The receiver operating characteristic (ROC) curve analysis was done to evaluate the effects of digital image processing techniques on the detectability of simulated pulmonary nodules and cysts in chest radiographs. Image processing techniques used were the contrast inversion, unsharp masking, and filtered equalization method. Simulated pulmonary nodules and cysts were generated by the computed program using Turbo-C language for personal computer. Each processed and unprocessed image sets of sixty images with pulmonary nodules and cysts and one hundred and twenty normal images were analyzed by three board-certified radiologists and four senior residents training in diagnostic radiology by five rating category. Area under the ROC curve was calculated using the trapezoidal rule. Mean area under the ROC curve of seven radiologists of the unprocessed image was 0.6360±0.0583, contrast inversion was 0.5660±0.0478, unsharp masking was 0.7534±0.0355 and filtered equalization was 0.6915±0.0472. Unsharp masking(p<0.01) and filtered equalization image(p<0.05) was statistically significant than unprocessed image. Digital chest radiographs processed by the unsharp masking method significantly increased the detectability of simulated pulmonary nodules and cysts overlapped with mediastinum and pulmonary cysts in free lung fields.
Lung ; Masks ; Mediastinum ; Methods ; Microcomputers ; Radiography, Thoracic* ; ROC Curve ; Thorax*

Precisely segmented lung fields restrict the region-of-interest from which radiological patterns are searched, and is thus an indispensable prerequisite step in any chest radiographic CADx system. Recently, a number of deep learning-based approaches have been proposed to implement this step. However, deep learning has its own limitations and cannot be used in resource-constrained settings. Medical systems generally have limited RAM, computational power, storage, and no GPUs. They are thus not always suited for running deep learning-based models. Shallow learning-based models with appropriately selected features give comparable performance but with modest resources. The present paper thus proposes a shallow learning-based method that makes use of 40 radiomic features to segment lung fields from chest radiographs. A distance regularized level set evolution (DRLSE) method along with other post-processing steps are used to refine its output. The proposed method is trained and tested using publicly available JSRT dataset. The testing results indicate that the performance of the proposed method is comparable to the state-of-the-art deep learning-based lung field segmentation (LFS) methods and better than other LFS methods.
Dataset ; Learning ; Lung ; Methods ; Radiography, Thoracic ; Running ; Thorax

PURPOSE: The purposes of this study were to evaluate the usefulness and limitations of chest radiographs in scoliosis screening and to compare these results with those of thoraco-lumbar standing radiographs (TLSR). MATERIALS AND METHODS: During Korean conscription, 419 males were retrospectively examined using both chest radiographs and TLSR to confirm the scoliosis and Cobb angle at the Regional Military Manpower. We compared the types of spinal curves and Cobb angles as measured from different radiographs. RESULTS: In the pattern of spinal curves, the overall matching rate of chest radiographs using TLSR was about 58.2% (244 of 419 cases). Cobb angle differences between chest radiographs and TLSR with meaningful difference was observed in 156 cases (37.2%); a relatively high proportion (9.5%) of Cobb angle differences more than 10 degrees was also observed. The matching rate of both spinal curve types and Cobb angle accuracy between chest radiographs and TLSR was 27.9% (117 among 419 cases). Chest radiographs for scoliosis screening were observed with 93.94% of sensitivity and 61.67% of specificity in thoracic curves; however, less than 40% of sensitivity (38.27%, 20.00%, and 25.80%) and more than 95% of specificity (97.34%, 99.69%, and 98.45%) were observed in thoraco-lumbar, lumbar, and double major curves, respectively. CONCLUSION: The accuracy of chest radiographs for scoliosis screening was low. The incidence of thoracic curve scoliosis was overestimated and lumbar curve scoliosis was easily missed by chest radiography. Scoliosis screening using chest radiography has limited values, nevertheless, it is useful method for detecting thoracic curve scoliosis.
Adult ; Humans ; Male ; Radiography, Thoracic/methods ; Retrospective Studies ; Scoliosis/*diagnosis/*radiography ; Young Adult

