Deep Learning-based Fibrosis Extent on Computed Tomography Predicts Outcome of Fibrosing Interstitial Lung Disease Independent of Visually Assessed Computed Tomography Pattern.

Rationale: Radiologic pattern has been shown to predict survival in patients with fibrosing interstitial lung disease. The additional prognostic value of fibrosis extent by quantitative computed tomography (CT) is unknown. Objectives: We hypothesized that fibrosis extent provides information beyond visually assessed CT pattern that is useful for outcome prediction. Methods: We performed a retrospective analysis of chest CT, demographics, longitudinal pulmonary function, and transplantation-free survival among participants in the Pulmonary Fibrosis Foundation Patient Registry. CT pattern was classified visually according to the 2018 usual interstitial pneumonia criteria. Extent of fibrosis was objectively quantified using data-driven textural analysis. We used Kaplan-Meier plots and Cox proportional hazards and linear mixed-effects models to evaluate the relationships between CT-derived metrics and outcomes. Results: Visual assessment and quantitative analysis were performed on 979 enrollment CT scans. Linear mixed-effect modeling showed that greater baseline fibrosis extent was significantly associated with the annual rate of decline in forced vital capacity. In multivariable models that included CT pattern and fibrosis extent, quantitative fibrosis extent was strongly associated with transplantation-free survival independent of CT pattern (hazard ratio, 1.04; 95% confidence interval, 1.04-1.05; P < 0.001; C statistic = 0.73). Conclusions: The extent of lung fibrosis by quantitative CT is a strong predictor of physiologic progression and survival, independent of visually assessed CT pattern.

Reference ranges ("normal values") for cardiovascular magnetic resonance (CMR) in adults and children: 2020 update.

Cardiovascular magnetic resonance (CMR) enables assessment and quantification of morphological and functional parameters of the heart, including chamber size and function, diameters of the aorta and pulmonary arteries, flow and myocardial relaxation times. Knowledge of reference ranges ("normal values") for quantitative CMR is crucial to interpretation of results and to distinguish normal from disease. Compared to the previous version of this review published in 2015, we present updated and expanded reference values for morphological and functional CMR parameters of the cardiovascular system based on the peer-reviewed literature and current CMR techniques. Further, databases and references for deep learning methods are included.

Prevalence of left atrial abnormalities in atrial fibrillation versus normal sinus patients.

BACKGROUND: Atrial fibrillation (AF) may be the cause or sequela of left atrial abnormalities and variants. PURPOSE: To determine the prevalence of left atrial (LA) abnormalities in AF patients compared to normal sinus rhythm (NSR) patients. MATERIAL AND METHODS: We retrospectively reviewed 281 cardiac CT examinations from 2010 to 2012, excluding patients with prior pulmonary vein ablation, known coronary artery disease, prior coronary stent placement, or coronary artery bypass grafts. The first group consisted of 159 AF patients undergoing cardiac CT prior to pulmonary vein ablation and the second group consisted of 122 NSR patients evaluated with coronary CT angiography. Demographic data were collected. LA abnormalities were analyzed. Left atrial diameter was measured on an axial view. RESULTS: A total of 281 patients were included. The male gender has significantly higher prevalence of AF than female gender, P value <0.001. Patients with AF were significantly older (mean age, 57.4 years; standard deviation [SD], 11.8 years) than NSR patients (mean age, 53.4 years; SD, 13.6 years), P value, 0.01. The left atrial diameter was greater in the AF patients (mean diameter, 4.3 cm; SD, 0.82 cm) versus the NSR patients (3.4 cm; SD, 0.58 cm), P value, <0.0001. LA diverticulum was the most prevalent variant, occurring in 28.4% of the entire patient population followed by LA pouch, occurring in 24%. There was no significant between group differences in the prevalence of these or the remainder of the LA variants. CONCLUSION: AF patients differed significantly from NSR patients in LA size, gender, and mean age. There was no statistical significance between the two groups with regard to the LA morphologic abnormalities other than size.

A Practice Quality Improvement Project: Reducing Dose of Routine Chest CT Imaging in a Busy Clinical Practice.

