Computerized analysis of interstitial disease in chest radiographs: improvement of geometric-pattern feature analysis

We have been developing automated computerized schemes to assist radiologists in interpreting chest radiographs for interstitial disease based on texture analysis and geometric-pattern feature analysis. In this study, we attempted to improve the performance of the geometric-pattern feature analysis, because the current classification performance with geometric-pattern feature analysis is considerably lower than that of texture analysis. In order to improve the performance in distinguishing between normal lungs and abnormal lungs with interstitial disease, we attempted to remove rib edges in regions of interest (ROIs) by using an edge detection technique, and also to reduce false positives by using feature analysis techniques. In addition, the effects of many parameters on classification performance were investigated to identify proper threshold levels, and subsequently the specificity of the geometric-pattern feature analysis was improved from 69.5% to 86.1% at a sensitivity of 95.0%. Using a combined rule-based method with texture analysis and geometric-pattern feature analysis plus the artificial neural network (ANN) method for classification, a high specificity of 96.1% was obtained at a sensitivity of 95.0%.     

Regarding Kumar et al. IJROBP 31(3):477-483; 1995

OBJECTIVE: We present a computer-aided diagnostic technique for identifying nodular interstitial lung disease on chest radiographs. The fractal dimension was used as a numerical measure of image texture on digital chest radiographs to distinguish patients with normal lung from those with a diffuse nodular interstitial abnormality. MATERIALS AND METHODS: Twenty digitized chest radiographs were classified as normal (n = 10) or as containing diffuse nodular abnormality (n = 10) on the basis of readings assigned according to the classification of the International Labour Organization. Regions of interest (ROIs) measuring 1.28 cm2 were selected from the intercostal spaces of these radiographs. The fractal dimension of these ROIs was estimated by power spectrum analysis. The cases were not subtle. RESULTS: The fractal dimension provided statistically significant discrimination between normal parenchyma and nodular interstitial lung disease. The area under the receiver operating characteristic curve was 0.90 (+/- 0.02). One operating point provides sensitivity of 88% with a specificity of 80%. CONCLUSION: The fractal dimension can provide a measure of lung parenchymal texture and shows promise as an element of computer-aided diagnosis, characterization, and follow-up of interstitial lung disease.     

Computer-aided diagnosis in chest radiography. Preliminary experience

RATIONALE AND OBJECTIVES: Computer-aided diagnosis (CAD) schemes for chest radiography are being developed with which to alert radiologists to possible lesions, and thus potentially improve diagnostic accuracy. However, CAD schemes have not been tested on a large number of clinical cases. The authors identify design parameters that would be required for development of an intelligent workstation. METHODS: Computer-aided diagnosis programs were applied for the automated detection of lung nodules, cardiomegaly, and interstitial infiltrates to 310 consecutive chest radiographs, and were analyzed for potential usefulness and limitations. Computer-aided diagnosis output was evaluated by radiologists and physicists for accuracy and technical problems, respectively. RESULTS: Approximately 70% of the results were judged to be potentially acceptable; however, the number of false-positive findings was relatively high. Technical problems included failure to detect subtle abnormalities and the occurrence of false-positive detections caused by normal anatomical structures. CONCLUSION: Computer-aided diagnosis has the potential to be a valuable aid to radiologists in clinical practice, if certain technical problems can be overcome and if optimal operating points can be defined for clinical use.     

Application of artificial neural networks for quantitative analysis of image data in chest radiographs for detection of interstitial lung disease

