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Biomedical subjects

T Johkoh

Publications and source records attributed to T Johkoh.

At least 55 records · Page 3Linked to original sources
PubMed1996

High-resolution CT findings of lung disease in patients with polymyositis and dermatomyositis.

The purpose of this study was to determine the type and distribution of interstitial lung disease seen in patients with polymyositis and dermatomyositis, using high-resolution computed tomography (HRCT). The presence and distribution of high-resolution CT findings were retrospectively evaluated in 25 patients with polymyositis/dermatiomyositis. In 14 patients, a pathological diagnosis of pulmonary disease was obtained. Three lung specimens were also studied. Results showed that 23 patients had abnormal HRCT showing the following abnormalities: ground glass opacities (92%), linear opacities (92%), irregular interfaces (88%), airspace consolidation (52%), parenchymal micronodules (28%), and honeycombing (16%). A relatively high prevalence of airspace consolidation (52%) and a low prevalence of honeycombing (16%) were observed. Two patients with extensive consolidation proved to have diffuse alveolar damage; eight patients with either subpleural band-like opacities (n = 5) and/or airspace consolidation (n = 7) had bronchiolitis obliterans organizing pneumonia; four patients with honeycombing had usual interstitial pneumonitis. We conclude that HRCT findings in patients with polymyositis/dermatomyositis are nonspecific. However, a high prevalence of airspace consolidation and a low prevalence of honeycombing were observed. Predominant HRCT patterns are suggestive of the pathologic processes occurring in polymyositis/dermatomyositis.

Adrenal Cortex Hormones↗
PubMed1996

Dynamic range control processing of digital chest images. A clinical evaluation.

PURPOSE: The clinical usefulness of an advanced image-processing system called "dynamic range control processing" was investigated, with which selected parts of the dynamic range of digital chest images could be controlled. MATERIAL AND METHODS: A comparative study of 3 different post-processed formats of storage phosphor (SR) images was performed in 35 patients with abnormalities in the chest. The 3 formats were SR images with standard mode (SR-standard), SR images with strong edge-enhancement (SR-enhanced), and dynamic range controlled SR images (SR-controlled). RESULTS: For lung abnormalities, there was no difference among the 3 SR image formats. For normal mediastinal structures and lung abnormalities covered by the heart or diaphragm, SR-controlled and SR-enhanced images were significantly superior to SR-standard images, while no difference was found between SR-controlled and SR-enhanced images except for the trachea and bony structures. CONCLUSION: Dynamic range control processing appears to be a useful method for displaying SR chest images with an extremely wide dynamic range.

Adolescent↗
PubMed1996

Detection of subtle interstitial abnormalities of the lungs on digitized chest radiographs: acceptable data compression ratios.

OBJECTIVE: To determine acceptable compression ratios for digital radiography, we evaluated the effect of data compression on the detection of subtle interstitial lung abnormalities using digitized chest radiographs. MATERIALS AND METHODS: Screen-film chest radiographs of 38 patients with subtle interstitial lung abnormalities and 40 patients with normal lung parenchyma were digitized (spatial resolution, 0.175 mm; 2000 x 2000 pixels; 10 bits per pixel) and compressed with the discrete cosine transform method at ratios of 10:1, 20:1, and 30:1. Five chest radiologists and five radiology residents examined the uncompressed and compressed digital images and rates the presence of interstitial lung abnormalities with a five-level scale of confidence. Results were analyzed by receiver operating characteristic methods. RESULTS: Overall, the interpretation of images with a compression ratio of 30:1 was significantly less accurate than that of uncompressed images (p < .05). For the five chest radiologists, interpretation of images with a compression ratio of 20:1 or 30:1 was significantly less accurate than that of uncompressed images (p < .05). However, for the five residents, no significant difference between interpretations of compressed and uncompressed images was noted (p > or = .05). CONCLUSION: These results suggest that a 10:1 data compression ratio does not influence the detection of subtle interstitial lung abnormalities. However, information that is lost with a 20:1 data compression ratio might be essential for interpretation by experienced chest radiologists.

Adult↗
PubMed1995

Interpretation of subtle interstitial chest abnormalities: conventional radiography versus high-resolution storage-phosphor radiography--a preliminary study.

