Lower attenuation and higher kurtosis of coronary artery calcification associated with vulnerable plaque - an agatston score propensity-matched CT radiomics study.

BACKGROUND: Coronary artery calcification (CAC) burden assessed by Agatston score (AS) is currently recommended to stratify patients at risk for future acute coronary syndrome (ACS). Besides the CAC burden, the biostructure of CAC may also play a vital role in the vulnerability of CAC, which CT radiomics could reveal. Propensity-score matching of the traditional risk factors and CAC burden between the ACS and asymptomatic groups could radically remove biases and allow the exploration of characteristic features of CAC in ACS. METHODS: We retrospectively identified 77 patients with ACS who had a CAC scan before percutaneous coronary intervention between 2016 and 2019. These 77 patients were one-to-two propensity-score matched for traditional risk factors of ACS and AS ranks to select 154 subjects from 2890 asymptomatic subjects. A validation cohort of 30 subjects was also enrolled. Radiomics features of each plaque were extracted and averaged in each person. Conditional logistic regression and area-under-curve analysis were used for statistical analysis. RESULTS: A higher number of coronary segments involved, lower mean, median, first quartile, and standard deviation of attenuation, and increased kurtosis of attenuation of CAC were associated with the ACS group compared to the control group (p < 0.05 for all). Multivariable analysis showed that the lower median attenuation (OR = 0.969, p < 0.001) and higher Kurtosis (OR = 18.7, p < 0.001) were associated with the ACS group. The median attenuation and kurtosis significantly increase across AS ranks 1 to 4 (p = 0.001). The AUC of kurtosis (0.727) and median attenuation (0.66) were both significantly higher than that of the standard AS (AUC = 0.502) and the number of TRF (AUC = 0.537). The best cut-off of kurtosis at 2.74 yielded an accuracy of 74%, and the cut-off of median attenuation at 196 yielded an accuracy of 68%. The accuracy of kurtosis was 64%, and the accuracy of median attenuation was 55% in the validation cohort. CONCLUSION: After propensity-matching traditional risk factors and CAC burden, CT radiomics highlighted that lower median attenuation and higher kurtosis were the CAC characteristics of vulnerable plaques. These features improve the understanding of the biomechanics of CAC evolution and enhance the value of CAC scan in ACS risk assessment.

Recurrent spontaneous massive hemothorax from intrathoracic extramedullary hematopoiesis resulting in respiratory failure.

Extramedullary hematopoiesis (EMH) is a compensatory response to many chronic anemic disorders. Intrathoracic EMH, usually presenting as paravertebral masses over the posterior mediastinum, is a rare entity and is usually asymptomatic. Hemothorax is a rare but possibly fatal complication. Local radiation for intrathoracic EMH is considered effective in preventing its recurrence. Here we describe a patient who had had α-thalassemia for many years and developed a spontaneous left-sided hemothorax from EMH. A chest film and a chest computed tomography (CT) scan had showed multiple paravertebral masses over the lower thoracic spine with left-sided pleural effusion. A pathological diagnosis of EMH was made by video-assisted thoracoscopic surgery. The patient had not received preventive local chest radiation. Ten years later, he suffered from a life-threatening hemothorax complicated by acute respiratory failure without traumatic history. A CT scan showed posterior mediastinal masses over the lower thoracic spine with right-sided pleural effusion. Thoracoscopy was performed to remove the blood clot in the pleural space for successful weaning from mechanical ventilation. This is the first case of intrathoracic EMH to have recurrent hemothorax associated with acute respiratory failure.

The relation of location-specific epicardial adipose tissue thickness and obstructive coronary artery disease: systemic review and meta-analysis of observational studies.