The authors have developed an automated computeraided diagnostic (CAD) scheme by using artificial neural networks (ANNs) on quantitative analysis of image data. Three separate ANNs were applied for detection of interstitial disease on digitized chest images. The first ANN was trained with horizontal profiles in regions of interest (ROIs) selected from normal and abnormal chest radiographs for distinguishing between normal and abnormal patterns. For training and testing of the second ANN, the vertical output patterns obtained from the 1st ANN were used for each ROI. The output value of the second ANN was used to distinguish between normal and abnormal ROIs with interstitial infiltrates. If the ratio of the number of abnormal ROIs to the total number of all ROIs in a chest image was greater than a specified threshold level, the image was classified as abnormal. In addition, the third ANN was applied to distinguish between normal and abnormal chest images. The combination of the rule-based method and the third ANN also was applied to the classification between normal and abnormal chest images. The performance of the ANNs was evaluated by means of receiver operating characteristic (ROC) analysis. The average Az value (area under the ROC curve) for distinguishing between normal and abnormal cases was 0.976 +/- 0.012 for 100 chest radiographs that were not used in training of ANNs. The results indicate that the ANN trained with image data can learn some statistical properties associated with interstitial infiltrates in chest radiographs.     

Development of an improved CAD scheme for automated detection of lung nodules in digital chest images

Lung cancer is the leading cause of cancer deaths in men and women in the United States, with a 5-year survival rate of only about 13%. However, this survival rate can be improved to 47% if the disease is diagnosed and treated at an early stage. In this study, we developed an improved computer-aided diagnosis (CAD) scheme for the automated detection of lung nodules in digital chest images to assist radiologists, who could miss up to 30% of the actually positive cases in their daily practice. Two hundred PA chest radiographs, 100 normals and 100 abnormals, were used as the database for our study. The presence of nodules in the 100 abnormal cases was confirmed by two experienced radiologists on the basis of CT scans or radiographic follow-up. In our CAD scheme, nodule candidates were selected initially by multiple gray-level thresholding of the difference image (which corresponds to the subtraction of a signal-enhanced image and a signal-suppressed image) and then classified into six groups. A large number of false positives were eliminated by adaptive rule-based tests and an artificial neural network (ANN). The CAD scheme achieved, on average, a sensitivity of 70% with 1.7 false positives per chest image, a performance which was substantially better as compared with other studies. The CPU time for the processing of one chest image was about 20 seconds on an IBM RISC/6000 Powerstation 590. We believe that the CAD scheme with the current performance is ready for initial clinical evaluation.     

Measurement of absolute lung volumes by imaging techniques

In this paper, the techniques available for estimating total lung capacities from standard chest radiographs in children and infants as well as adults are reviewed. These techniques include manual measurements using ellipsoid and planimetry techniques as well as computerized systems. Techniques are also available for making radiographic lung volume measurements from portable chest radiographs. There are inadequate data in the literature to support recommending one specific technique over another. Though measurements of lung volumes by radiographic, plethysmographic, gas dilution or washout techniques result in remarkably similar mean results when groups of normal subjects are tested, in patients with disease, the results of these different basic measurement techniques can differ significantly. Computed tomographic and magnetic resonance techniques can also be used to measure absolute lung volumes and offer the theoretical advantages that the results in individual subjects are less affected by variances of thoracic shape than are measurements made using conventional chest radiographs.     

Pulmonary infections in HIV infected patients

We retrospectively reviewed causes, clinical presentations and chest radiographs of pulmonary infections in symptomatic HIV infected patients diagnosed in Srinagarind Hospital from February 1992 to 1994. We found 95 episodes of pulmonary infections in 88 HIV infected patients enrolled in our review. The three most common pathogens were Mycobacterium tuberculosis (37.2%), Pneumocystis carinii (23.8%), and Cryptococcus (15.2%). Coexistent pulmonary infections were seen in 10.5 per cent, mostly due to P. carinii and Cryptococcus neoformans. Extrapulmonary infections were also common, particularly with M. tuberculosis (49%) and C. neoformans (100%). The common clinical presentations were fever, dyspnea, and cough which frequency varied among the organisms. Chest radiographs were nonspecific, the most common finding was bilateral pulmonary infiltrates except that bacterial pneumonia usually presented with unilateral infiltrates. All patients wit PC had significant hypoxia (PaO2 < 70 mmHg). Due to nonspecific clinical and chest film presentations as well as frequent coinfections, definite diagnosis should be carried out in all HIV infected patients with pulmonary infections.     

