Radiation dose and image quality of computed tomography of the supra-aortic arteries: A comparison between single-source and dual-source CT Scanners.

PURPOSE: The purpose of this work was to compare the image quality and radiation dose delivered to patients during computed tomography (CT) angiography (CTA) of the supra-aortic arteries using two single-source (SS) and two dual-energy (DE) CT scanners. MATERIAL AND METHODS: In this retrospective study, 120 patients who underwent CTA of supra-aortic arteries were studied using four different types of CT scanners: a sixteen and forty-detector-row SS and two DE CT scanners. Seventy milliters of contrast medium were injected at a flow rate of 4mL/s using a power injector. For each patient the dose-length product (DLP), the volume computed tomography dose index (CDTIvol), the length of the scan and the effective dose (ED) were calculated. Qualitative and quantitative [image noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR)] image quality assessment was performed. RESULTS: A statistically significant lower value of the DE compared to the SS technology (P<0.0001) for the CDTI, DLP and ED was found, whereas we did not find any statistically significant difference between the four scanners for the measurements of the image noise, SNR and CNR. CONCLUSION: DS CT scanners allow performing CTAs with a reduced dose compared to SS CT scanner with comparable image quality.

Relationship between Carotid Computed Tomography Dual-Energy and Brain Leukoaraiosis.

BACKGROUND: The purpose of this study was to assess if there is a correlation between the carotid computed tomography (CT) Hounsfield unit (HU)-based plaque attenuation values measured using dual-energy CT (DECT) scanner and brain leukoaraiosis (LA). METHODS: Fifty consecutive patients (34 males, 16 females; mean age, 69 years; age range, 46-84 years) who underwent carotid CT and brain magnetic resonance imaging were included in the study. CT examinations were performed with a DECT scanner, and LA lesion volume quantification was performed using a semiautomated segmentation technique. RESULTS: We found an inverse statistically significant correlation between the HU-based carotid artery plaque attenuation and the LA lesion volume. Because of the presence of calcified plaques, a second model was calculated at low kiloelectron volt levels from 66 to 100 and 100 kV by taking into consideration the fatty and mixed plaques, and this further led to the associations between HU-based attenuation and LA volume in brain and vascular territories. CONCLUSIONS: The results of our study suggest that the associations between HU attenuation of the carotid artery plaques (with the exclusion of calcified plaques) and the volume of LA are emphasized at low keV energy levels.

Relationship between leukoaraiosis, carotid intima-media thickness and intima-media thickness variability: Preliminary results.

OBJECTIVE: To assess the relationship between the degree of leukoaraiosis (LA), carotid intima-media thickness (IMT) and intima-media thickness variability (IMTV). MATERIALS AND METHODS: Sixty-one consecutive patients, who underwent a brain MRI examination and a carotid artery ultrasound, were included in this retrospective study, which conformed with the Declaration of Helsinki. Written informed consent was waived. In each patient, right/left carotid arteries and brain hemispheres were assessed using automated software for IMT, IMTV and LA volume. RESULTS: The mean hemispheric LA volume was 2,224 mm3 (SD 2,702 mm3) and there was no statistically significant difference in LA volume between the right and left hemispheres (p value = 0.628). The mean IMT and IMTV values were 0.866 mm (SD 0.170) and 0.143 mm (SD 0.100), respectively, without significant differences between the right and left sides (p values 0.733 and 0.098, respectively). The correlation coefficient between IMTV and LA volume was 0.41 (p value = 0.0001), and 0.246 (p value = 0.074) between IMT and LA volume. CONCLUSIONS: IMTV significantly correlates with LA volume. Further studies are warranted to verify whether this parameter can be used clinically as a marker of cerebrovascular risk. KEY POINTS: • Intima-media thickness variability (IMTV) significantly correlates with leukoaraiosis volume. • IMTV could be used as a marker for cerebrovascular risk. • IMTV seems to be a better predictor of weighted mean difference than IMT.

Longitudinal assessment of carotid atherosclerosis after Radiation Therapy using Computed Tomography: A case control Study.