BACKGROUND: There is growing evidence about the importance of epicardial adiposity on cardiometabolic risk. However, the relation of location-specific epicardial adipose tissue (EAT) thickness to coronary atherosclerotic burden is still unclear. METHODS: This meta-analysis was used to study the relations between location-specific EAT thickness and obstructive coronary artery disease (CAD). A systemic literature search to identify eligible studies that met the inclusion criteria from the beginning until January 2014 was made. We conducted the meta-analysis of all included 10 published studies. Pre-specified subgroup analyses were performed according to ethnicity, body mass index, diagnostic tools for CAD, and measurement tool if presence of high heterogeneity between studies. Potential publication bias was also assessed. RESULTS: We identified ten observed studies with a total of 1625 subjects for planned comparison. With regard to the association between obstructive CAD and location-specific EAT thickness at the right ventricular free wall, caution is warranted. The pooled estimate showed that location-specific EAT thickness at the right ventricular free wall was significantly higher in the CAD group than non-CAD group (standardized mean difference (SMD): 0.70 mm, 95% CI: 0.26-1.13, P = 0.002), although heterogeneity was high (I2 = 93%). It should be clear that only the result of echocardiography-based studies showed a significant association (SMD: 0.98 mm, 95% CI: 0.43-1.53, P = 0.0005), and the result of all included CT-based studies showed a non-significant association (SMD: 0.06 mm, 95% CI: -0.12-0.25, P = 0.50). In the subgroup analysis, the "diagnostic tools for CAD" or "measurement tool of EAT thickness" are potential major sources of heterogeneity between studies. With regard to location-specific EAT thickness at the left atrioventricular (AV) groove, it was significantly higher in the CAD group than non-CAD group (SMD: 0.74 mm, 95% CI: 0.55-0.92, P <0.00001; I2 = 0%). CONCLUSION: Our meta-analysis suggests that significantly elevated location-specific EAT thickness at the left AV groove is associated with obstructive CAD. Based on the current evidence, the location-specific EAT thickness at the left AV groove appears to be a good predictor in obstructive CAD, especially in Asian populations. Furthermore well-designed studies are warranted because of the current limited number of studies.

Reliable categorisation of visual scoring of coronary artery calcification on low-dose CT for lung cancer screening: validation with the standard Agatston score.

OBJECTIVES: To validate the reliability of the visual coronary artery calcification score (VCACS) on low-dose CT (LDCT) for concurrent screening of CAC and lung cancer. METHODS: We enrolled 401 subjects receiving LDCT for lung cancer screening and ECG-gated CT for the Agatston score (AS). LDCT was reconstructed with 3- and 5-mm slice thickness (LDCT-3mm and LDCT-5mm respectively) for VCACS to obtain VCACS-3mm and VCACS-5mm respectively. After a training session comprising 32 cases, two observers performed four-scale VCACS (absent, mild, moderate, severe) of 369 data sets independently, the results were compared with four-scale AS (0, 1-100, 101-400, >400). RESULTS: CACs were present in 39.6 % (146/369) of subjects. The sensitivity of VCACS-3mm was higher than for VCACS-5mm (83.6 % versus 74.0 %). The median of AS of the 24 false-negative cases in VCACS-3mm was 2.3 (range 1.1-21.1). The false-negative rate for detecting AS ≥ 10 on LDCT-3mm was 1.9 %. VCACS-3mm had higher concordance with AS than VCACS-5mm (k = 0.813 versus k = 0.685). An extended test of VCACS-3mm for four junior observers showed high inter-observer reliability (intra-class correlation = 0.90) and good concordance with AS (k = 0.662-0.747). CONCLUSIONS: This study validated the reliability of VCACS on LDCT for lung cancer screening and showed that LDCT-3mm was more feasible than LDCT-5mm for CAD risk stratification. KEY POINTS: • Low-dose computed tomography (LDCT) rarely misses significant coronary artery calcification (CAC). • Visual scoring of CAC on LDCT is highly concordant with Agatston scoring. • LDCT-3mm is more feasible than LDCT-5mm for CAD risk stratification. • CAC assessment enriched the screening information for LDCT lung cancer screening.

Inflow-weighted pulmonary perfusion: comparison between dynamic contrast-enhanced MRI versus perfusion scintigraphy in complex pulmonary circulation.

