Comparative assessment of image quality for coronary CT angiography with iobitridol and two contrast agents with higher iodine concentrations: iopromide and iomeprol. A multicentre randomized double-blind trial.

OBJECTIVES: To demonstrate non-inferiority of iobitridol 350 for coronary CT angiography (CTA) compared to higher iodine content contrast media regarding rate of patients evaluable for the presence of coronary artery stenoses. METHODS: In this multicentre trial, 452 patients were randomized to receive iobitridol 350, iopromide 370 or iomeprol 400 and underwent coronary CTA using CT systems with 64-detector rows or more. Two core lab readers assessed 18 coronary segments per patient regarding image quality (score 0 = non diagnostic to 4 = excellent quality), vascular attenuation, signal and contrast to noise ratio (SNR, CNR). Patients were considered evaluable if no segment had a score of 0. RESULTS: Per-patient, the rate of fully evaluable CT scans was 92.1, 95.4 and 94.6 % for iobitridol, iopromide and iomeprol, respectively. Non-inferiority of iobitridol over the best comparator was demonstrated with a 95 % CI of the difference of [-8.8 to 2.1], with a pre-specified non-inferiority margin of -10 %. Although average attenuation increased with higher iodine concentrations, average SNR and CNR did not differ between groups. CONCLUSIONS: With current CT technology, iobitridol 350 mg iodine/ml is not inferior to contrast media with higher iodine concentrations in terms of image quality for coronary stenosis assessment. KEY POINTS: • Iodine concentration is an important parameter for image quality in coronary CTA. • Contrast enhancement must be balanced against the amount of iodine injected. • Iobitridol 350 is non-inferior compared to CM with higher iodine concentrations. • Higher attenuation with higher iodine concentrations, but no SNR or CNR differences.

LEPTOSPIROSIS AND LIVER ABSCESS: AN UNUSUAL ASSOCIATION.

Leptospirosis is a zoonotic infection infrequently reported in non-tropical regions. Although classically described as a biphasic illness, unusual clinical manifestations have been reported, including a previous case of a lung abscess associated with this causative agent. We present the case of a 49-year-old man with a new diagnosis of two liver abscesses associated with leptospirosis. LEARNING POINTS: Leptospirosis is a zoonosis caused by spirochetes of the genus Leptospira; the infection is more commonly reported in tropical regions.Leptospirosis classically manifests as a biphasic illness, the first phase characterized by high fever that coincides with leptospiraemia, followed by a brief period when the patient is afebrile. In the second phase, fever returns, accompanied by jaundice and renal failure.The unusual clinical manifestations of leptospirosis include a previous report of a lung abscess, but despite frequent liver involvement, liver abscess in this context has not previously been described.

British Thoracic Society Quality Standard for Clinically Significant Bronchiectasis in Adults 2022.

This British Thoracic Society Quality Standard for Clinically Significant Bronchiectasis in Adults 2022 aims to encourage good practice by setting standards of high-quality respiratory care that services should follow.

The clinical efficacy of low-dose whole-lung irradiation in moderate-to-severe COVID-19 pneumonia: RTMX-20 trial.

This is a paired prospective comparative cohort study with 58 patients, in order to analyze the clinical LD-WLI in patients with moderate or severe COVID19 pneumonia. The results of this study show that the Radiotherapy could be an option to improve the clinical response for patients with COVID-19.

Inflammatory Bowel Disease in Migrant Populations: Should we Look Even Further Back?

BACKGROUND: The incidence of inflammatory bowel disease (IBD) continues to rise worldwide. Despite the advances in pharmacotherapy, the etiopathogenesis of Crohn's disease (CD) and ulcerative colitis (UC) remains underexplained. The migratory waves are a challenging setting to analyze the evolution of IBD prevalence and to infer its triggering factors. OBJECTIVE: Our study aimed to overview the literature regarding IBD prevalence and phenotype in first- and second-generation migrants Also, we aimed to summarize the migration history and to draw a possible correlation with IBD distribution. METHODS: A non-systematic review was performed following electronic (PubMed and Web of Science) and manual searches on relevant topics. RESULTS: Overall, first-generation migrants tend to maintain the IBD risk of the native country. On the following generation, the risk tends to converge to that of the destination country. Earlier age at migration modulates IBD risk, suggesting that the degree of exposure to environmental and socio-economic factors can be decisive for disease progression. In general, CD needs more time to reach a disease burden similar to that of the host country, indicating that UC may be more affected by nongenetic factors and genetic-nongenetic interactions. CONCLUSION: IBD phenotypes and natural history vary in migrants and according to ethnicity; however, the trends are not consensual among cohorts. Further studies are warranted to analyze the effect of genetic background and environmental risk factors in different ethnic groups, providing evidence to move towards the identification of at-risk individuals, prevention, and earlier diagnosis of IBD.

