Automatic lung segmentation in COVID-19 patients: Impact on quantitative computed tomography analysis.

PURPOSE: To assess the impact of lung segmentation accuracy in an automatic pipeline for quantitative analysis of CT images. METHODS: Four different platforms for automatic lung segmentation based on convolutional neural network (CNN), region-growing technique and atlas-based algorithm were considered. The platforms were tested using CT images of 55 COVID-19 patients with severe lung impairment. Four radiologists assessed the segmentations using a 5-point qualitative score (QS). For each CT series, a manually revised reference segmentation (RS) was obtained. Histogram-based quantitative metrics (QM) were calculated from CT histogram using lung segmentationsfrom all platforms and RS. Dice index (DI) and differences of QMs (ΔQMs) were calculated between RS and other segmentations. RESULTS: Highest QS and lower ΔQMs values were associated to the CNN algorithm. However, only 45% CNN segmentations were judged to need no or only minimal corrections, and in only 17 cases (31%), automatic segmentations provided RS without manual corrections. Median values of the DI for the four algorithms ranged from 0.993 to 0.904. Significant differences for all QMs calculated between automatic segmentations and RS were found both when data were pooled together and stratified according to QS, indicating a relationship between qualitative and quantitative measurements. The most unstable QM was the histogram 90th percentile, with median ΔQMs values ranging from 10HU and 158HU between different algorithms. CONCLUSIONS: None of tested algorithms provided fully reliable segmentation. Segmentation accuracy impacts differently on different quantitative metrics, and each of them should be individually evaluated according to the purpose of subsequent analyses.

A patient-specific approach for quantitative and automatic analysis of computed tomography images in lung disease: Application to COVID-19 patients.

PURPOSE: Quantitative metrics in lung computed tomography (CT) images have been widely used, often without a clear connection with physiology. This work proposes a patient-independent model for the estimation of well-aerated volume of lungs in CT images (WAVE). METHODS: A Gaussian fit, with mean (Mu.f) and width (Sigma.f) values, was applied to the lower CT histogram data points of the lung to provide the estimation of the well-aerated lung volume (WAVE.f). Independence from CT reconstruction parameters and respiratory cycle was analysed using healthy lung CT images and 4DCT acquisitions. The Gaussian metrics and first order radiomic features calculated for a third cohort of COVID-19 patients were compared with those relative to healthy lungs. Each lung was further segmented in 24 subregions and a new biomarker derived from Gaussian fit parameter Mu.f was proposed to represent the local density changes. RESULTS: WAVE.f resulted independent from the respiratory motion in 80% of the cases. Differences of 1%, 2% and up to 14% resulted comparing a moderate iterative strength and FBP algorithm, 1 and 3 mm of slice thickness and different reconstruction kernel. Healthy subjects were significantly different from COVID-19 patients for all the metrics calculated. Graphical representation of the local biomarker provides spatial and quantitative information in a single 2D picture. CONCLUSIONS: Unlike other metrics based on fixed histogram thresholds, this model is able to consider the inter- and intra-subject variability. In addition, it defines a local biomarker to quantify the severity of the disease, independently of the observer.

On skin dose estimation software in interventional radiology.

In recent years, a growing interest has been shown in the implementation of software dedicated to the skin dose calculation, since the Fluoroscopically Guided Interventions are expanding in various medical areas. In this regard, a review article recently published by Malchair et al. (2020) is of great importance as it provides the reader with useful references to the software currently available to estimate the patient's skin dose. Despite the usefulness of collecting and summarizing in one paper the different software solutions, a few critical issues have emerged related to some parameters and configurations used in the estimation; additional details concerning patient's size and position can be added to the information cited by the authors, giving greater robustness to the software calculation. Furthermore, software results cited in the benchmarking without reference cause a lack of solid information. Our suggestion is to adopt the given criteria to evaluate every available software solutions thus helping the eventual user to analyse the tool before adopting it.

Digital breast tomosynthesis: Dose and image quality assessment.