BACKGROUND: Due to the different properties of the contrast agents, the lung perfusion maps as measured by 99mTc-labeled macroaggregated albumin perfusion scintigraphy (PS) are not uncommonly discrepant from those measured by dynamic contrast-enhanced MRI (DCE-MRI) using indicator-dilution analysis in complex pulmonary circulation. Since PS offers the pre-capillary perfusion of the first-pass transit, we hypothesized that an inflow-weighted perfusion model of DCE-MRI could simulate the result by PS. METHODS: 22 patients underwent DCE-MRI at 1.5T and also PS. Relative perfusion contributed by the left lung was calculated by PS (PS(L%)), by DCE-MRI using conventional indicator dilution theory for pulmonary blood volume (PBV(L%)) and pulmonary blood flow (PBFL%) and using our proposed inflow-weighted pulmonary blood volume (PBV(iw)(L%)). For PBViw(L%), the optimal upper bound of the inflow-weighted integration range was determined by correlation coefficient analysis. RESULTS: The time-to-peak of the normal lung parenchyma was the optimal upper bound in the inflow-weighted perfusion model. Using PSL% as a reference, PBV(L%) showed error of 49.24% to -40.37% (intraclass correlation coefficient R(I) = 0.55) and PBF(L%) had error of 34.87% to -27.76% (R(I) = 0.80). With the inflow-weighted model, PBV(iw)(L%) had much less error of 12.28% to -11.20% (R(I) = 0.98) from PS(L%). CONCLUSIONS: The inflow-weighted DCE-MRI provides relative perfusion maps similar to that by PS. The discrepancy between conventional indicator-dilution and inflow-weighted analysis represents a mixed-flow component in which pathological flow such as shunting or collaterals might have participated.

Aortic intramural hematoma with pulmonary artery extension mimics pulmonary embolism.

A 59-year-old woman presented to emergency department with sudden onset of chest tightness and shortness of breath. Laboratory test revealed elevated D-dimer (1558 ng/mL). The electrocardiogram revealed right axis deviation, S1Q3T3 pattern, and T-wave inversion in leads V1 to V6. Computed tomographic angiography (CTA) was performed with 64-slice computed tomography for suspicious of pulmonary embolism. Contrast-enhanced CTA showed no filling defect in the pulmonary arteries; however, luminal narrowing of the right pulmonary artery was noted. Nonenhanced computed tomographic scan showed smooth eccentric high attenuation change along the wall of main pulmonary artery and right pulmonary artery and also along the ascending and descending aorta. The high attenuation lesions in both of the aorta and pulmonary artery showed no contrast enhancement indicating presence of intramural hematoma (IMH). Based on the image findings, a diagnosis of type A aortic IMH with pulmonary artery extension, instead of chronic pulmonary embolism, was made. Follow-up CTA 3 months later showed much improved of the right pulmonary artery narrowing and nearly complete resolution of the IMH.

CT of coronary heart disease: Part 2, Dual-phase MDCT evaluates late symptom recurrence in ST-segment elevation myocardial infarction patients after revascularization.

OBJECTIVE: The purpose of the study was to investigate dual-phase MDCT for assessing obstructive lesions and the extent and severity of the subtending myocardium at risk in patients presenting with chest pain syndromes 9 or more months after having undergone revascularization for the treatment of ST-segment elevation myocardial infarction (STEMI). MATERIALS AND METHODS: Dual-phase 64-MDCT was performed on 135 patients with recurring chest symptoms 9 months or more after revascularization (mean ± SD, 23 ± 11 months after index invasive angiogram for treatment of STEMI). Obstructive lesions (≥ 50% stenosis) were detected by MDCT angiography and the extent of myocardium at risk was detected by delayed phase 3D myocardium maps. A myocardium at-risk score based on MDCT findings was defined as the extent of myocardium at risk governed by the coronary lesion and weighted by lesion severity. Results were compared with stress-redistribution (201)Tl-SPECT and invasive angiography. RESULTS: In restenotic, new, progressive, and previously obstructive lesions that are not currently progressive, analysis of assessable segments (1966/2025, 97.1%) obtained true-positive detection rates of 88.1%, 88.6%, 82.9%, and 100%, respectively; false-negative detection rates were 5.3%, 1.6%, 2.9%, and 8.8%. In 124 patients (91.9%) in whom all segments were assessable, the MDCT-based myocardium at-risk score correlated with the SPECT-based summed difference score (SDS) (r = 0.841, p < 0.001). For detecting SPECT-based SDS ≥ 1 and SDS > 3, areas under the receiver operating characteristic curve for the MDCT-based myocardium at-risk score were 0.874 (95% CI, 0.805-0.942) and 0.938 (95% CI, 0.895-0.981), with optimal cutoff values of 2.68 and 5.01, respectively. CONCLUSION: Dual-phase MDCT is useful in detecting different patterns of obstructive lesions and the extent of myocardium at risk as an alternative for therapeutic planning in patients presenting with late symptoms after treatment for acute myocardial infarction.

Intramural blood pools accompanying aortic intramural hematoma: CT appearance and natural course.