The purpose of this report is to describe our experience with the implementation of a practice quality improvement (PQI) project in thoracic imaging as part of the American Board of Radiology Maintenance of Certification process. The goal of this PQI project was to reduce the effective radiation dose of routine chest CT imaging in a busy clinical practice by employing the iDose(4) (Philips Healthcare) iterative reconstruction technique. The dose reduction strategy was implemented in a stepwise process on a single 64-slice CT scanner with a volume of 1141 chest CT scans during the year. In the first annual quarter, a baseline effective dose was established using the standard filtered back projection (FBP) algorithm protocol and standard parameters such as kVp and mAs. The iDose(4) technique was then applied in the second and third annual quarters while keeping all other parameters unchanged. In the fourth quarter, a reduction in kVp was also implemented. Throughout the process, the images were continually evaluated to assure that the image quality was comparable to the standard protocol from multiple other scanners. Utilizing a stepwise approach, the effective radiation dose was reduced by 23.62 and 43.63 % in quarters two and four, respectively, compared to our initial standard protocol with no perceived difference in diagnostic quality. This practice quality improvement project demonstrated a significant reduction in the effective radiation dose of thoracic CT scans in a busy clinical practice.

Compensatory Enlargement of Ossabaw Miniature Swine Coronary Arteries in Diffuse Atherosclerosis.

Studies in human and non-human primates have confirmed the compensatory enlargement or positive remodeling (Glagov phenomenon) of coronary vessels in the presence of focal stenosis. To our knowledge, this is the first study to document arterial enlargement in a metabolic syndrome animal model with diffuse coronary artery disease (DCAD) in the absence of severe focal stenosis. Two different groups of Ossabaw miniature pigs were fed a high fat atherogenic diet for 4 months (Group I) and 12 months (Group II), respectively. Group I (6 pigs) underwent contrast enhanced computed tomographic angiography (CCTA) and intravascular ultrasound (IVUS) at baseline and after 4 months of high fat diet, whereas Group II (7 pigs) underwent only IVUS at 12 months of high fat diet. IVUS measurements of the left anterior descending (LAD), left circumflex (LCX) and right coronary (RCA) arteries in Group I showed an average increase in their lumen cross-sectional areas (CSA) of 25.8%, 11.4%, and 43.4%, respectively, as compared to baseline. The lumen CSA values of LAD in Group II were found to be between the baseline and 4 months values in Group I. IVUS and CCTA measurements showed a similar trend and positive correlation. Fractional flow reserve (FFR) was 0.91±0.07 at baseline and 0.93±0.05 at 4 months with only 2.2%, 1.6% and 1% stenosis in the LAD, LCX and RCA, respectively. The relation between percent stenosis and lumen CSA shows a classical Glagov phenomenon in this animal model of DCAD.

Two-in-one aortic valve sizing and valvuloplasty conductance balloon catheter.

BACKGROUND: Inaccurate aortic valve sizing and selection is linked to paravalvular leakage in transcatheter aortic valve replacement (TAVR). Here, a novel sizing valvuloplasty conductance balloon (SVCB) catheter is shown to be accurate, reproducible, unbiased, and provides real-time tool for aortic valve sizing that fits within the standard valvuloplasty procedure. METHODS AND RESULTS: The SVCB catheter is a valvuloplasty device that uses real-time electrical conductance measurements based on Ohm's Law to size the balloon opposed against the aortic valve at any given inflation pressure. Accuracy and repeatability of the SVCB catheter was performed on the bench in phantoms of known dimension and ex vivo in three domestic swine aortic annuli with comparison to computed tomography (CT) and dilator measurements. Procedural workflow and safety was demonstrated in vivo in three additional domestic swine. SVCB catheter measurements had negligible bias or error for bench accuracy considered as the gold standard (Bias: -0.11 ± 0.26 mm; Error: 1.2%), but greater disagreement in ex vivo versus dilators (Bias: -0.3 ± 1.1 mm; Error: 4.5%), and ex vivo versus CT (Bias: -1.0 ± 1.6 mm; Error: 8.7%). The dilator versus CT accuracy showed similar agreement (Bias: -0.9 ± 1.5 mm; Error: 7.3%). Repeatability was excellent on the bench (Bias: 0.02 ± 0.12 mm; Error: 0.5%) and ex vivo (Bias: -0.4 ± 0.9 mm; Error: 4.6%). In animal studies, the device fit well within the procedural workflow with no adverse events or complications. CONCLUSIONS: Due to the clinical relevance of this accurate, repeatable, unbiased, and real-time sizing measurement, the SVCB catheter may provide a useful tool prior to TAVR. These findings merit a future human study.

MR imaging evaluation of pericardial constriction.

Abnormal thickening or rigidity of the pericardium may compromise normal cardiac function. This condition is known as pericardial constriction, or constrictive pericarditis. Several imaging modalities are used to evaluate the pericardium, including MR, computed tomography, and echocardiography, which can all play a complementary role aiding diagnosis. This article focuses on MR imaging and its role in the detection and evaluation of pericardial constriction. MR imaging has many advantages compared with other modalities including precise delineation of the pericardial thickness, evaluation of ventricular function, detection of wall motion abnormalities, and provision of information about common (and potentially harmful) sequelae of pericardial constriction.