The aim of this work was to evaluate how different acquisition geometries and reconstruction parameters affect the performance of four digital breast tomosynthesis (DBT) systems (Senographe Essential - GE, Mammomat Inspiration - Siemens, Selenia Dimensions - Hologic and Amulet Innovality - Fujifilm) on the basis of a physical characterization. Average Glandular Dose (AGD) and image quality parameters such as in-plane/in-depth resolution, signal difference to noise ratio (SDNR) and artefact spread function (ASF) were examined. Measured AGD values resulted below EUREF limits for 2D imaging. A large variability was recorded among the investigated systems: the mean dose ratio DBT/2D ranged between 1.1 and 1.9. In-plane resolution was in the range: 2.2mm-1-3.8mm-1 in chest wall-nipple direction. A worse resolution was found for all devices in tube travel direction. In-depth resolution improved with increasing scan angle but was also affected by the choice of reconstruction and post-processing algorithms. The highest z-resolution was provided by Siemens (50°, FWHM=2.3mm) followed by GE (25°, FWHM=2.8mm), while the Fujifilm HR showed the lowest one, despite its wide scan angle (40°, FWHM=4.1mm). The ASF was dependent on scan angle: smaller range systems showed wider ASF curves; however a clear relationship was not found between scan angle and ASF, due to the different post processing and reconstruction algorithms. SDNR analysis, performed on Fujifilm system, demonstrated that pixel binning improves detectability for a fixed dose/projection. In conclusion, we provide a performance comparison among four DBT systems under a clinical acquisition mode.

Could anti-HCV treatment prevent recurrence of hepatocellular carcinoma in HIV-infected patients? Two case reports.

Highly active antiretroviral therapy (HAART) has proven long-term efficacy in human immunodeficiency virus (HIV) infection. Combination therapy with pegylated interferon and ribavirin has become the standard of care in patients with both hepatitis C virus (HCV) chronic hepatitis and HIV/HCV co-infection. Data on the safety and efficacy of combination therapy in chronic hepatitis C patients with hepatocellular carcinoma (HCC) is scarce and even more so in HIV/HCV co-infected subjects. We report the successful administration of both HAART and anti-HCV therapies in two HIV/HCV co-infected patients after HCC eradication. These encouraging results might argue for the feasibility of an aggressive approach in the management of co-infected patients with HCC.

Clinical presentation and outcome of squamous cell carcinoma of the anus in HIV-infected patients in the HAART-era: a GICAT experience.

INTRODUCTION: Squamous cell carcinoma of the anus (SCCA) is a relatively uncommon cancer. In the HIV-positive patients the introduction of the highly active antiretroviral therapy (HAART) did not change the incidence of SCCA. BACKGROUND AND OBJECTIVES: This paper describes the Italian Cooperative Group on AIDS and Tumours (GICAT) experience on HIV-positive patients with SCCA. The purposes of this retrospective study were: first to describe the clinical presentation and outcome of HIV-positive patients with SCCA, second to compare them with the ones reported in the literature. PATIENTS AND METHODS: Between July 2000 and March 2010 we retrospectively collected epidemiological, clinical and survival data from 65 patients with SCCA in HIV infection enrolled within the GICAT. RESULTS: Fifty-three (81.5%) patients were male. The majority of patients (40%) were homosexual Forty-three patients (66.1%) were diagnosed with HIV before 1996. Thirty-five patients (54%) had CD4-positive cells count > 200 / mm3 and 28 patients (43%) had viral load > 50 cp / ml at the time of SCCA diagnosis. The median time difference between HIV and SCCA diagnosis was 120 months (range 10-282 months). Sixty-one patients (96.8%) received HAART at SCCA diagnosis. Fifty-two patients (80%) had performance status (PS) 0-1 at the time of SCCA diagnosis. Twenty-seven patients (41.5%) underwent surgery with curative intent. Thirty-five patients (53.9%) were given combined modality therapy (CMT) consisting of pelvic radiotherapy with concurrent chemotherapy. No grade 3/4 haematological or extra-haematological effects were observed in our patients. CONCLUSIONS: In summary, despite the retrospective nature of analysis, the absence of patient strict criteria of inclusion/exclusion, our data on HIV-positive patients with SCCA, compared both to general population and to small reports on HIV-positive patients present in the literature, are promising.

Neuronavigation accuracy dependence on CT and MR imaging parameters: a phantom-based study.

Clinical benefits from neuronavigation are well established. However, the complexity of its technical environment requires a careful evaluation of different types of errors. In this work, a detailed phantom study which investigates the accuracy in a neuronavigation procedure is presented. The dependence on many different imaging parameters, such as field of view, slice thickness and different kind of sequences (sequential and spiral for CT, T1-weighted and T2-weighted for MRI), is quantified. Moreover, data based on CT images are compared to those based on MR images, taking into account MRI distortion. Finally, the contributions to global accuracy coming from image acquisition, registration and navigation itself are discussed. Results demonstrate the importance of imaging accuracy. Procedures based on CT proved to be more accurate than procedures based on MRI. In the former, values from 2 to 2.5 mm are obtained for 95% fractiles of cumulative distribution of Euclidean distances between the intended target and the reached one while, in the latter, the measured values range from 3 to 4 mm. The absence of imaging distortion proved to be crucial for registration accuracy in MR-based procedures.

