Chest x-ray in the COVID-19 pandemic: Radiologists' real-world reader performance.

PURPOSE: To report real-world diagnostic performance of chest x-ray (CXR) readings during the COVID-19 pandemic. METHODS: In this retrospective observational study we enrolled all patients presenting to the emergency department of a Milan-based university hospital from February 24th to April 8th 2020 who underwent nasopharyngeal swab for reverse transcriptase-polymerase chain reaction (RT-PCR) and anteroposterior bedside CXR within 12 h. A composite reference standard combining RT-PCR results with phone-call-based anamnesis was obtained. Radiologists were grouped by CXR reading experience (Group-1, >10 years; Group-2, <10 years), diagnostic performance indexes were calculated for each radiologist and for the two groups. RESULTS: Group-1 read 435 CXRs (77.0 % disease prevalence): sensitivity was 89.0 %, specificity 66.0 %, accuracy 83.7 %. Group-2 read 100 CXRs (73.0 % prevalence): sensitivity was 89.0 %, specificity 40.7 %, accuracy 76.0 %. During the first half of the outbreak (195 CXRs, 66.7 % disease prevalence), overall sensitivity was 80.8 %, specificity 67.7 %, accuracy 76.4 %, Group-1 sensitivity being similar to Group-2 (80.6 % versus 81.5 %, respectively) but higher specificity (74.0 % versus 46.7 %) and accuracy (78.4 % versus 69.0 %). During the second half (340 CXRs, 81.8 % prevalence), overall sensitivity increased to 92.8 %, specificity dropped to 53.2 %, accuracy increased to 85.6 %, this pattern mirrored in both groups, with decreased specificity (Group-1, 58.0 %; Group-2, 33.3 %) but increased sensitivity (92.7 % and 93.5 %) and accuracy (86.5 % and 81.0 %, respectively). CONCLUSIONS: Real-world CXR diagnostic performance during the COVID-19 pandemic showed overall high sensitivity with higher specificity for more experienced radiologists. The increase in accuracy over time strengthens CXR role as a first line examination in suspected COVID-19 patients.

Multi-Rater Agreement Using the Adapted Fracture Healing Scale (AFHS) for the Assessment of Tubular Bones on Conventional Radiographs: Preliminary Study.

Better understanding of the timing of fracture healing may help in cases of interpersonal violence but also of personal identification. The intra- and inter-rater agreement for the adapted fracture healing scale (AFHS) assessing the post-traumatic time interval on radiographs were tested. This is a preliminary study, providing essential information on method reliability for upcoming studies using the AFHS. Five raters (two radiologists, a forensic pathologist, an orthopedist, and an anthropologist) were presented with a test in three parts consisting of 85 radiographs (from 30 adults) of fractures of tubular bones in different stages of healing purposefully selected from more than 1500 radiographs. The raters were firstly asked to assess 15 features describing fracture healing as present, absent, or not assessable. Thereafter, the raters were asked to choose from the AFHS a single-stage best representing the observed healing pattern. The intra- and inter-rater agreement were assessed using single-rating, absolute agreement, two-way mixed-effects intra-class correlation (ICC) coefficients. The intra-rater ICC of radiologist 1 ranged from 0.80 to 0.94. The radiologists' inter-rater ICC ranged from 0.68 to 0.74, while it ranged from -0.01 to 0.90 for the other raters. The good to excellent ICC among the radiologists and forensic anthropologist provides good foundation for the use of the AFHS in forensic cases of trauma dating. The poor to good results for the other physicians indicate that using the AFHS requires training in skeletal anatomy and radiology.

MRI radiomics-based machine-learning classification of bone chondrosarcoma.