Pulmonary toxicity of high-dose chemotherapy for breast cancer: a non-invasive approach to diagnosis and treatment

Drug-induced pulmonary toxicity is one of the most frequent non-hematologic toxicities in breast cancer patients receiving high-dose chemotherapy with cyclophosphamide, cisplatin and BCNU (CY/CDDP/BCNU). A non-invasive clinical scoring system was utilized in an attempt to diagnose and treat early lung toxicity in 64 consecutive breast cancer patients undergoing CY/CDDP/BCNU supported by peripheral blood progenitor cells. Following hospital discharge, patients who developed symptoms suggestive of lung toxicity were evaluated with physical examination, DLCO, 2-min walking oximetry and a chest radiograph. Clinically weighted scores were assigned as follows: crackles on lung exam, 2; decrease in corrected DLCO by > 10% from baseline, 3; decrease in O2 saturation by > or = 4% with a 2-min walk, 3; and interstitial infiltrates on chest radiograph, 3. Patients with scores > or = 6 were treated with prednisone (60 mg p.o. twice a day followed by a 2-month taper). Treatment was instituted in 37 patients (58%) a median of 56 days after high-dose chemotherapy. Steroid therapy was associated with rapid clinical improvement in most patients. No fatal complications or chronic pulmonary fibrosis was seen. This non-invasive clinical scoring system can be utilized as a model for the early diagnosis of lung toxicity. Further investigation is warranted for the development of preventative measures against this syndrome.     

Characterisation of a short interspersed repeat (Mermaid) that has family members on human chromosome 21 and elsewhere in the human genome

A 25-year-old man with hemophilia A who had received concentrated plasma and plasma factor VIII products since childhood presented with a productive cough and a fever. The CD4/CD8 ratio of peripheral lymphocyte subsets was very low and the serum was positive for anti-HIV antibodies. The chest roentgenogram showed bilateral multiple nodules with cavity formation. The patient underwent transbronchial lung biopsy, and the specimen obtained had Pneumocystic carinii organisms. The patient was treated with sulfamethoxazole and trimethoprim compounds, and with inhaled pentamizine. His condition improved. Patients with pulmonary pneumocystosis usually present with interstitial infiltrates spreading from the hilium to the periphery of the lungs, and nodular and cavitary lesions are unusual pulmonary radiographic findings in this condition.     

A case of lymphocytic interstitial pneumonia

A 56-year-old female was admitted on November 1995 to our hospital because of the abnormal shadow on her chest X-ray. Although the chest X ray film revealed diffuse reticulonodular shadows in the bilateral lung fields and right hilar lymphadenopathy, she had not any complaints. Furthermore, mediastinal lymphadenopathy and polyclonal hypergammaglobulinemia were noted. For a further examination, transcutaneous thoracoscopic lung biopsy was performed on August 1996. The lung specimens showed a interstitial infiltration of small lymphocytes exclusively around bronchioles. And the diagnosis of lymphocytic interstitial pneumonia (LIP) was made. She had been suffered from bronchial asthma for 27 years. This is the first report of LIP accompanied with bronchial asthma. Its relationship between LIP and bronchial asthma remains unclear. In the 2 years of follow-up, she remained asymptomatic with unchanged chest radiogram. And her pulmonary function was preserved for the 2 years. But lymphocytic interstitial pneumonia may induce malignant lymphoproliferative disease potentially, we should carefully follow up.     

Radiological evidence of involvement of dust exposure in pathogenesis of pulmonary alveolar proteinosis