Treatment planning for radiotherapy in northern Italy: a survey by the National AIFB-AIRO Committee on 3D-Treatment Planning. Italian Association for Biomedical Physics. Italian Association for Radiation Oncology.

BACKGROUND AND PURPOSE: A survey was performed in 1996 to investigate the structures and the process of radiation therapy treatment planning in clinical practice within northern Italy, with particular emphasis on the current and future implementation of 3D equipment and techniques. MATERIALS AND METHODS: Of 57 existing radiation therapy (RT) centres covering a population of 25 million people (45% of the total population of Italy) and treating over 58,000 cancer patients (70% of the cancer cases in Italy) each year, 46 centres were deemed eligible for the survey; a questionnaire was sent to a medical physicist working in each eligible RT centre, 40 of whom responded, making the basis for this report. RESULTS: A dedicated CT scanner was available in 25% of the responding centres and a total of 49 radiation therapy planning systems (RTPS) were reported; none of the RTPS were able to perform 3D calculations, but 50% of the centres had an advanced 2D or 2.5D system. Connection between CT scan and RTPS was by tape or disk in 62% of centres. Immobilization devices were used frequently for head and neck patients (88% of centres), but not for lung (16%) or prostate cancer (24%) patients; the number of contoured slices was largely variable, exceeding 10 in only about 30% of the responding centres. The average working time per patient seemed to closely reflect the number of slices used and the number of critical organs contoured. Finally, the majority of the responding physicists did not favour the use of more than 20 CT slices for 3D treatment planning, nor did they forecast a general spread of this technique in the next 2-3 years. CONCLUSIONS: This survey has shown (1) a heterogeneous picture, with 20% of centres ready to implement 3D techniques and 20% of centres lacking the possibility of planning treatments and (2) a general difficulty in coping with the workload represented by 3D treatment planning.

The long-term efficacy and safety of two different corticosteroids in chronic sarcoidosis.

Deflazacort (DFZ) is claimed to have fewer adverse bone effects than prednisone (PDN) at doses with equivalent anti-inflammatory activity (5 mg PDN = 6 mg DFZ). However, its safety over the long-term has never been tested in a controlled trial. The aim of the present study was to assess prospectively the safety and efficacy of DFZ compared with PDN in previously untreated patients with chronic, histologically proven sarcoidosis needing long-term (> or = 2 yr) corticosteroid therapy. Thirty-six patients were treated with PDN for 32 +/- 18 months and 36 patients were treated with DFZ for 42 +/- 18 months, and followed-up with periodic chest X-ray, 67Gallium lung scan, angiotensin converting enzyme (ACE), serum and urinary calcium levels, spirometry, alveolar diffusion (DLCO) arterial oxygen tension (PaO2), bone mineral content (BMC) (by computed tomography), and a complete biochemical and haematological profile. The two groups were similar as regards sex, age, pulmonary and extrapulmonary involvement, parameters of activity and impairment, and initial BMC. Daily starting doses were 23.2 +/- 11.4 mg DFZ and 22.3 +/- 6.9 mg PDN. One year of trial was completed by 69 patients, 2 yr by 59 patients, 3 yr by 46 patients and 4 yr by 24 patients. Some patients were followed-up for 5-7 yr. The mean daily dose over the whole period was 15 +/- 10 mg DFZ and 10 +/- 6 PDN, starting from 21 +/- 9 and 15 +/- 8 mg in the first year, and progressively declining to a mean of 9 +/- 6 mg in both groups in the fourth year. Chest X-ray, 67Ga score, ACE and forced vital capacity improved significantly in both groups. Urine total calcium improved significantly in the PDN group (345 +/- 27 to 186 +/- 47; P < 0.05) with a similar but non-significant pattern in the DFZ group (270 +/- 28 to 207 +/- 39). Non-significant improvements were observed in DLCO, PaO2 and forced expiratory volume in 1 s in both groups. Drug-related adverse events were more frequent in the PDN group, causing discontinuation of the drug in four PDN patients. Body weight increased mainly in the PDN group [69.9 +/- 0.4 to 73.6 +/- 0.8 kg vs 70.1 +/- 0.4 to 70.0 +/- 0.6 kg in the DFZ group (P < 0.01)]. Bone mineral content dropped under the fracture threshold in most PDN patients, who thus appeared at higher risk for fractures. In fact, six atraumatic skeletal fractures were observed in this group but only one in the DFZ group. Two further patients in the DFZ group and eight in the PDN group were obliged to start corrective measures for bone loss and/or bone pain. At the end of the study, 21 patients (12 DFZ, nine PDN) no longer needed corticosteroids, and the others were taking a maintenance daily dose that controlled the disease adequately. In conclusion, DFZ appeared as effective as PDN in the long-term treatment of chronic sarcoidosis, and it may have fewer side-effects, especially on bone.