Withdrawal Notice: Inflammatory Bowel Disease in migrant populations - a narrative review

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Accuracy of right ventricular volume and function assessed with cardiovascular magnetic resonance: comparison with echocardiographic parameters.

BACKGROUND: Cardiac magnetic resonance imaging (MRI) is an essential imaging method used to assess patients with diseases of the left and right ventricles. Cardiac MRI is the gold standard for right ventricular measurements; however, the most suitable method for volumetric analysis of the right ventricle remains controversial. AIMS: To compare the accuracy of the short axis and four-chamber view segmentation methods in assessing the right ventricle in cardiac MRI studies, to determine the reproducibility of cardiac MR measurements, and to correlate cardiac MR methods with frequently used echocardiographic methods. METHODS: Eighty patients with different clinical indications were studied using a 1.5-Tesla resonance magnetic unit. In all patients, the end-diastolic volume, end-systolic volume, and right ventricle ejection fraction were measured in the short axis and four-chamber views. Twenty-three patients also underwent echocardiography on the same day the cardiac MRI was completed. RESULTS: Cardiac MRI revealed no statistically significant differences in the volume or function of the right ventricle, calculated by the two segmentation methods (p > 0.05). The correlation was excellent between both planes in the assessment of the volume (concordance correlation coefficient [CCC] = 0.97) and the ejection fraction (CCC = 0.90). The correlation was low between the right ventricular ejection fraction and the echocardiographic methods (CCC = 0.02 and CCC = 0.01). CONCLUSION: Right ventricular function in normal ventricles and in dilated ventricles was appropriately measured by cardiac MRI using either of the two segmentation methods. Both methods were highly accurate. However, the correlation with echocardiographic methods was rather poor.

Computerized detection of breast masses in digitized mammograms.

We propose a system to detect malignant masses on mammograms. We investigated the behavior of an iris filter at different scales. After iris filter was applied, suspicious regions were segmented by means of an adaptive threshold. Suspected regions were characterized with features based on the iris filter output and, gray level, texture, contour-related, and morphological features extracted from the image. A backpropagation neural network classifier was trained to reduce the number of false positives. The system was developed and evaluated with two completely independent data sets. Results for a test set of 66 malignant and 49 normal cases, evaluated with free-response receiver operating characteristic analysis, yielded a sensitivity of 88% and 94% at 1.02 false positives per image for lesion-based and case-based evaluation, respectively. Results suggest that the proposed method could help radiologists as a second reader in mammographic screening.

Integrating CAD modules in a PACS environment using a wide computing infrastructure.

PURPOSE: The aim of this paper is to describe a project designed to achieve a total integration of different CAD algorithms into the PACS environment by using a wide computing infrastructure. METHODS: The aim is to build a system for the entire region of Galicia, Spain, to make CAD accessible to multiple hospitals by employing different PACSs and clinical workstations. The new CAD model seeks to connect different devices (CAD systems, acquisition modalities, workstations and PACS) by means of networking based on a platform that will offer different CAD services. This paper describes some aspects related to the health services of the region where the project was developed, CAD algorithms that were either employed or selected for inclusion in the project, and several technical aspects and results. RESULTS: We have built a standard-based platform with which users can request a CAD service and receive the results in their local PACS. The process runs through a web interface that allows sending data to the different CAD services. A DICOM SR object is received with the results of the algorithms stored inside the original study in the proper folder with the original images. CONCLUSIONS: As a result, a homogeneous service to the different hospitals of the region will be offered. End users will benefit from a homogeneous workflow and a standardised integration model to request and obtain results from CAD systems in any modality, not dependant on commercial integration models. This new solution will foster the deployment of these technologies in the entire region of Galicia.

Treatment of Intracranial Aneurysms With the SILK Embolization Device in a Multicenter Study. A Retrospective Data Analysis.