A 52-year-old man was admitted because of increasing dyspnea on exersion and presence of pulmonary infiltrates. The patient had pulmonary tuberculosis at the age of 31, which resulted in volume loss and calcified foci in the upper lobe of his left lung. As a construction worker for more than 20 years, he had been exposed to inorganic dusts. Chest radiographs showed a symmetrical consolidation of infiltrates in both lungs with the exception of the left upper lobe, where no apparent infiltrates were shown. A computed tomographic scan of the chest revealed widely panlobular consolidation with the exception of the left upper lobe. A diagnosis of pulmonary alveolar proteinosis (PAP) was established by analysis of bronchoalveolar lavage fluid. Although the patient underwent segmental bronchoalveolar lavage four times under general anesthesia, he suffered frequent pulmonary infection and died two years after the onset his symptoms. Interestingly, the patient had a markedly narrowed orifice in the left upper lobe, as demonstrated by fiberoptic bronchoscopy. Chest radiographs of this lung field revealed no infiltrative shadows. These results suggest that some inhalative agent was involved in the pathogenesis of PAP in this case. In addition, significantly increased levels of KL-6 detected in both serum and bronchoalveolar lavage fluid were attributable to overproduction of KL-6 by Type II pneumocytes that had been stimulated or damaged by PAP.     

Comparison of an asymmetric screen-film combination with a conventional screen-film combination for chest radiography in 51 patients

Comparison is made between a new asymmetric screen-film combination and a conventional screen-film combination for use in chest radiography. Seven anatomical features were assessed by three consultant radiologists in each of 51 film pairs. A preference was indicated if one system better demonstrated a particular feature. Alternatively, no preference was indicated if the feature was equally demonstrated by both systems or not demonstrated at all. Any pathology incidentally noted which remained unchanged between the two films was localized to lung, mediastinum or bone and marked in the same way. The asymmetric high contrast system scored higher than the conventional system for demonstration of anatomy in both mediastinum and lungs, but no difference emerged between the two systems in the demonstration of pathology. The asymmetric screen-film system showed improved mediastinal and, to a lesser degree, improved lung detail. Further assessment in necessary to define any associated improvement in diagnostic yield.     

Steroid-responsive interstitial lung disease in patients receiving 2'-deoxy-5-fluorouridine-infusion chemotherapy. A report of three cases

BACKGROUND: Continuous infusion of 2'-deoxy-5-fluorouridine (FUdR) has shown promise in its activity against metastatic renal cell carcinoma. Its side-effect profile is dominated by gastrointestinal toxicity; there are no known adverse pulmonary reactions. To the authors' knowledge, this is the first report on the development of lung toxicity in three patients receiving FUdR-infusion chemotherapy for metastatic renal cell carcinoma. METHODS: The hospital charts of three patients presenting with pulmonary symptoms during FUdR chemotherapy were reviewed. A literature search was performed regarding FUdR-related pulmonary toxicity. RESULTS: Nonproductive cough, dyspnea, and fever appeared within the 10th chemotherapy cycle. Chest radiographs showed interstitial disease in each case, accompanied by a restrictive pattern by pulmonary-function testing. Lung biopsies were performed on two patients showing a pattern of interstitial inflammation. Discontinuing FUdR and instituting steroidal therapy invariably improved symptoms, as was evident by chest radiographs and pulmonary function tests. In one patient, resuming FUdR treatment resulted in a recurrence of the respiratory symptoms, which was controlled with an increased steroidal dose. All three patients required low dose steroids to maintain their baseline respiratory functions. CONCLUSIONS: 2'-deoxy-5-fluorouridine-related lung toxicity is an uncommon event and occurs late in the treatment course. It is rapidly symptomatic and responds readily to steroidal therapy.     

High-resolution CT of the lung: determination of the usefulness of CT scans obtained with the patient prone based on plain radiographic findings