To evaluate the reliability of digital chest radiography in diagnosing subtle interstitial lung abnormalities, we performed several clinical studies including a comparison of conventional screen-film radiography and storage-phosphor radiography (2 K x 2 K pixels, 10 bit), and a comparison of conventional screen-film radiography and film-digitized radiography (2 K x 2 K pixels, 10 bit). From these previous studies, a spatial resolution of 0.2-mm pixel size was considered inadequate to diagnose subtle interstitial lung diseases. Under these circumstances, the newly developed Fuji Computed Radiography system (FCR 9000; Fuji Photo Film, Tokyo, Japan) has recently become available. This system provides 0.1-mm pixel size (4 K x 5 K pixels, 10-bit depth) and life-size hard copies (14 x 17 inches). To evaluate the reliability of new high-resolution storage-phosphor radiography (FCR 9000) in diagnosing simulated subtle interstitial abnormalities (including simulated lines, micronodules, and groundglass opacities), the differences among radiologists in interpreting conventional screen-film radiographs and life-size high-resolution storage-phosphor radiographs were studied. Observation was made by eight experienced chest radiologists and receiver-operating characteristic (ROC) analysis was performed. There was no significant difference in detecting in subtle simulated interstitial abnormalities between conventional film-screen radiography and high-resolution storage-phosphor radiography. For all three types of abnormalities, there was no significant difference between conventional and storage-phosphor radiography. In conclusion, the high-resolution storage-phosphor chest radiography (0.1-mm pixel size, 10-bit depth) may be substituted for conventional chest radiography in the detection of subtle interstitial abnormalities.

Data Display↗
PubMed1994

High-resolution CT and pulmonary function tests in collagen vascular disease: comparison with idiopathic pulmonary fibrosis.

To estimate whether the lung abnormalities seen in collagen vascular diseases (CVD) were similar or distinct to those seen in idiopathic pulmonary fibrosis (IPF), and to ascertain whether the extent of the abnormalities on high-resolution CT (HRCT) correlated with pulmonary function, we reviewed HRCT findings and pulmonary function test results of 64 patients with either CVD (n = 55) or IPF (n = 9). Response to corticosteroid treatment was also evaluated in 20 of the 64. High incidence of honeycomb lesion was observed in IPF (9/9, 100%) and in progressive systemic sclerosis (PSS) (11/14, 79%). CVD, except for PSS, had a low incidence of honeycomb lesion (27%). On the other hand, incidence of ground-glass shadow in CVD (47/55, 85%) was the same as that in IPF (8/9, 89%). Diffusing capacity significantly correlated with the extent of all parenchymal abnormalities in all CVD and IPF, with honeycomb lesion in PSS, and with ground-glass shadow or air-space consolidation in CVD except for PSS (r < -0.7, P < 0.001). In all 15 cases in which corticosteroid therapy was effective, no honeycomb lesions were seen. Collagen vascular disease, except for PSS, had a different pattern of disease than IPF. The morphologic changes seen on HRCT correlated well with pulmonary function in CVD.

Collagen Diseases↗
PubMed1994

Interpretation of subtle interstitial lung abnormalities: conventional versus film-digitized radiography.

PURPOSE: To evaluate the reliability of film-digitized radiography in detection of subtle interstitial lung abnormalities. MATERIALS AND METHODS: The differences in interpretation of conventional screen-film (SF) and film-digitized (FD) radiographs obtained in 80 patients were studied. Forty patients with subtle interstitial lung abnormalities and 40 patients with no lung abnormalities were selected. SF radiographs of all patients were digitized (spatial resolution, 0.175 mm; 2,000 x 2,000 pixels; 10 bits). Five chest radiologists and five residents evaluated the images with a five-level scale of confidence. Results were evaluated with receiver operating characteristic techniques. RESULTS: For the entire group, no statistically significant differences in performance were found between SF and FD radiographs. Chest radiologists performed better on SF radiographs (P = .003). For residents, no statistically significant differences were observed between the modalities. CONCLUSION: FD radiographs may be inadequate compared with SF radiographs in the diagnosis of subtle interstitial lung abnormalities.

Adult↗
PubMed1994

Metastatic pulmonary calcification in patients with hypercalcemia: findings on chest radiographs and CT scans.