BACKGROUND: Flow-diverter technology has become an important stent-based embolization tool in the treatment of complex cerebrovascular pathology. We report here the experience of 4 Spanish centers with using the SILK flow-diverter (SFD) device. OBJECTIVE: To evaluate the safety and efficacy of using the SFD in the endovascular treatment of intracranial aneurysms with complex morphology. METHODS: We retrospectively examined a prospectively maintained database of patients treated with SFD devices between July 2008 and December 2013 at 1 of 4 institutions in Spain. Data regarding patient demographics, aneurysm characteristics, and technical procedure were analyzed. Angiographic and clinical findings were recorded during the procedure and at 12 months postoperatively. RESULTS: A total of 175 SFD devices were implanted in 157 patients (women/men: 119/38; mean, median, and range of age: 56.2, 56.7, and 19-80 years, respectively), who were treated in a delayed manner (3-6 months from the event) for 180 aneurysms (165 unruptured and 15 ruptured). Adverse events (acute and delayed) were observed in 28.7% of cases (45/157), and most were resolved (19.1%; 30/157). Six months after the procedure, total morbidity and mortality were 9.6% (15/157) and 3.2% (5/157), respectively. Long-term imaging follow-up showed complete occlusion, neck remnants, and residual aneurysm in 78.1% (100/128), 14.0% (18/128), and 7.8% (10/128) of cases, respectively. CONCLUSIONS: The SFD device is an effective tool for the treatment of challenging aneurysms, and allows complete occlusion within a year of the procedure in most patients, with morbidity and mortality comparable to those previously reported for similar devices.

Effects of JPEG2000 data compression on an automated system for detecting clustered microcalcifications in digital mammograms.

The functionalities of the JPEG2000 standard have led to its incorporation into digital imaging and communications in medicine (DICOM), which makes this compression method available for medical systems. In this study, we evaluated the compression of mammographic images with JPEG2000 (16 : 1, 20 : 1, 40 : 1, 60.4 : 1, 80: 1, and 106 : 1) for applications with a computer-aided detection (CAD) system for clusters of microcalcifications. Jackknife free-response receiver operating characteristic (JAFROC) analysis indicated that differences in the detection of clusters of microcalcifications were not statistically significant for uncompressed versus 16: 1 (T = -0.7780; p = 0.4370), 20 : 1 (T = 1.0361; p = 0.3007), and 40 : 1 (T = 1.6966; p = 0.0904); and statistically significant for uncompressed versus 60.4 : 1 (T = 5.8883; p < 0.008), 80 : 1 (T = 7.8414; p < 0.008), and 106 : 1 (T = 17.5034; p = < 0.008). Although there is a small difference in peak signal-to-noise ratio (PSNR) between compression ratios, the true-positive (TP) and false-positive (FP) rates, and the free-response receiver operating characteristic (FROC), figure of merit values considerably decreased from a 60 : 1 compression ratio. The performance of the CAD system is significantly reduced when using images compressed at ratios greater than 40 : 1 with JPEG2000 compared to uncompressed images. Mammographic images compressed up to 20 : 1 provide a percentage of correct detections by our CAD system similar to uncompressed images, regardless of the characteristics of the cluster. Further investigation is required to determine how JPEG2000 affects the detectability of clusters of microcalcifications as a function of their characteristics.

Automatic characterization of thoracic aortic aneurysms from CT images.

Accurate determination of the diameter is an important step for diagnosis and follow-up of aortic abnormalities such as aneurysms, caused by dilation of the vessel lumen. In this work we focus on the development of an automatic method for measuring the calibre of the thoracic aorta. The method is based on the application of principal component analysis on normal planes extracted from the aorta to establish the main axis of each section of the vessel. Two experiments were performed in order to test the accuracy and the rotational invariance of the developed method. Accuracy was determined by using a database of 15 clinical cases, where our method and a commercial software, which was considered as the gold standard, were compared. For the rotational invariance check, phantom images in different orientations were obtained and the diameter was measured with the proposed method. For clinical cases, a good agreement was observed between our method and the gold standard. The Bland Altman plots indicated that all of the values were within the acceptable limits of agreement with a bias of 0.2mm between both methods. For phantom cases, an ANOVA test revealed that the results achieved for the data sets acquired for the different orientations were not statistically different (F=1.88, p=0.153), which demonstrates the robustness of the method for rotations. The proposed method is applicable for measuring the diameter in all tested cases, and the results achieved underscored the capability of our approach for automatic characterization of thoracic aortic aneurysms.

