performed with standard iodine dose, resulting in improved run-off to the ankle compared to dynamic computed tomography angiography performed after a fixed delay. This method is useful for minimizing iodine dose in patients at risk for contrast-induced nephropathy. 4D volume-rendered computed tomography angiography images provide useful dynamic information.