PURPOSE: To evaluate multidetector computed tomographic (CT) images to investigate the prevalence, morphology, natural course, and prognostic effect of intramural blood pools (IBPs) in patients with acute intramural hematoma (IMH). MATERIALS AND METHODS: Institutional review board approval and written informed consent were obtained. Sixty-five patients (41 men; mean age, 65.9 years ± 11.3 [standard deviation]) with acute IMH undergoing three or more multidetector CT examinations during follow-up for 12 months or longer (median = 18 months), except for those undergoing surgery (n = 16), were enrolled. Associated factors of developing and resorption of IBP in IMH were analyzed by using logistic regression. RESULTS: There were 40 IBPs in 10 patients at initial multidetector CT, and 15 new IBPs developed in 11 patients during follow-up. IBPs occurred most in the descending thoracic (55% [31 of 56]) and abdominal (41% [23 of 56]) aorta in 28% (18 of 65) of patients. During 33.8 months (range, 2.8-50 months) of follow-up in these 18 patients, 57% (32 of 56) of IBPs showed complete resorption in 15 patients, 29% (16 of 56) of IBPs showed incomplete resorption in eight patients, and 14% (eight of 56) of IBPs had interrupted follow-up because of surgery or death in three patients. Logistic regression showed that age younger than 70 years (odds ratio [OR], 8.74; 95% confidence interval [CI]: 1.03, 76.9) and IMH wall thickness greater than 10 mm (OR, 4.93; 95% CI: 1.04, 23.0) were associated with developing IBP at initial multidetector CT, while IBP with larger transmural diameter (OR, 1.16; 95% CI: 1.02, 1.31) and multidetector CT-demonstrated connection with intercostal or lumbar artery (63% [35 of 56]) (OR, 5.44; 95% CI: 1.43, 20.9) were associated with incomplete resorption. CONCLUSION: IBPs are frequently observed at multidetector CT in patients with IMH. They may resolve over time or appear during follow-up. These findings are not associated with a poor prognosis, and IBPs should be distinguished from ulcerlike projections.

Identifying predictors for bacterial and fungal coinfection on chest computed tomography in patients with Pneumocystis pneumonia.

BACKGROUND: Pneumocystis pneumonia (PCP) is a common opportunistic infection with high mortality in individuals with decreased immunity. Pulmonary coinfections with PCP are associated with poor prognosis. The study aims to identify radiological predictors for pulmonary coinfections in patients with PCP and risk factors for mortality. METHODS: This is a retrospective, five-year study was conducted in a medical center, enrolling patients diagnosed with PCP, who received a chest computed tomography (CT) scan. The radiological findings and medical records of all participants were reviewed carefully by 2 independent doctors. Univariable and multivariable analysis was performed to identify radiological predictors for pulmonary coinfection and clinical risk factors for poor prognosis. RESULTS: A total of 101 participants were included, of which 39 were HIV-infected and 62 were non-HIV-infected. In multivariable analysis, radiologic predictors on chest CT for coinfection with bacteria pneumonia included lack of ground glass opacity (adjusted odds ratio [aOR], 6.33; 95% confidence interval [CI], 2.03-19.77; p = 0.001) and presence of pleural effusion (aOR, 3.74; 95% CI, 1.27-10.99; p = 0.017). Predictors for fungal pneumonia included diffuse consolidation (adjusted OR, 6.27; 95% CI, 1.72-22.86; p = 0.005) and presence of pleural effusion (adjusted OR, 5.26; 95% CI, 1.44-19.17; p = 0.012). A significantly higher in-hospital mortality was associated with older age, recent corticosteroid exposure, cytomegalovirus coinfection, and acute respiratory failure. CONCLUSION: Early identification of pulmonary coinfections in PCP using radiological features on the CT scans, will enable appropriate treatment which is crucial to improve the prognosis.

Prognostic effect of implementation of the mass low-dose computed tomography lung cancer screening program: a hospital-based cohort study.