Dual-kilovolt technique was realized in dual energy X-ray imaging system with computer controlled KV adjustment, filter switching and image acquirement. The dual energy images can be obtained in 2-3 seconds to avoid moving artifact. Low energy photons in high energy X-ray beam can be attenuated effectively by a 2 mm Cu filter to separate the spectra of the high and low energy X-rays. A simplified dual energy decomposition method was used to obtain the soft tissue image. An example of chest dual energy radiographs is presented to illustrate the performance of the system.
Humans ; Radiography, Dual-Energy Scanned Projection ; methods ; Radiography, Thoracic ; Signal Processing, Computer-Assisted

OBJECTIVE: We observed patients in whom the fluid collection in the right lateral portion of the superior aortic recess on computed tomography (CT) scans mimicked a right anterior mediastinal mass on chest PA radiographs. The purpose of this study was to assess chest PA and CT features of these patients. MATERIALS AND METHODS: All chest PA radiographs and CT scans in 9 patients were reviewed by two radiologists on a consensus basis; for the presence of pleural effusion, pulmonary edema and heart size on chest PA radiographs. For the portion of the fluid collection in the superior aortic recess (SAR), a connection between the right lateral portion of the SAR (rSAR) and posterior portion of the SAR (pSAR) on CT scans, and the distance between the right lateral margin of the rSAR and the right lateral margin of the superior vena cava. RESULTS: Fluid collection in the rSAR on CT scans caused a right anterior mediastinal mass or a bulging contour on chest PA radiographs in all women patients. All patients showed cardiomegaly, five patients had pleural effusion, and two patients had mild pulmonary edema. Further, eight patients showed a connection between the rSAR and the pSAR. CONCLUSION: The characteristic features of these patients are the right anterior mediastinal mass-like opacity due to fluid collection in the rSAR, are bulging contour with a smooth margin and cardiomegaly regardless of pulmonary edema on the chest PA radiographs, and fluid connection between the rSAR and the pSAR on CT scans.
Aged ; Aged, 80 and over ; Aorta, Thoracic/*radiography ; Cardiomegaly/radiography ; Contrast Media/diagnostic use ; Diagnosis, Differential ; Female ; Humans ; Mediastinal Diseases/*radiography ; Middle Aged ; Pleural Effusion/*radiography ; Pulmonary Edema/*radiography ; Radiography, Thoracic/*methods ; Retrospective Studies ; Tomography, X-Ray Computed/*methods

In a PACS system, doctors can avoid the mistakes in filing chest radiographs by comparing the new image with the old ones from the same patient. An automatic method with digital image processing technology is introduced in the paper, which is realized by general location of anatomical structures, local image registration and BP artificial neural network, so as to achieve good results for identity recognition.
Neural Networks (Computer) ; Patient Identification Systems ; Radiographic Image Interpretation, Computer-Assisted ; methods ; Radiography, Thoracic ; methods

OBJECTIVETo study the consistency between DR and high-kV chest radiographs in diagnosis of pneumoconiosis and to explore the feasibility of DR chest radiograph in the diagnosis of pneumoconiosis.

METHODSTwenty five coal miners were examined with DR and high-kV chest radiographs at the same time. Image post-processing parameters (density, contrast, etc.) were set to ensure the quality of DR chest radiograph in Philips Essenta DR machine. In order to avoid the repetitive numbers, 50 chest radiographs were numbered at random. Pneumoconiosis diagnosis was conducted by six independent certified occupational physicians of pneumoconiosis by blind method. The consistency between 2 kinds of chest films was assessed.