OBJECTIVE: We assessed the usefulness of chest radiographs for predicting whether high-resolution CT scans obtained with the patient prone would be valuable in assessing suspected diffuse lung disease. MATERIALS AND METHODS: In 100 consecutive patients undergoing high-resolution CT, findings on plain chest radiographs were classified as normal, possibly abnormal, or abnormal. CT scans obtained with the patient supine were assessed for the presence and distribution of lung abnormalities without knowledge of the plain radiographic classification. A second review of the CT scans was done with equal numbers of scans obtained with the patient prone and with the patient supine. The usefulness of the CT scans obtained with the patient prone for detecting lung disease was determined and related to the plain radiographic classifications. RESULTS: High-resolution CT scans obtained with patients prone were helpful in excluding or confirming posterior lung abnormalities in 10 (28%) of 36 patients who had normal findings on chest radiographs, five (28%) of 18 patients who had possibly abnormal findings on chest radiographs, and only two (4%) of 46 patients who had abnormal findings on chest radiographs. The proportion of patients who benefited from high-resolution CT scans obtained with the patient prone was significantly lower among the patients with abnormal findings on chest radiographs than among the patients with normal (p = .008) or possibly abnormal (p = .02) findings on chest radiographs. The two patients with abnormal findings on radiographs in whom CT scans obtained with the patient prone were helpful had minimal radiographic abnormalities. CONCLUSION: In patients with suspected diffuse lung disease, obtaining high-resolution CT scans with the patient prone may be useful when chest radiographs show normal findings, possibly abnormal findings, or minimal abnormalities indicative of diffuse lung disease. However, such scans are of little value in patients whose radiographs show abnormalities indicative of diffuse lung disease.     

Palisaded encapsulated neuroma of the nasal fossa

The aim of the study was to assess the potential application of teleradiology in the neonatal intensive care unit (NICU) by ascertaining whether any decrease in conspicuity of anatomic detail or interventional devices in the chest radiographs of premature infants is caused by picture archiving and communication system (PACS)-based soft copy interpretation of 10 : 1 compressed images. One hundred digital chest radiographs of low-birthweight infants were obtained in the NICU using a storage phosphor system. Laser-printed images were interpreted and the data set for each radiograph was then irreversibly compressed by a 10 : 1 ratio. Four radiologists with extensive PACS experience used a five-point grading system to score laser-printed hard copy images for the visibility of six parameters of anatomic landmarks and interventional devices in the chest. Compressed soft copy images displayed on 2K PACS workstation were subsequently scored using the same approach. Statistical manipulation demonstrated no loss of anatomic detail in five of the six parameters scored, with minimal difference in one landmark, the retrocardiac lung assessment. While further study is required to assess the clinical impact of the variance noted when evaluating lung parameters, the preservation or improvement of information in the remaining parameters following irreversible compression and soft copy interpretation is promising for the potential use of teleradiology in this population.     

Mottle on computed radiographs of the chest in pediatric patients

PURPOSE: To investigate the relationship between radiation exposure and perceived mottle at bedside pediatric chest examinations performed with screen-film and computed radiographic techniques. MATERIALS AND METHODS: In a pediatric intensive care unit, chest radiographs were obtained with both computed radiography (60 radiographs) and a 600-speed screen-film system (14 radiographs). The relative radiation exposure was estimated by using the sensitivity value obtained in the processing of each computed radiograph. Five radiologists assessed the mottle present in the computed radiographs and screen-film images. RESULTS: For computed radiographs, the perceived level of mottle was inversely related to radiation exposure. For the same radiation exposure, the perceived mottle on computed radiographs was significantly higher than that on screen-film images (P < .001 for small cassettes; P < .01 for large cassettes). CONCLUSION: Pediatric computed radiography of the chest requires approximately twice the exposure of a 600-speed screen-film system to attain the same level of mottle.     

The hepatopulmonary syndrome: radiologic findings in 10 patients

OBJECTIVE: The purpose of this study was to review the radiologic manifestations of the hepatopulmonary syndrome. MATERIALS AND METHODS: We retrospectively reviewed clinical records, chest radiographs, 99m Tc-macroaggregated albumin (MAA) perfusion lung scans, chest CT scans, and pulmonary angiograms of 10 patients with proven hepatopulmonary syndrome. RESULTS: Chest radiographs showed basilar, medium-sized (1.5-3.0 mm) nodular or reticulonodular opacities in all cases. CT was done in eight cases and showed basilar dilatation of lung vessels with a larger than normal number of visible branches. The vascular basis for these opacities was best appreciated on conventional CT scans of 10-mm sections. No individual arteriovenous malformations were seen on CT scans. High-resolution CT scans showed no evidence of interstitial fibrosis. 99mTc-MAA perfusion lung imaging, done in seven patients, showed pulmonary arteriovenous shunting in five. Contrast echocardiography confirmed intrapulmonary shunting in these five patients. Pulmonary angiography, done in four cases, showed subtle distal vascular dilatation in two and moderate dilatation with early venous filling in two but did not reveal any individual arteriovenous malformations. CONCLUSION: Chest radiographs in hepatopulmonary syndrome usually show bibasilar nodular or reticulonodular opacities. Conventional CT shows that these opacities represent dilated lung vessels. High-resolution CT is useful in excluding pulmonary fibrosis or emphysema as the cause of these opacities. 99mTc-MMA perfusion imaging or contrast echocardiography can be used to confirm intrapulmonary arteriovenous shunting.     