Mass-conserved volumetric lattice Boltzmann method for complex flows with willfully moving boundaries.

In this paper, we develop a mass-conserved volumetric lattice Boltzmann method (MCVLBM) for numerically solving fluid dynamics with willfully moving arbitrary boundaries. In MCVLBM, fluid particles are uniformly distributed in lattice cells and the lattice Boltzmann equations deal with the time evolution of the particle distribution function. By introducing a volumetric parameter P(x,y,z,t) defined as the occupation of solid volume in the cell, we distinguish three types of lattice cells in the simulation domain: solid cell (pure solid occupation, P=1), fluid cell (pure fluid occupation, P=0), and boundary cell (partial solid and partial fluid, 0

Epicardial adipose excision slows the progression of porcine coronary atherosclerosis.

BACKGROUND: In humans there is a positive association between epicardial adipose tissue (EAT) volume and coronary atherosclerosis (CAD) burden. We tested the hypothesis that EAT contributes locally to CAD in a pig model. METHODS: Ossabaw miniature swine (n=9) were fed an atherogenic diet for 6 months to produce CAD. A 15 mm length by 3-5 mm width coronary EAT (cEAT) resection was performed over the middle segment of the left anterior descending artery (LAD) 15 mm distal to the left main bifurcation. Pigs recovered for 3 months on atherogenic diet. Intravascular ultrasound (IVUS) was performed in the LAD to quantify atheroma immediately after adipectomy and was repeated after recovery before sacrifice. Coronary wall biopsies were stained immunohistochemically for atherosclerosis markers and cytokines and cEAT was assayed for atherosclerosis-related genes by RT-PCR. Total EAT volume was measured by non-contrast CT before each IVUS. RESULTS: Circumferential plaque length increased (p<0.05) in the proximal and distal LAD segments from baseline until sacrifice whereas plaque length in the middle LAD segment underneath the adipectomy site did not increase. T-cadherin, scavenger receptor A and adiponectin were reduced in the intramural middle LAD. Relative to control pigs without CAD, 11ß-hydroxysteroid dehydrogenase (11ßHSD-1), CCL19, CCL21, prostaglandin D2 synthase, gp91phox [NADPH oxidase], VEGF, VEGFGR1, and angiotensinogen mRNAs were up-regulated in cEAT. EAT volume increased over 3 months. CONCLUSION: In pigs used as their own controls, resection of cEAT decreased the progression of CAD, suggesting that cEAT may exacerbate coronary atherosclerosis.

Mild anastomotic stenosis in patient-specific CABG model may enhance graft patency: a new hypothesis.

It is well known that flow patterns at the anastomosis of coronary artery bypass graft (CABG) are complex and may affect the long-term patency. Various attempts at optimal designs of anastomosis have not improved long-term patency. Here, we hypothesize that mild anastomotic stenosis (area stenosis of about 40-60%) may be adaptive to enhance the hemodynamic conditions, which may contribute to slower progression of atherosclerosis. We further hypothesize that proximal/distal sites to the stenosis have converse changes that may be a risk factor for the diffuse expansion of atherosclerosis from the site of stenosis. Twelve (12) patient-specific models with various stenotic degrees were extracted from computed tomography images using a validated segmentation software package. A 3-D finite element model was used to compute flow patterns including wall shear stress (WSS) and its spatial and temporal gradients (WSS gradient, WSSG, and oscillatory shear index, OSI). The flow simulations showed that mild anastomotic stenosis significantly increased WSS (>15 dynes · cm(-2)) and decreased OSI (<0.02) to result in a more uniform distribution of hemodynamic parameters inside anastomosis albeit proximal/distal sites to the stenosis have a decrease of WSS (<4 dynes · cm(-2)). These findings have significant implications for graft adaptation and long-term patency.

CT-based diagnosis of diffuse coronary artery disease on the basis of scaling power laws.