OBJECTIVES: To study the carotid artery plaque composition and its volume changes in a group of patients at baseline and 2 years after head and neck radiation therapy treatment (HNXRT). METHODS: In this retrospective study, 62 patients (41 males; mean age 63 years; range 52-81) who underwent HNXRT and 40 patients (24 males; mean age 65) who underwent surgical resection of neoplasm and did not undergo HNXRT were assessed, with 2-year follow-up. The carotid artery plaque volumes, as well as the volume of the sub-components (fatty-mixed-calcified), were semiautomatically quantified. Mann-Whitney and Wilcoxon tests were used to test the hypothesis. RESULTS: In the HNXRT group, there was a statistically significant increase in the total volume of the carotid artery plaques (from 533 to 746 mm(3); p = 0.001), in the fatty plaques (103 vs. 202 mm(3); p = 0.001) and mixed plaque component volume (328 vs. 419 mm(3); p = 0.034). A statistically significant variation (from 21.8 % to 27.6 %) in the percentage of the fatty tissue was found. CONCLUSIONS: Results of this preliminary study suggest that HNXRT promotes increased carotid artery plaque volume, particularly the fatty plaque component. KEY POINTS: HNXRT increases carotid plaque volume. Plaque volume increase is mainly due to increase.in fatty plaque component. Patients who undergo HNXRT have a progression of carotid artery disease.

Association between internal carotid artery dissection and arterial tortuosity.

INTRODUCTION: Carotid artery dissection is an important cause of ischemic stroke in all age groups, particularly in young patients. The purpose of this work was to assess whether there is an association between the presence of an internal carotid artery dissection (ICAD) and the arterial tortuosity. METHODS: This study considered 124 patients (72 males and 52 females; median age 57 years) with CT/MR diagnosis of ICAD of the internal carotid artery were considered in this multi-centric retrospective study. The arterial tortuosity was evaluated and, when present, was categorized as elongation, kinking, or coiling. For each patient, both the right and left sides were considered for a total number of 248 arteries in order to have the same number of cases and controls. Fisher's exact test was applied to test the association between elongation, kinking, coiling, dissection, and the side affected by CAD. RESULTS: Fisher's exact test showed a statistically significant association between the ICAD and kinking (p = 0.0089) and coiling (p = 0.0251) whereas no statistically significant difference was found with arterial vessel elongation (p = 0.444). ICAD was more often seen on the left side compared to the right (p = 0.0001). These results were confirmed using both carotid arteries of the same patient as dependent parameter with p = 0.0012, 0.0129, and 0.3323 for kinking, coiling, and elongation, respectively. CONCLUSION: The presence of kinking and coiling is associated with ICAD.

Italian Registry of Cardiac Computed Tomography.

PURPOSE: Cardiac CT (CCT) is an imaging modality that is becoming a standard in clinical cardiology. We evaluated indications, safety, and impact on patient management of routine CCT in a multicenter national registry. MATERIALS AND METHODS: During a period of 6 months, 47 centers in Italy enrolled 3,455 patients. RESULTS: CCT was performed mainly with 64-slice CT scanners (73.02 %). Contrast agents were administrated in 3,185 patients (92.5 %). Mean DLP changes with type of scanner and was lower in >64 row detector scanner. The most frequent indication for CCT was suspected CAD (44.8 %), followed by calcium scoring (9.6 %), post-angioplasty/stenting (8.3 %), post-CABGs (7.5 %), study of cardiac anatomy (4.22 %) and assessment in patients with known CAD (4.1 %) and acute chest pain (1.99 %). Most of the CCTs were performed in outpatient settings (2,549; 74 %) and a minority in inpatient settings (719, 20.8 %). Adverse clinical events (mild-moderate) occurred in 26 examinations (0.75 %). None of them was severe. In 45.3 % of the cases CCT findings impacted patient management. CONCLUSION: CCT is performed with different workloads in participating centers. It is a safe procedure and its results have a strong impact on patient management.

Advanced imaging and Crohn's disease: An overview of clinical application and the added value of artificial intelligence.