Area Estimation of Deep-Sea Surfaces from Oblique Still Images.

Estimating the area of seabed surfaces from pictures or videos is an important problem in seafloor surveys. This task is complex to achieve with moving platforms such as submersibles, towed or remotely operated vehicles (ROV), where the recording camera is typically not static and provides an oblique view of the seafloor. A new method for obtaining seabed surface area estimates is presented here, using the classical set up of two laser devices fixed to the ROV frame projecting two parallel lines over the seabed. By combining lengths measured directly from the image containing the laser lines, the area of seabed surfaces is estimated, as well as the camera's distance to the seabed, pan and tilt angles. The only parameters required are the distance between the parallel laser lines and the camera's horizontal and vertical angles of view. The method was validated with a controlled in situ experiment using a deep-sea ROV, yielding an area estimate error of 1.5%. Further applications and generalizations of the method are discussed, with emphasis on deep-sea applications.

Region-based wavelet coding methods for digital mammography.

Spatial resolution and contrast sensitivity requirements for some types of medical image techniques, including mammography, delay the implementation of new digital technologies, namely, computer-aided diagnosis, picture archiving and communications systems, or teleradiology. In order to reduce transmission time and storage cost, an efficient data-compression scheme to reduce digital data without significant degradation of medical image quality is needed. In this study, we have applied two region-based compression methods to digital mammograms. In both methods, after segmenting the breast region, a region-based discrete wavelet transform is applied, followed by an object-based extension of the set partitioning in hierarchical trees (OB-SPIHT) coding algorithm in one method, and an object-based extension of the set partitioned embedded block (OB-SPECK) coding algorithm in the other. We have compared these specific implementations against the original SPIHT and the new standard JPEG 2000, both using reversible and irreversible filters, on five digital mammograms compressed at rates ranging from 0.1 to 1.0 bit per pixel (bbp). Distortion was evaluated for all images and compression rates by the peak signal-to-noise ratio. For all images, OB-SPIHT and OB-SPECK performed substantially better than the traditional SPIHT and JPEG 2000, and a slight difference in performance was found between them. A comparison applying SPIHT and the standard JPEG 2000 to the same set of images with the background pixels fixed to zero was also carried out, obtaining similar implementation as region-based methods. For digital mammography, region-based compression methods represent an improvement in compression efficiency from full-image methods, also providing the possibility of encoding multiple regions of interest independently.

Computer aided diagnosis for breast masses detection on a telemammography system.

A Computer-Aided Diagnosis (CAD) scheme for breast masses detection has been developed and integrated as a part of a telemammography system. This work derives from the close cooperation between the Laboratory for Radiologic Image Research of the University of Santiago de Compostela (Spain) and the company Intelsis Sistemas Inteligentes (Santiago de Compostela, Spain). This cooperation has been supported by funds from different projects, mainly from the European Union, the Spanish Health Administration, and the Galician Public Health's Service. As a result, a first prototype is ready to begin a demonstration project.

A high resolution workstation prototype for diagnosis of digital mammograms.

The development of a total digital high resolution mammography display system must meet a number of requirements that remain a challenge nowadays, most probably because of the special nature of breast imaging. In this paper, we discuss our particular approach to address some problems concerning the complexity of soft-copy diagnosis in digital mammography, such as image quality and user interface evaluation. Based on the experience obtained in the previous implementation of a medical image browser, a more ambitious project is being developed at the Department of Radiology of the University of Santiago de Compostela (Spain) in collaboration with the Department of Medical Informatics of INTELSIS, an emerging software company in our country. This new system will provide complete support to display, store and analyze mammographic studies in digital format.

A hybrid method based on level set and 3D region growing for segmentation of the thoracic aorta.

This study sought to develop a completely automatic method for image segmentation of the thoracic aorta. We used a total of 4682 images from 10 consecutive patients. The proposed method is based on the use of level set and region growing, automatically initialized using the Hough transform. The results obtained were compared to those of manual segmentation as performed by an external expert radiologist. Concordance between the developed method and manual segmentation ranged from 92.79 to 95.77% in the descending regions of the aorta and from 90.68 to 96.54% in the ascending regions, with a mean value of 93.83% being obtained for total segmentation.