PURPOSE: To evaluate the diagnostic performance of machine learning for discrimination between low-grade and high-grade cartilaginous bone tumors based on radiomic parameters extracted from unenhanced magnetic resonance imaging (MRI). METHODS: We retrospectively enrolled 58 patients with histologically-proven low-grade/atypical cartilaginous tumor of the appendicular skeleton (n = 26) or higher-grade chondrosarcoma (n = 32, including 16 appendicular and 16 axial lesions). They were randomly divided into training (n = 42) and test (n = 16) groups for model tuning and testing, respectively. All tumors were manually segmented on T1-weighted and T2-weighted images by drawing bidimensional regions of interest, which were used for first order and texture feature extraction. A Random Forest wrapper was employed for feature selection. The resulting dataset was used to train a locally weighted ensemble classifier (AdaboostM1). Its performance was assessed via 10-fold cross-validation on the training data and then on the previously unseen test set. Thereafter, an experienced musculoskeletal radiologist blinded to histological and radiomic data qualitatively evaluated the cartilaginous tumors in the test group. RESULTS: After feature selection, the dataset was reduced to 4 features extracted from T1-weighted images. AdaboostM1 correctly classified 85.7 % and 75 % of the lesions in the training and test groups, respectively. The corresponding areas under the receiver operating characteristic curve were 0.85 and 0.78. The radiologist correctly graded 81.3 % of the lesions. There was no significant difference in performance between the radiologist and machine learning classifier (P = 0.453). CONCLUSIONS: Our machine learning approach showed good diagnostic performance for classification of low-to-high grade cartilaginous bone tumors and could prove a valuable aid in preoperative tumor characterization.

Fast thoracic MRI as an alternative to chest x-ray: A retrospective evaluation of 287 patients.

PURPOSE: To compare half-Fourier acquisition single-shot turbo spin-echo thoracic MRI (HASTE-MRI) with chest x-ray (CXR). METHODS: A total of 287 patients (median age 53 years) undergoing both axial HASTE-MRI and CXR (<7 days apart) were retrospectively analyzed. Pulmonary nodules and consolidations, pleural effusion, and cardiac or aortic enlargement were considered. Detection rate (DR) and intra- and inter-technique agreement for both HASTE-MRI and CXR, were assessed. RESULTS: Pulmonary nodule DR was 1.7% (5/287) at both techniques (perfect inter-technique agreement); inter-reader agreement was perfect for HASTE-MRI (κ = 1.000) and modest for CXR (κ = 0.393). Pleural effusion DR at HASTE-MRI (19.1%, 55/287) was higher (p < 0.001) than at CXR (13.9%, 40/287), but their agreement was almost perfect (κ = 0.812); inter-reader agreement was almost perfect for HASTE-MRI (κ = 0.902) and substantial for CXR (κ = 0.773). Pulmonary consolidation DR at HASTE-MRI (8.4%, 24/287) was similar (p = 0.625) to that at CXR (7.7%, 22/287), with an almost perfect inter-technique agreement (κ = 0.905); inter-reader agreement was moderate for both HASTE-MRI (κ = 0.639) and CXR (κ = 0.554). Cardiac enlargement DR at HASTE-MRI (45.3%, 130/287) was borderline significantly lower (p = 0.057) than that at CXR (48.1%, 138/287), with an almost perfect inter-technique agreement (κ = 0.902); inter-reader agreement was substantial for both HASTE-MRI (κ = 0.798) and CXR (κ = 0.744). Aortic dilation DR at HASTE-MRI (17.7%, 51/287) was significantly higher (p < 0.001) than that at CXR (9.7%, 28/287), with a substantial inter-technique agreement (κ = 0.648); inter-reader agreement was moderate for both HASTE-MRI (κ = 0.724) and CXR (κ = 0.346). CONCLUSION: HASTE-MRI and CXR showed at least a comparable DR for thoracic cardiac and non-cardiac findings.

The synergy between radiographic and macroscopic observation of skeletal lesions on dry bone.