PURPOSE: The purpose of this narrative review is to describe the clinical applications of advanced computed tomography (CT) and magnetic resonance (MRI) techniques in patients affected by Crohn's disease (CD), giving insights about the added value of artificial intelligence (AI) in this field. METHODS: We performed a literature search comparing standardized and advanced imaging techniques for CD diagnosis. Cross-sectional imaging is essential for the identification of lesions, the assessment of active or relapsing disease and the evaluation of complications. RESULTS: The studies reviewed show that new advanced imaging techniques and new MRI sequences could be integrated into standard protocols, to achieve a reliable quantification of CD activity, improve the lesions' characterization and the evaluation of therapy response. These promising tools are: dual-energy CT (DECT) post-processing techniques, diffusion-weighted MRI (DWI-MRI), dynamic contrast-enhanced MRI (DCE-MRI), Magnetization Transfer MRI (MT-MRI) and CINE-MRI. Furthermore, AI solutions show a potential when applied to radiological techniques in these patients. Machine learning (ML) algorithms and radiomic features prove to be useful in improving the diagnostic accuracy of clinicians and in attempting a personalized medicine approach, stratifying patients by predicting their prognosis. CONCLUSIONS: Advanced imaging is crucial in the diagnosis, lesions' characterisation and in the estimation of the abdominal involvement in CD. New AI developments are promising tools that could support doctors in the management of CD affected patients.

Clinical neuroimaging markers of response to treatment in mood disorders.

Mood disorders (MD) are important and frequent psychiatric illness. The management of patients affected by these conditions represents an important factor of disability as well as a significant social and economic burden. The "in-vivo" studies can help researchers to understand the first developmental events of the pathology and to identify the molecular and non-molecular targets of therapies. However, they have strong limitations due to the fact that human brain circuitry can not be reproduced in animal models. In addition, these neural pathways are difficult to be selectively studied with the modern imaging (such as Magnetic Resonance and Positron Emitted Tomography/Computed Tomography) and non-imaging (such as electroencephalography, magnetoencephalography, transcranial magnetic stimulation and evoked potentials) methods. In comparison with other methods, the "in-vivo" imaging investigations have higher temporal and spatial resolution compared to the "in-vivo" non-imaging techniques. All these factors make difficult to fully understand the aetiology and pathophysiology of these disorders, and consequently hinder the analysis of the effects of pharmacological and non-pharmacological therapies, which have been demonstrated effective in clinical settings. In this review, we will focus our attention on the current state of the art of imaging in the assessment of treatment efficacy in MD. We will analyse briefly the actual classification of MD; then we will focus on the "in vivo" imaging methods used in research and clinical activity, the current knowledge about the neural models at the base of MD. Finally the last part of the review will focus on the analysis of the main markers of response to treatment.

Carotid artery dissection on non-contrast CT: does color improve the diagnostic confidence?

PURPOSE: The purpose of this work was to evaluate if the use of color maps, instead of conventional grayscale images, would improve the observer's diagnostic confidence in the non-contrast CT evaluation of internal carotid artery dissection (ICAD). MATERIALS AND METHODS: One hundred patients (61 men, 39 women; mean age, 51 years; range, 25-78 years), 40 with and 60 without ICAD, underwent non-contrast CT and were included in this the retrospective study. In this study, three groups of patients were considered: patients with MR confirmation of ICAD, n=40; patients with MR confirmation of ICAD absence, n=20; patients who underwent CT of the carotid arteries because of atherosclerotic disease, n=40. Four blinded observers with different levels of expertise (expert, intermediate A, intermediate B and trainee) analyzed the non-contrast CT datasets using a cross model (one case grayscale and the following case using the color scale). The presence of ICAD was scored on a 5-point scale in order to assess the observer's diagnostic confidence. After 3 months the four observers evaluated the same datasets by using the same cross-model for the alternate readings (one case color scale and the following case using the grayscale). Statistical analysis included receiver operating characteristics (ROC) curve analysis, the Cohen weighted test and sensitivity, specificity, PPV, NPV, accuracy, LR+ and LR-. RESULTS: The ROC curve analysis showed that, for all observers, the use of color scale resulted in an improved diagnostic confidence with AUC values increasing from 0.896 to 0.936, 0.823 to 0.849, 0.84 to 0.909 and 0.749 to 0.861 for expert, intermediate A, intermediate B and trainee observers, respectively. The increase in diagnostic confidence (between the AUC areas) was statistically significant (p=0.036) for the trainee. Accuracy as well as sensitivity, specificity, PPV, NPV, LR+ and LR- were improved using the color scale. CONCLUSION: Our study suggests that the use of a color scale instead the conventional grayscale improves the diagnostic confidence, accuracy and inter-observer agreement of the readers, in particular of junior ones, in the diagnosis of ICAD on non-contrast CT.