OBJECTIVE: The objective of this study was to characterize the findings on chest radiographs and CT scans in patients with metastatic pulmonary calcification due to hypercalcemia. MATERIALS AND METHODS: The chest radiographs and CT scans of seven patients with biopsy-proved metastatic pulmonary calcification were reviewed by two observers. Metastatic calcification was due to chronic renal failure (n = 4), T-cell leukemia (n = 1), multiple endocrine neoplasia type I syndrome (n = 1), and idiopathic hypercalcemia (n = 1). RESULTS: Numerous nodular opacities measuring 3-10 mm in diameter were seen on the chest radiographs in five cases, and patchy areas of parenchymal opacification were seen in two cases. Calcification of the nodules was evident in two cases. On CT scans, pulmonary nodules were present in all seven cases. These nodules were predominant in the upper lung zone in three cases, were diffuse in three cases, and were predominant in the lower lung zone in one case. Calcification of the nodules was evident on the CT scans in four of the seven cases, and calcification of vessels in the chest wall was evident in six of seven cases. Other findings on CT scans included diffuse areas of ground-glass attenuation (n = 3) and patchy consolidation (n = 2). CONCLUSION: Numerous small nodules are the most common finding on the chest radiographs of patients with metastatic pulmonary calcification. The calcific nature of the nodules is seldom obvious, however. Pulmonary nodules are also the most common finding on CT scans, where the calcific nature of the nodules is more readily apparent. Additionally, calcification is often seen in the vessels of the chest wall on CT scans. The combination of calcified nodules and calcified vessels in the chest wall on CT scans may be characteristic.

Adult↗
PubMed1993

Focal organizing pneumonia: CT appearance.

PURPOSE: To clarify the computed tomographic (CT) features of focal organizing pneumonia. MATERIALS AND METHODS: The authors retrospectively studied CT scans of 18 patients with histologically proved focal organizing pneumonia. Chest radiographs in all 18 patients suggested bronchogenic carcinoma. RESULTS: Seventeen of the 18 lesions (94%) had an irregular margin, 10 (56%) had satellite lesions, nine (50%) had a pleural tag, and nine (50%) had an air bronchogram. The pneumonia could be classified into three types: Type A (n = 5) was a small round mass (pleural tag, n = 4). Type B (n = 7) was an oval mass with broad contact with the pleura (satellite lesions and convergence of peripheral vessels, n = 6). Type C (n = 6) was an oval mass along the bronchovascular bundle (satellite lesions, n = 3; pleural tag, n = 4). CONCLUSION: The CT features of focal organizing pneumonia show wide variation, and some type B and C lesions are suggestive of benign lesions. However, other lesions may be difficult to differentiate from bronchogenic carcinoma even with CT.

Adult↗
PubMed1993

Mechanism of gravity-dependent atelectasis. Analysis by nonradioactive xenon-enhanced dynamic computed tomography.

RATIONALE AND OBJECTIVES: The physiologic mechanism of gravity-dependent atelectasis (GDA), a common finding identified during anesthesia, is not well understood. The purpose of this study was to determine whether an inherent reduction in alveolar volume or a reduction in alveolar ventilation is the more important causative factor for the development of GDA in an experimental animal model. METHODS: After uniform reduction of lung volume in ten rabbits by artificially induced pneumoperitoneum, dynamic inhalation computed tomography (CT) was performed using 50% nonradioactive xenon in oxygen. Time-CT attenuation value curves were fitted to an exponential function, CT value = a - b x e(-kt), and K value, which is proportional to the alveolar ventilation/alveolar volume ratio, was calculated by regression analysis. RESULTS: Gravity-dependent atelectasis occurred only in 5 of 10 rabbits. In this group, K values in the dorsal regions increased before the appearance of GDA. No significant change in K values in the ventral regions was observed. CONCLUSION: One mechanism of GDA may be a preferential reduction in alveolar volume without small airway collapse rather than alveolar volume loss secondary to decreased ventilation.

Animals↗
PubMed1992

CT findings in lymphangitic carcinomatosis of the lung: correlation with histologic findings and pulmonary function tests.