AIDS related neoplasms in Genoa, Italy.

The study defines the epidemiological characteristics of HIV-infection in the population of Genoa and estimates the entity of AIDS-cancer association. The cohort includes 317 subjects resident in the Municipality of Genoa, aged above 14 years and notified prior to 31 December 1991 and/or dead from AIDS in the period 1988-1991. From 1984 to 1991, 44 cases of tumour were recorded. The comparison between the rate ratios found in the AIDS patients' cohort and in the general population of Genoa strengthen the significant association highlighted in literature regarding overall cancer, 26.7 (p < 0.05), and in particular, Kaposi's sarcoma, 3239.4 (p < 0.05); non-Hodgkin's lymphomas, 84.8 (p < 0.05); Hodgkin's lymphomas, 20.6 (p < 0.05). Moreover, a significant increase in the risk of testicular seminoma, 61.5 (p < 0.05) and lung cancer, 18.0 (p < 0.05) is confirmed.

[Proposal of a method of automatic interpretation of images in x-ray computed tomography]. / Proposition de méthode d'interprétation automatique d'images obtenues en tomodensitométrie.

A preliminary study is described relative to the possibility of using methods of automatic image interpretation in the field of biomedical images. These general methods are capable of recognizing characteristic shapes inside the image. In this paper, the structures are described and interpreted. These methods are capable of outlining shapes which are important from a clinical point of view--e.g., spine, vertebrae. They can also evaluate the shapes by plausible methods, to explain the meaning of the whole image. A feasibility study is described concerning the automatic recognition of vertebral contour in axial CT images. The results suggest that the employed techniques can be used in real diagnostic applications.

[Rhodococcus equi infections in AIDS: personal cases]. / Sepsi da Rhodococcus equi in corso di AIDS: osservazioni personali.

We report on the occurrence of an uncommon pathogen, Rhodococcus equi (R.e.) in HIV infection. In the period february 1990-July 1991 we performed the diagnosis of R.e. infection (lung, lung-central nervous system) in two infected patients, aged 27 and 31 years, both males, drug addicts, classified as CDC IV. In the first of them an cavitating right bronchopneumonia (bpm) was diagnosed as of tuberculous origin, on the ground of the microscopic demonstration of an acid-fast, gram-positive strain in b.a.l.. A standard antituberculous regimen was uneffective and R.e. was eventually isolated in three blood culture taken shortly before the exitus and at post-mortem examination of the lungs. In the second patient a subclavian right bpm developed without microbiological evidence of any common pathogen. A third-generation cephalosporin course was only partially successful (clinical amelioration, incomplete clearing of radiological findings). After 3 months the patient relapsed and an aseptic meningitis developed. Cultures of blood and csf yielded a R.e. strain; post-mortem examination revealed a diffuse, cavitating bpm. Our personal experience underlines the difficulty in recognizing R.e. infections in compromised host, because of similarity to other entities (i.e. tuberculosis) and the absence of pathognomonic hints.

[A proposed method for the automatic interpretation of images obtained by computer tomography]. / Proposta di un metodo di interpretazione automatica di immagini ottenute con tomografia computerizzata.

A preliminary study is described relative to the possibility of using methods of automatic image interpretation in the field of biomedical images. These general methods are capable of recognizing characteristic shapes inside the image. In this paper the structures are described and interpreted. These methods are capable of outlining shapes which are important from a clinical point of view--e.g., spine, vertebrae. They can also evaluate the shapes by plausible methods, to explain the meaning of the whole image. A feasibility study is described concerning the automatic recognition of vertebral contour in axial CT images. The results suggest that the employed techniques can be used in real diagnostic applications.