Low-dose computed tomography lung cancer screening aims to detect early-stage lung cancers in order to decrease the incidence of advanced-stage lung cancers and to reduce lung cancer mortality. We analyzed the time trends of lung cancer stage distribution and mortality rates after the gradual implementation of the low-dose computed tomography lung cancer screening in a hospital-based cohort. Using the hospital-based cancer registry data on lung cancer number and death from 2007 to 2014, we aim to evaluate the trends in stage distribution and mortality rate after the gradual implementation of low-dose computed tomography lung cancer screening program over recent years. From 2007 to 2014, overall 2542 cases of lung cancers were diagnosed according to hospital-based cancer registry. For the 1-year mortality rate, the mortality rate decreased gradually from 48.16 to 37.04% between 2007 and 2014. For the 5-year mortality rate, the mortality rate decreased gradually from 88.49 to 69.44% between 2007 and 2014. There was a gradual decrease in stage IV lung cancer with the corresponding sharp increase in stage I early lung cancer after following the implementation of the large volume of the low-dose computed tomography examination between the years 2011 and 2014. In conclusion, these results suggest that the gradual implementation of low-dose computed tomography lung screening program could lead to a remarkable decrease in lung cancer mortality and a remarkable stage shift in the trend over time in this hospital-based cohort.

Percutaneous retrieval of dislodged central venous port catheter: experience of 25 patients in a single institute.

BACKGROUND: For a dislodged port catheter, percutaneous retrieval by using a loop snare or a basket is the standard technique, with high success. However, once a loop snare fails, the likelihood of success with other tools is considered low. PURPOSE: To report our experience of percutaneous retrieval of dislodged port catheters and to emphasize the usefulness of grasping forceps. MATERIAL AND METHODS: During a 6-year period, a total of 25 dislodged port catheters were retrieved in our institute. The interval between port catheter implantation and dislodged catheter retrieval was 3-85 months (mean 23 months). The time of delayed retrieval ranged from 3 to 604 days (mean 58 days). A loop snare or grasping forceps were used via either the femoral or jugular route. RESULTS: The prevalence of port catheter dislodgement was 0.4% in our institute. All dislodged port catheters were successfully removed, including four patients with delayed retrieval of more than 90 days. A loop snare was used in 20 patients, with technical success in 18. Grasping forceps were used in seven patients, all with success (including the two patients who failed by initial use of a loop snare). No procedure-related complications were encountered, except transient arrhythmia in four patients requiring no medication. CONCLUSION: Although the prevalence of port catheter dislodgement is low, percutaneous attempts at retrieval should be performed in all patients, even in chronic settings. A loop snare is the instrument of choice for retrieval. Grasping forceps can be used as an auxiliary instrument, especially in patients where a loop snare fails.

Diagnostic performance of MR imaging in the assessment of subchondral fractures in avascular necrosis of the femoral head.

OBJECTIVE: A prospective study was conducted to determine the accuracy of routine magnetic resonance (MR) imaging in correctly identifying subchondral fracture in avascular necrosis of the femoral head without apparent focal collapse on standard radiographs. MATERIALS AND METHODS: Spiral computed tomography (CT) with coronal and sagittal reformations and routine MR imaging with spin-echo T1WI and fat-suppressed spin-echo T2WI coronal, axial, and sagittal images were performed in 28 hips of 25 patients (M/F = 20:5; age 16-76 years) suffering from early-stage avascular necrosis of the femoral head on standard radiographs. The MR images were reviewed by a musculoskeletal radiologist and a general radiologist in blinded fashion. Using CT as the standard of reference, the accuracy of MR imaging in diagnosing subchondral fractures in avascular necrosis was evaluated. RESULTS: When the diagnoses of the two readers were compared with each other, only 16 of the 28 diagnoses (57.5%) agreed. Seventeen of the 28 MR imaging readings (60.7%) made by the musculoskeletal radiologist and 15 of the 28 (53.5%) made by the general radiologist agreed with those of the CT standard. False-positive diagnosis (that is, diagnosis of fracture when no fracture could be seen on CT) was more common than false-negative diagnosis. CONCLUSIONS: The accuracy of routine MR imaging in the evaluation of subchondral fracture is not satisfactory. False-positive diagnosis is not uncommon. Interpretation of routine MR imaging readout should be guarded.

Differences in lung cancer characteristics and mortality rate between screened and non-screened cohorts.