HMG-CoA reductase inhibitor and risk of stroke

A 75-year-old-man who had been occupationally exposed to asbestos over several decades was admitted complaining of dry cough and mild exertional dyspnea. Chest X-ray films revealed the presence of bilateral infiltrates. An open biopsy showed the lung pathology to be desquamative interstitial pneumonitis (DIP), and detected a calcified plaque of the left parietal pleura at cost-phrenic sulcus, which on microscopic inspection demonstrated thin needle-like structures suggestive of asbestos particles. A hormonal examination showed decreased levels of tri-iodothyronine and tetraiodothyronine and an increased level of thyroid stimulating hormone. Additionally, a positive microsome test indicated autoimmune hypothyroidism. A serological study was positive for anti-nuclear antibody and direct Coombs, and showed heightened levels of IgG. The patient was placed on oral prednisolone therapy; one month later, his symptoms had subsided, and his lung function and chest x-ray findings had improved significantly. In addition, the abnormal values for autoimmune and thyroid function eventually returned to normal ranges. These findings suggest that DIP and humoral immune dysfunction were caused by asbestos exposure, and responded well to steroid treatment.     

The diagnostic accuracy of high-resolution computed tomography in diffuse infiltrative lung diseases

The purpose of this study was to evaluate the role of high-resolution computed tomography (HRCT) in the clinical diagnosis of diffuse infiltrative lung disease (DILD). Diagnostic accuracy was compared using both chest radiography and HRCT. One hundred thirty-four cases of DILD, representing 21 different diseases, were selected for study, and the disease state was confirmed either histologically or microbiologically. The HRCT images and chest radiographs, available in all cases, were reviewed separately and in random order by 20 physicians who were provided only with information on each patient's age and sex. Overall, a correct first-choice diagnosis was made in 38 percent using radiographs and in 46 percent using HRCT images (p < 0.01). The correct diagnosis was among the top three choices in 49 percent when chest radiographs were used, and in 59 percent when HRCT images were viewed (p < 0.01). The correct first-choice diagnosis increased remarkably when the HRCT was used in usual interstitial pneumonia, sarcoidosis, alveolar proteinosis, bronchiolitis obliterans organizing pneumonia, hypersensitivity pneumonitis, and pulmonary lymphangiomyomatosis. High-resolution computed tomography was confirmed to be superior to conventional radiography in the accurate diagnosis of DILD in clinical practice.     

Bronchiolitis obliterans with organizing pneumonia in a patient treated with amiodarone]

Bronchiolitis obliterans organizing pneumonia (BOOP) is a well-defined clinicopathological entity. The aetiology of BOOP is generally unknown, although it has been associated with specific diseases or various pharmaceutical drugs. The amiodarone is one of them. We report a patient with BOOP secondary to amiodarone therapy, who presented with cough, fever and sputum production, dyspnoea and night sweats lasting for two months. A chest radiograph showed bilateral patchy and interstitial infiltrates. Lymphocyte phenotyping of bronchoalveolar lavage fluid showed decreased ratio of CD4+:CD8+ lymphocytes. Transbronchial lung biopsy established the diagnosis of BOOP. After stopping amiodarone therapy, symptoms disappeared and the chest radiograph remained normal within two months.