PURPOSE: To provide proof of concept for a diagnostic method to assess diffuse coronary artery disease (CAD) on the basis of coronary computed tomography (CT) angiography. MATERIALS AND METHODS: The study was approved by the Cleveland Clinic Institutional Review Board, and all subjects gave informed consent. Morphometric data from the epicardial coronary artery tree, determined with CT angiography in 120 subjects (89 patients with metabolic syndrome and 31 age- and sex-matched control subjects) were analyzed on the basis of the scaling power law. Results obtained in patients with metabolic syndrome and control subjects were compared statistically. RESULTS: The mean lumen cross-sectional area (ie, lumen cross-sectional area averaged over each vessel of an epicardial coronary artery tree) and sum of intravascular volume in patients with metabolic syndrome (0.039 cm(2) ± 0.015 [standard deviation] and 2.71 cm(3) ± 1.75, respectively) were significantly less than those in control subjects (0.054 cm(2)± 0.015 and 3.29 cm(3)± 1.77, respectively; P < .05). The length-volume power law showed coefficients of 27.0 cm(-4/3) ± 9.0 (R(2) = 0.91 ± 0.08) for patients with metabolic syndrome and 19.9 cm(-4/3) ± 4.3 (R(2) = 0.92 ± 0.07) for control subjects (P < .05). The probability frequency shows that more than 65% of patients with metabolic syndrome had a coefficient of 23 or more for the length-volume scaling power law, whereas approximately 90% of the control subjects had a coefficient of less than 23. CONCLUSION: The retrospective scaling analysis provides a quantitative rationale for diagnosis of diffuse CAD.

Computed tomography-based diagnosis of diffuse compensatory enlargement of coronary arteries using scaling power laws.

Glagov's positive remodelling in the early stages of coronary atherosclerosis often results in plaque rupture and acute events. Because positive remodelling is generally diffused along the epicardial coronary arterial tree, it is difficult to diagnose non-invasively. Hence, the objective of the study is to assess the use of scaling power law for the diagnosis of positive remodelling of coronary arteries based on computed tomography (CT) images. Epicardial coronary arterial trees were reconstructed from CT scans of six Ossabaw pigs fed on a high-fat, high-cholesterol, atherogenic diet for eight months as well as the same number of body-weight-matched farm pigs fed on a lean chow (101.9±16.1 versus 91.5±13.1 kg). The high-fat diet Ossabaw pig model showed diffuse positive remodelling of epicardial coronary arteries. Good fit of measured coronary data to the length-volume scaling power law ( where L(c) and V(c) are crown length and volume) were found for both the high-fat and control groups (R(2) = 0.95±0.04 and 0.99±0.01, respectively). The coefficient, K(LV), decreased significantly in the high-fat diet group when compared with the control (14.6±2.6 versus 40.9±5.6). The flow-length scaling power law, however, was nearly unaffected by the positive remodelling. The length-volume and flow-length scaling power laws were preserved in epicardial coronary arterial trees after positive remodelling. K(LV) < 18 in the length-volume scaling relation is a good index of positive remodelling of coronary arteries. These findings provide a clinical rationale for simple, accurate and non-invasive diagnosis of positive remodelling of coronary arteries, using conventional CT scans.

Accurate nonfluoroscopic guidance and tip location of peripherally inserted central catheters using a conductance guidewire system.

BACKGROUND: Bedside placement of peripherally inserted central catheters (PICCs) may result in navigation to undesirable locations, such as the contralateral innominate or jugular vein, instead of the superior vena cava or right atrium. Although some guidance and tip location tools exist, they have inherent limitations because of reliance on physiological measures (eg, chest landmarks, electrocardiogram, etc), instead of anatomical assessment (ie, geometric changes in the vasculature). In this study, an accurate, anatomically based, non-X-ray guidance tool placed on a novel 0.035" conductance guidewire (CGW) is validated for PICC navigation and tip location. METHODS: The CGW system uses electrical conductance recordings to assess changes in vessel cross-sectional area to guide navigation of the PICC tip. Conductance rises and oscillates when going in the correct direction to the superior vena cava/right atrium, but drops when going in the incorrect direction away from the heart. Bench and in vivo studies in six swine were used to confirm the accuracy and repeatability of the PICC placement at various anatomical locations. The PICC tip location was confirmed by direct visualization vs the desired location. RESULTS: CGW PICC guidance was highly accurate and repeatable with virtually no difference between actual and desired catheter tip location. The difference between the CGW PICC location vs the desired target was -0.07 ± 0.07 cm (6.6% error) on the bench and 0.04 ± 0.10 cm (5% error) in vivo. No complications or adverse events occurred during CGW usage. CONCLUSIONS: The CGW provides an anatomically based, reproducible, and clinically significant method for PICC navigation and tip location that can improve accuracy, decrease the wait time prior to therapy delivery, decrease cost, and minimize the need for X-ray. These findings warrant clinical evaluation of this navigation tool for PICC line placement.