Screening programs for lung cancer aim to allow diagnosis at the early stage, and therefore the decline in mortality rates. Thus, the aim of this retrospective cohort study was to the comparison of screened and non-screened lung cancer in terms of lung cancer characteristics, overdiagnosis and survival rate. A retrospective study in which 2883 patients with 2883 lung cancer diagnosed according to the hospital-based lung cancer register database between 2007 and 2017. A comparison was performed in term of clinical characteristics and outcomes of lung cancer between the screened and non-screening patient groups. 2883 subjects were identified (93 screened and 2790 non-screened). Screened group patients were younger (59.91 ± 8.14 versus 67.58 ± 12.95; p < 0.0001), and were more likely to be female than non-screened group (61.3% versus 36.8%; p < 0.0001). The screened group showed significantly better outcomes in overall mortality than the non-screened group (10.75% versus 79.06%; <0.0001). In a Cox proportional hazard model, lung cancer in the screened group proved to be an independent prognostic factor in lung cancer subjects. Our findings point to the improved survival outcome in the screened group and might underline the benefit of low-dose computed tomography (LDCT) screening program in Asian populations with the high prevalence of non-smoking-related lung cancer. Further study aimed at the LDCT mass screening program targeting at light smokers and non-smoker outside of existing screening criteria is warranted.

Identification and viability assessment of infarcted myocardium with late enhancement multidetector computed tomography: comparison with thallium single photon emission computed tomography and echocardiography.

BACKGROUND: Recent studies revealed that multidetector computed tomography late enhancement (MDCT-LE) is a reliable technique for detecting necrotic and scarred myocardial tissue. The aims of the study were to identify infarcted myocardium using MDCT-LE protocol in patients after myocardial infarction (MI) and assess viability in resting wall motion abnormalities. METHODS: One hundred one patients with previous MI (62 +/- 13 years, 1-6 months after MI) underwent MDCT-LE (15 minutes after contrast medium administration), rest-redistribution thallium single photon emission computed tomography (Tl-SPECT), and dobutamine echocardiography (DbE). In a 17-segment model, infarcted myocardium detected by MDCT-LE was categorized as none, 1%-25%, 26%-50%, 51%-75%, or >75% segmental extent and was compared with decreased uptake of Tl-SPECT and contractile function by DbE on per patient and segmental basis in a blinded fashion. RESULTS: By per patient analysis, MDCT-LE identified the presence of infarcted myocardium in 97 patients (96%), and Tl-SPECT decreased uptake in 88 patients (87%), (P = .02). By per segment analysis, the concordance for detecting infarcted myocardium was good (kappa value = 0.792). In segments with resting wall motion abnormalities (N = 486), there was moderate concordance in assessing viability (kappa value between MDCT and Tl-SPECT = 0.555, MDCT and DbE = 0.498, Tl-SPECT and DbE = 0.478) with predefined MDCT-LE threshold of 50% segmental extent. Among segments with MDCT-LE >75% segmental extent, the proportion designated nonviable by Tl-SPECT and DbE reached 87.8% and 92.2%, respectively. CONCLUSIONS: Multidetector computed tomography late enhancement is accurate in identifying the presence and extent of infarcted myocardium. Its segmental extent has good correlation with the magnitude of thallium decreased uptake and can predict contractile reserve. Multidetector computed tomography late enhancement can be an alternative to assess viability.

Coronary arterial calcification on low-dose ungated MDCT for lung cancer screening: concordance study with dedicated cardiac CT.

OBJECTIVE: Coronary artery calcification (CAC) is frequently detected on low-dose ungated MDCT performed for lung cancer screening. We aimed to determine the concordance of CAC scores on low-dose ungated and regular-dose ECG-gated MDCT. SUBJECTS AND METHODS: The subjects were 513 patients consecutively registered for health screening and undergoing both low-dose ungated (120 kVp, 20 mAs) and regular-dose ECG-gated MDCT (120 kVp, 150 mAs, retrospective ECG gating). The first 30 cases were used for protocol optimization and a training session. Agatston score on regular-dose ECG-gated and low-dose ungated MDCT in the other 483 cases (320 men; mean age, 62.2 +/- 13.2 [SD] years) was calculated by two observers in a blinded manner. Interobserver and intertechnique scoring variability and concordance were calculated. RESULTS: The mean of interobserver scoring variability for regular-dose ECG-gated MDCT was 3.6% and for low-dose ungated MDCT was 9.6%. Regular-dose ECG-gated MDCT depicted CAC in 221 (46%) of the subjects. With low-dose ungated MDCT, observers 1 and 2, respectively, had five and seven false-positive and five and four false-negative predictions. All the miscategorized scores were 12 or less. The negative predictive values of CAC on low-dose ungated MDCT were 98% and 99% for observers 1 and 2, respectively. For patients with CAC, the mean intertechnique scoring variability was 40-43%. For all 483 subjects, the intertechnique concordance of the four major score ranks (0, 1-100, 101-400, > 400) was high (kappa = 0.89 for the two observers). CONCLUSION: Low-dose ungated MDCT with an optimized protocol is reliable for prediction of the presence of CAC and categorization of the four major Agatston score ranks. This technique may be useful for coronary artery disease risk stratification of persons undergoing low-dose ungated MDCT for lung cancer screening.