The purpose of this study was to analyze the CT findings in lymphangitic carcinomatosis and to determine how the abnormalities seen on CT correlated with histologic findings and the results of pulmonary function tests. Accordingly, we reviewed CT findings in 20 proved cases and correlated them with histologic findings and with results of pulmonary function tests (available in 11). Special attention was given to the extent and degree of thickening of the peripheral and/or axial interstitium as seen on CT. In 15 of 20 patients, CT scans showed marked thickening of axial interstitium and subtle or no thickening of peripheral interstitium (four diffuse and 11 localized). In three cases, CT showed marked thickening of both axial and peripheral interstitium (two diffuse and one localized). In two cases, CT showed marked thickening of peripheral interstitium and subtle or no thickening of axial interstitium (one diffuse and one localized). These CT findings correlated with the pathologic findings. Marked impairment of vital capacity and alveolar-arterial oxygen gradient was observed in three patients (one with diffuse and peripheral interstitial thickening and two with diffuse and both peripheral and axial interstitial thickening). We conclude that CT findings in patients with lymphangitic carcinomatosis are variable and that marked impairment of pulmonary function occurs in patients with diffuse and peripheral interstitial thickening. Marked impairment of pulmonary function can be predicted from CT findings.

Adult↗
PubMed1992

CT appearance of pulmonary tuberculosis in diabetic and immunocompromised patients: comparison with patients who had no underlying disease.

OBJECTIVE: It has been stated, but not adequately assessed, that pulmonary tuberculosis in diabetic or immunocompromised patients often has an atypical pattern and distribution. To evaluate the CT features of pulmonary tuberculosis in diabetic or immunocompromised patients compared with patients without underlying disease, we performed this retrospective study. MATERIALS AND METHODS: We reviewed conventional CT scans (n = 100) and high-resolution CT scans (n = 16) of the chest in 110 adult patients with active postprimary tuberculosis. Seventy-one patients had no underlying disease, 31 had diabetes mellitus, and eight were immunocompromised. RESULTS: In patients who had no underlying disease, 44 had nodular opacities, 11 had consolidation, and 13 had consolidation with associated loss of volume. Characteristic features of tuberculosis in this group of patients included segmental distribution (97%), satellite lesions (93%), single cavity within any given lesion (95%), and tendency toward architectural distortion and loss of volume. In diabetic and immunocompromised patients, 15 had nodular opacities, seven had consolidation, and 15 had consolidation with associated loss of volume. Diabetic and immunocompromised patients had a high prevalence of nonsegmental distribution (30%) and multiple small cavities within any given lesion (44%). Unusual localization of tuberculosis, including disease confined to the basal segments of the lower lobes, anterior segment of the upper lobes, or right middle lobe, occurred equally in both groups (17% and 18%). CONCLUSION: We conclude that diabetic and immunocompromised patients have a higher prevalence of multiple cavities within any given lesion (p < .01) and of nonsegmental distribution (p < .01) than do patients without underlying disease.

Adult↗
PubMed1991

[Chest radiograph of foreign bodies in the tracheobronchial tree].

Chest radiographs in 14 children with foreign bodies in the tracheobronchial trees were evaluated retrospectively. The most common causative materials were nuts, and both main bronchi were most commonly involved. The initial chest radiographs that were used for analysis were obtained one hour to 50 days after aspiration or onset of symptoms. Of the nine cases in which chest radiographs were taken within 7 hours after aspiration, six showed hyperlucency with (three cases) or without overinflation (three cases) in the affected lungs, and the other three showed normal chest radiographs. Two patients had indeterminate diagnoses on chest radiographs at inspiration: one patient underwent chest radiographs at expiration and the other underwent fluoroscopy. Air-trapping was demonstrated in both patients. Of another five cases in which chest radiographs were taken 18 hours after aspiration of a foreign body, three cases showed atelectasis or consolidation and the other two showed hyperlucent lung. From these observations, hyperlucent lung indicates an early stage of the disorder while atelectasis or consolidation indicates a fairly advanced stage. In patients with clinically suspected foreign bodies, we advocate that additional examinations be performed to establish a final diagnosis, even when chest radiographs are normal or indeterminate.

Bronchi↗
PubMed1991

CT findings of endobronchial metastasis.

One hundred and sixty-one patients with pulmonary metastases were studied with CT. Six of them proved to have endobronchial (intraluminal) metastatic lesions by bronchoscopy. Retrospective analysis of the CT studies showed obstruction and/or narrowing of the bronchi in 5 cases while no lesion was observed in one patient. Although CT can not always demonstrate intraluminal lesions, it should be performed when an endobronchial metastasis from extrathoracic malignancy is seen by bronchoscopy because it will show hilar or mediastinal lymphadenopathy, or single or multiple pulmonary metastases other than the endobronchial lesion.