Imaging of the coronary sinus: normal anatomy and congenital abnormalities.

Knowledge of the anatomy of the coronary sinus (CS) and cardiac venous drainage is important because of its relevance in electrophysiologic procedures and cardiac surgeries. Several procedures make use of the CS, such as left ventricular pacing, mapping and ablation of arrhythmias, retrograde cardioplegia, targeted drug delivery, and stem cell therapy. As a result, it is more important for physicians interpreting the results of computed tomographic (CT) examinations dedicated to the heart or including the heart to be able to identify normal variants and congenital anomalies and to understand their clinical importance. Abnormalities of the CS range from anatomic morphologic variations to hemodynamically significant anomalies such as an unroofed CS, anomalous pulmonary venous connection to the CS, and coronary artery-CS fistula. It can be important to identify some anatomic variations, even though they are clinically occult, to ensure appropriate preprocedural planning. Both CT and magnetic resonance imaging provide excellent noninvasive depiction of the anatomy and anomalies of the CS. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.324105220/-/DC1.

Learning to interpret the extracardiac findings on coronary CT angiography examinations.

Coronary computed tomography angiography (CTA) plays an important role in the identification of coronary artery disease in low- to intermediate-risk patients. Even with a "restrictive" field of view, coronary CTA data sets will include visualization of structures adjacent to the heart, including the thoracic great vessels, pericardium, mediastinum, lungs, and bones. CT images enable detailed assessment of these structures, at times identifying a potential noncoronary cause of the patient's presenting symptom. The reported incidence of extracardiac findings on coronary CTA is as high as 53%-67%. Complete evaluation of the examination requires scrutiny of the soft tissues, lung tissues, and bones, both in the chest and adjacent abdomen. It is important to adjust the CT window display settings at various stages of the interpretation process to evaluate all potential extracardiac disease. Although in-depth radiology training would be required to correctly identify and interpret all anomalies, this article serves as an overview and guide to evaluation of the extracardiac structures included on a coronary CTA examination. Correct interpretation of extracardiac findings is critical because a false positive interpretation can lead to unnecessary testing and treatment that can be as harmful as a false negative interpretation. Most importantly, if the cardiac findings do not explain the patient's symptoms, an alternative cause should be specifically sought to appropriately manage the patient.

Rate of progression of transthyretin amyloidosis.

Hereditary transthyretin (TTR) amyloidosis is an adult-onset disease characterized mainly by peripheral neuropathy and cardiomyopathy. Although disease progression is usually 5 to 15 years from time of diagnosis to death, no specific measurements of disease progression have been identified. The present study was designed to identify objective parameters to measure progression of hereditary TTR amyloidosis and determine if these parameters would show significant change within 1 year. Nine patients with biopsy-proved TTR amyloidosis and evidence of cardiac involvement were studied at baseline, 6 months, and 12 months by cardiac magnetic resonance imaging (MRI), electrocardiogram, and echocardiogram. Neurologic impairment score and electromyogram were determined at baseline and 12 months. Left ventricular mass determined by MRI and echocardiogram showed significant change at 12-month examination (p = 0.005 and p = 0.0009, respectively). Electrocardiogram and neurologic impairment score did not show significant change at 12 months. Measurement of left ventricular mass by MRI and echocardiographic techniques showed significant change in hereditary TTR cardiac amyloidosis within 1 year. In conclusion, these methods provide a means to clinically monitor progression of hereditary TTR amyloidosis and determine efficacy of therapeutic interventions.

Lung nodule computer-aided detection as a second reader: influence on radiology residents.

OBJECTIVE: The purpose of this study was to evaluate the use of a computed tomographic lung nodule computer-aided detection (CAD) software as a second reader for radiology residents. METHODS: The study involved 110 cases from 4 sites. Three expert radiologists identified nodules that were 4 to 30 mm in maximum diameter to form the ground truth. These cases were then interpreted by 6 board-certified radiologists and 6 radiology residents. The residents read each case without and then with a CAD software (Lung Nodule Assesment, Extended Brilliance Workspace; Philips Healthcare, Highlands Heights, OH) to identify nodules that were 4 to 30 mm in maximum diameter. RESULTS: The experts identified 91 nodules as the ground truth for the study. The mean sensitivity of the 6 board-certified radiologists was 89%. The mean sensitivity of the residents was 85% without the CAD and 90% (P < 0.05) with the CAD as a second reader. CONCLUSIONS: The CAD software can help improve the sensitivity of residents in the detection of pulmonary nodules on computed tomography, making them comparable with board-certified radiologists.