Renal artery involvement in acute aortic dissection: Prevalence and impact on renal atrophy in non-interventional treatment patients.

BACKGROUND: To evaluate the frequency of renal artery dissection (RAD) and renal hypoperfusion in aortic dissection (AD) and its effect on subsequent renal atrophy in patients who did not undergo therapeutic intervention. METHODS: Initial CT data of 155 patients with acute AD (Stanford type A = 88, B = 67) were retrospectively analyzed. The false lumen statuses were patent (n = 94), partially thrombosed (n = 25), and completely thrombosed (n = 36) (also called as intramural hematoma (IMH)). Follow-up CT images of the surviving 122 patients (6-62.6 months, median, 28.9 months) were reviewed for analysis of sequential changes in renal volume. A regional decrease of ≧20 Hounsfield units in the renal cortex was defined as a renal hypo-enhancement sign (RHS). Simplified CT estimations of renal volume and estimated glomerular filtration rates (eGFR) were calculated. The generalized estimating equations (GEE) method was used to predict renal atrophy. RESULTS: Fifty of the 122 patients presented with 59 RAD in the current study, and a positive RHS was noted in 33.9% (20/59) of these involved kidneys. GEE analysis showed hypertension, surgical treatment for AD, presence of RAD, and positive RHS as significant risk factors for renal atrophy. Patients with RHS had the most severe form of renal atrophy. The severity of renal atrophy was mildly correlated with GFR change (γ2 = 0.044, p < 0.001). CONCLUSION: Renal atrophy in AD was predicted by the CT findings of RAD and RHS. The severity of renal atrophy was weakly reflected by eGFR.

Modified Lung-RADS Improves Performance of Screening LDCT in a Population with High Prevalence of Non-smoking-related Lung Cancer.

OBJECTIVES: We proposed a modification of the ACR Lung Imaging Reporting and Data System (Lung-RADS) to clarify the characteristics of subsolid nodules with categories 1-11, and to compare the diagnostic accuracy with Lung-RADS and National Lung Screening Trial criteria in an Asian population with high prevalence of adenocarcinoma. METHODS: We analyzed a retrospective cohort of 1978 consecutive healthy subjects (72.8% nonsmoker) who underwent low-dose computed tomography from August 2013 to October 2014 (1084 men, 894 women). Lung-RADS categories 2 and 3 were modified to include subcategories of 2A/2B/2C and 3A/3B/3C, respectively. Clinical information and nodule characteristics were recorded. Receiver operating characteristic curves were used to compare diagnostic accuracy at different cutoffs. RESULTS: Thirty-two subjects (30 nonsmokers) had pathology-proven adenocarcinoma spectrum lesions in the follow-up period (1.6 ± 0.5 years). Modified Lung-RADS, using modified Lung-RADS category 2C as cutoff, had an area under the curve (AUC) of 0.973 in predicting adenocarcinoma spectrum lesions (sensitivity of 100%, specificity of 89.3%), which was significantly higher than that of Lung-RADS (AUC = 0.815, P < .001) and National Lung Screening Trial (AUC = 0.906, P < .001). Furthermore, modified Lung-RADS showed an AUC of 0.992 in predicting invasive adenocarcinoma (sensitivity of 95%, specificity of 97.8%) when category 3B was used as cutoff. CONCLUSIONS: Modified Lung-RADS may substantially improve sensitivity while maintaining specificity for detection of adenocarcinoma spectrum lesions in an Asian population. Compared to Lung-RADS, it has enhanced ability to differentiate invasive from indolent adenocarcinoma by more refined subclassification of subsolid nodules using two cutoff values of category 2C and 3B. The effect of using modified Lung-RADS in clinical practice must be carefully studied in prospective large cohort studies.