The diagnosis of bone lesions is a fundamental part of the study of skeletal remains, both in the archeological and forensic context. On the one side, the literature proved the relevance of radiography for the detection of bone lesions; on the other side, the careful macroscopic observation of the morphology of bone lesions is often underestimated. For this study, we examined and performed plain radiography on 14 skeletons of the CAL Milano Cemetery Skeletal Collection diagnosed with rheumatoid arthritis, diabetes, multiple myeloma, metastatic cancer, and osteomalacia to compare the macroscopic morphology and radiographic visualization of bone lesions. At least 200 osteolytic lesions and 65 areas of proliferative bone reaction (either spongiosclerotic or periosteal) were studied. We realized "comparative sets" of macroscopic pictures and radiographic imaging of the same skeletal elements to allow comparisons of detection and recognition of bone lesions. As a result, while trabecular lesions may be lost through naked eye observation, many lesions can also be unperceived on radiographs due to contrast, including periosteal reactions, osteolytic lesions, and spongiosclerosis. The aim of this research was to investigate the strengths and pitfalls of digital radiography and macroscopic analysis and to demonstrate the synergy of a complementary approach between the two methods for lesion analysis in dry bone.

CT-MRI LI-RADS v2017: A Comprehensive Guide for Beginners.

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy and the second leading cause of cancer-related deceases worldwide. Early diagnosis is essential for correct management and improvement of prognosis. Proposed for the first time in 2011 and updated for the last time in 2017, the Liver Imaging-Reporting and Data System (LI-RADS) is a comprehensive system for standardized interpretation and reporting of computed tomography (CT) and magnetic resonance imaging (MRI) liver examinations, endorsed by the American College of Radiology to achieve congruence with HCC diagnostic criteria in at-risk populations. Understanding its algorithm is fundamental to correctly apply LI-RADS in clinical practice. In this pictorial review, we provide a guide for beginners, explaining LI-RADS indications, describing major and ancillary features and eventually elucidating the diagnostic algorithm with the use of some clinical examples.

1H- and 31P-myocardial magnetic resonance spectroscopy in non-obstructive hypertrophic cardiomyopathy patients and competitive athletes.

PURPOSE: The clinical differentiation between athlete's heart and mild forms of non-obstructive hypertrophic cardiomyopathy (HCM) is crucial. We hypothesized that differences do exist between the myocardial metabolism of patients with non-obstructive HCM and competitive athletes (CAs). Our aim was to evaluate myocardial metabolism with 31P-MRS and 1H-MRS in HCM patients and CAs. MATERIALS AND METHODS: After Ethics Committee approval, 15 CAs and 7 HCM patients were prospectively enrolled. They underwent a 1.5-T cardiac MR including electrocardiographically triggered cine images, single-voxel 1H-MRS and multivoxel 31P-MRS. 1H-MRS was performed after imaging using standard coil with the patient in the supine position; thereafter, 31P-MRS was performed using a dedicated coil, in the prone position. Data were reported as median and interquartile range. Mann-Whitney U test was used. RESULTS: In CAs, left ventricular mass index was 72 (66-83) g/m2, septal thickness 10 (10-11) mm, end diastolic volume index 95 (85-102) ml/m2, end systolic volume index 30 (28-32) ml/m2 and ejection fraction 68% (65-69%); in HCM patients, 81 (76-111) g/m2 (P = 0.052), 18 (15-21) mm (P = 0.003), 73 (58-76) ml/m2 (P = 0.029), 20 (16-34) ml/m2 (P = 0.274) and 68% (55-73%) (P = 1.000), respectively. At 1H-MRS, total lipids were 35 (0-183) arbitrary units (au) for CA and 763 (155-1994) au for HCM patients (P = 0.046). At 31P-MRS, PCr/γATP was 5 (4-6) au for CA and 4 (2-5) au for HCM patients (P = 0.230). Examination time was 20 min for imaging only, 5 min for 1H-MRS and 15 min for 31P-MRS. CONCLUSIONS: We observed a significant increase of myocardial lipids, but a preserved PCr/γATP ratio in the metabolism of HCM patients compared with competitive CAs.