Adult↗
PubMedDate not supplied

Head and neck carcinoma: detection of extraorgan spread with MR imaging and CT.

A retrospective analysis of the Magnetic resonance (MR) and CT findings in 18 untreated carcinomas of the oral cavity (7), oropharynx (2), hypopharynx (7), and larynx (2) was performed to assess the accuracy in evaluating extraorgan tumor spread and nodal involvement. Surgical and pathologic correlation was available for 13 primary tumors and nodal status was analyzed in 18. Nine primary tumors had extraorgan extension. MR had a tendency to be superior to CT in predicting tumor invasion of the cartilage and muscle. Sensitivity, specificity and accuracy for extraorgan spread of primary tumors were 89%, 100% and 92%, respectively, for MR and 78%, 75% and 77% for CT. Accuracy for nodal classification (83%) and carotid invasion (94%) of MR was equal to that of CT. CT was more sensitive than MR for demonstrating necrosis within the nodes and vice versa for detecting retropharyngeal nodes. MR imaging is a useful radiologic modality in evaluating extraorgan tumor spread and nodal levels of the head and neck carcinomas.

Adult↗
PubMedDate not supplied

CT and MR appearances of parotid pseudotumors in Sjögren syndrome.

The radiologic findings in eight patients with parotid pseudotumors associated with Sjögren syndrome (CT in eight; MRI in two) were retrospectively analyzed and compared with the findings in three cases with malignant lymphomas. Diagnosis of pseudotumor was obtained by surgery in six cases and by fine-needle aspiration biopsy and radiologic follow-up in the remaining cases. Six cases (75%) had advanced disease and the remaining had early disease. Both solid (75%) and cystic (38%) masses were seen in the patients with pseudotumors. The masses were solitary in 25%, multiple in 75%, unilateral in 25%, and bilateral in 75%. All three lymphomas were solid masses. The lymphomatous masses were not reliably distinguished from the solid pseudotumors.

Adult↗
PubMedDate not supplied

CT findings in "pseudoalveolar" sarcoidosis.

To determine the specific high resolution CT (HRCT) features for "pseudoalveolar" sarcoidosis, we reviewed HRCT of 10 patients with pathologically proven sarcoidosis. On HRCT the lesions of pseudoalveolar sarcoidosis were shown as homogeneous or inhomogeneous opacities 1-4 cm in diameter located either along the bronchovascular bundles or in the lung periphery adjacent to the pleural surface. The margin was irregular, and numerous nodules 1-2 mm in diameter were observed in the surrounding lung. Air bronchograms were observed in 6 patients. In addition to these lesions, other CT abnormalities such as nodules, groundglass opacities, thickened bronchovascular bundles, and interlobular septa were found in all 10 cases. Good response of pseudoalveolar sarcoid lesions to administration of corticosteroid was observed in all three cases in which follow-up CT was available.

Adult↗
PubMedDate not supplied

Fractal analysis for classification of ground-glass opacity on high-resolution CT: an in vitro study.

PURPOSE: Fractal analysis based on the fractional Brownian motion model was applied ground-glass opacity on high-resolution CT (HRCT) to investigate its usefulness in distinguishing ground-glass opacity caused by nonfibrotic disease processes and that caused by fibrotic disease processes, confirming pathology. METHOD: Twenty-one postmortem lungs inflated and fixed by Heitzman's method were evaluated. By correlating HRCT and pathology, the lungs were classified into nonfibrotic disease processes and fibrotic disease processes. Fractal analysis based on the fractional Brownian motion model provides the parameter H, which is a statistical measure related to the psychophysical perception of roughness. For regions of interest positioned over ground-glass opacities on HRCT, conventional statistics (mean value and SD) and the estimated H values were calculated using a workstation. RESULTS: Pathologically, 10 lung specimens were categorized as nonfibrotic disease processes and 11 as fibrotic disease processes. Whereas the conventional statistics had considerable overlap in two disease processes, the overlapping was drastically reduced in the H values. The H values of fibrotic disease processes (mean +/- SD, 0.423 +/- 0.064) were significantly greater than those of nonfibrotic disease processes (0.297 +/- 0.036) (p < 0.001). CONCLUSION: Fractal analysis based on the fractional Brownian motion model may provide a new promising scheme for assessing ground-glass opacity on HRCT caused by either nonfibrotic or fibrotic disease processes.

Fractals↗