Chest Radiography: New Technological Developments and Their Applications

Abstract

Digital chest radiography is still the most common radiological examination. With the upcoming three-dimensional (3D) acquisition techniques the value of radiography seems to diminish. But because radiography is inexpensive, readily available, and requires very little dose, it is still being used for the first-line detection of many cardiothoracic diseases. In the last decades major technical developments of this 2D technique are being achieved. First, hardware developments of digital radiography have improved the contrast to noise, dose efficacy, throughput, and workflow. Dual energy acquisition techniques reduce anatomical noise by splitting a chest radiograph into a soft tissue image and a bone image. Second, advanced processing methods are developed to enable and improve detection of many kinds of disease. Digital bone subtraction by a software algorithm mimics the soft tissue image normally acquired with dedicated hardware. Temporal subtraction aims to rule out anatomical structures clotting the image, by subtracting a current radiograph with a previous radiograph. Finally, computer-aided detection systems help radiologists for the detection of various kinds of disease such as pulmonary nodules or tuberculosis.

Development and Validation of a Deep Learning–Based Automated Detection Algorithm for Major Thoracic Diseases on Chest Radiographs

“… 7 Indeed, there have been several CAD systems that have achieved successful results for various thoracic diseases, including pulmonary nodules, 8 , 9 pulmonary tuberculosis, 10 , 11 and pneumothorax. 12 However, few CAD systems are presently used in clinical practice owing to their suboptimal performance (sensitivity, 47%-76% with 1.7-3.3 false-positives per image for lung nodules; area under the receiver operating characteristic curve [AUROC], 0.71-0.84 for pulmonary tuberculosis), 10 , 13 and specific target diseases limit their utility in general practice.…”

Efficiency and reporting confidence analysis of sequential dual-energy subtraction for thoracic x-ray examinations

“…Chest roentgenography is the main imaging technique in thoracic radiology. 1,2 Accurate and efficient use of imaging techniques such as CR decreases the need for CT as a secondary imaging technique, thus preventing additional radiation exposure. 3 The primary difficulty in assessing chest radiographs is the superimposition of several structures due to the projection of three-dimensional volumetric structures as a two-dimensional image.…”

“…5–10,14 To obtain subtracted images, the data from the raw image with the desired contrast are mathematically multiplied by two or three, and the other raw image is obtained from that enhanced image. 1,5…”

“…Routine posterior–anterior chest radiography (PA-CR) remains the mainstay for the diagnosis of many thoracic abnormalities. 1 Accurate and efficient evaluation of radiographs is crucial for avoiding unnecessary chest computed tomography (CT) examinations. 2–4 Generally, CT is preferred as a secondary imaging technique for accurate characterization of lesions previously detected using CR.…”

“…2 Using DES to highlight the tissue of interest, radiologists can achieve tissue-specific examination by the detection of energy levels at which the K-edge peak sensitivity is specific to that tissue. 1,4 Unlike PA-CR, DES may be used to obtain soft-tissue-subtracted images wherein bone structures remain in the background or bone-subtracted images wherein bone structures do not have soft tissue superimposed on them. 5 This property of DES is useful for evaluating obscured lesions in lung parenchyma, particularly for nodule detection.…”