RESULTSAll chest radiographs (25 cases, 50 chest films) were excellent. The diagnosis results of six readers on the 15 pairs of DR and high-kV chest radiographies were summarized. For high-kV chest radiographs, the consistency of pneumoconiosis classification for 12 pairs of readers was more than 68%, the consistency of total density for 11 pairs of readers was more than 68%. For DR chest radiographs, the consistency of pneumoconiosis classification for 13 pairs of readers was more than 60%, the consistency of total density for 14 pairs of readers was more than 60%. The consistency of pneumoconiosis classification between two chest radiographs was 72% (value: 0.69, 95% CI: 0.46-0.92), the consistency of total density between two chest radiographs was 80% (value: 0.78, 95% CI: 0.61-0.95).

CONCLUSIONWhen the chest radiograph quality was good and the difference of reading films was low, there was a good consistency of pneumoconiosis diagnosis between DR chest radiographs and high-kV chest radiographs.

OBJECTIVETo explore the effects of image post-processing parameters on DR chest radiograph for the diagnosis of pneumoconiosis.

METHODSEighty three coal miners were examined with high-kV and DR chest radiographs at the same time. Image post-processing parameters (density, contrast and so on) were designed in a Philips Essenta DR machine were designed, then differences of image quality between high-kV and DR chest radiographs were compared.

RESULTSAfter regulating image and proceeding the parameters, the OD (optical density) values of high density areas in the upper-middle lung fields, subphrenic and direct exposure areas were 1.58 +/- 0.10, 0.23 +/- 0.02 and 2.80 +/- 0.21, respectively. The quality of chest films met the requirements of diagnostic criteria of pneumoconiosis. The rate of excellent chest films for DR chest radiograph was 95.18%, which was significantly higher than that (80.72%) for high-kV chest radiograph (P < 0.01).

CONCLUSIONAppropriate parameters of image post-processing can make DR chest radiograph to meet the requirements of chest radiograph quality for the diagnosis of pneumoconiosis.

Forty canine patients with a presumptive diagnosis of the intervertebral disc herniation at the thoracolumbar region were imaged. A neurological examination was performed and all patients were classified under four grades by the examination. The degrees of attenuation of the herniated disc material were measured in Housefield units (HU) in each image. The ratio of the area to herniated disc material and the height to disc material were measured. The clinical grade was correlated with the area ratio of the herniated disc material to the spinal cord, but not correlated with the height ratio of that. In the patients with epidural hemorrhage at surgery, HUs of the herniated disc material was lower than those with no epidural hemorrhage at surgery. Non-contrast computed tomography scans of the spine can be useful in diagnosing acute intervertebral disc disease in chondrodystrophoid breeds, evaluating patient status and identifying concurrent epidural hemorrhage.
Animals ; Dog Diseases/*pathology/radiography ; Dogs ; Intervertebral Disk Displacement/radiography/*veterinary ; Lumbar Vertebrae/*pathology/radiography ; Retrospective Studies ; Thoracic Vertebrae/*pathology/radiography ; Tomography, X-Ray Computed/methods/standards/*veterinary

We report here on a new technique using polymethylmethacrylate to manage vertebral osteoporotic compression fractures in three patients. These patients presented with acute back pain that manifested itself after minor trauma. Osteoporotic compression fractures were diagnosed via plain X-ray and magnetic resonance imaging studies. The patients were treated with absolute bed rest and non-steroidal anti-inflammatory drugs. Despite of the conservative treatment, the patients experienced severe, recalcitrant and progressive pain. The vertebrae were collapsed over 50% or kyphotic deformity was seen on the radiologic materials. We performed a new technique called lordoplasty, which is derived from percutaneous vertebroplasty. The patients experienced a reduction in pain after the procedure. The wedge and kyphotic angles of the fractured vertebrae were significantly restored.
Aged ; Female ; Fractures, Compression/radiography/*surgery ; Humans ; Magnetic Resonance Imaging ; Orthopedic Procedures/*methods ; Osteoporotic Fractures/radiography/*surgery ; Spinal Fractures/radiography/*surgery ; Thoracic Vertebrae/*injuries/radiography/surgery