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.     

High-resolution computer tomography of diffuse infiltrative lung diseases

During a period of 17 months, a total of 101 patients were examined by high resolution computed tomography (HRCT) whose minor focal changes revealed by chest X-ray raised the suspicion of diffuse infiltrative pulmonary disease. The disease of the interstitium was primarily caused by idiopathic pulmonary fibrosis (19%), autoimmune disease (18%), Boeck sarcoidosis (18%) as well as by specific (16%) and aspecific inflammation (12%). HRCT disclosed reticular (61%), nodular (55%), ground-glass opacity-like (48%), emphysematous (33%) and ring-like changes (17%). Also transbronchial excision was performed in 51 patients the results of which were compared to the changes observed during HRCT. Concerning fibrosis and inflammation, HRCT and histological analysis showed identical results in 70%. According to the authors observations, this technique is suitable for detection of fairly fine fibrotic, empysematous and inflammatory signs and for defining the activity of the individual disease as also for the selection of the optimal site of transbronchial excision. HRCT is a useful investigative method both for diagnosing diffuse infiltrative pulmonary disease as well as in following up the effectiveness of treatment.     

Imaging the ''dirty lung''--has high resolution computed tomography cleared the smoke?

RATIONALE AND OBJECTIVES: The objective was to analyze if liver enhancement with mangafodipir trisodium was influenced by liver cirrhosis. METHODS: Eighty patients (49 with cirrhotic and 31 with noncirrhotic livers) were studied with spin-echo and spoiled gradient-echo T1-weighted images, before and after administration of mangafodipir trisodium. Hepatic insufficiency was assessed using the Child classification. Image analysis was performed both qualitatively and quantitatively. RESULTS: Noncirrhotic livers enhanced homogeneously but 37% of cirrhotic livers did not; the difference was significant. Areas corresponding to collapsed fibrous zones enhanced less than the rest of the parenchyma; areas of regenerating nodular zones enhanced more. Signal-to-noise ratios were significantly less for cirrhotic livers on postcontrast spoiled gradient-echo images. Cirrhotic livers had significantly lower relative enhancement ratios than noncirrhotic ones. The Child index and aspartate aminotransferase values were statistically related to the enhancement ratio. CONCLUSIONS: Mangafodipir trisodium enhancement in cirrhotic livers is related to necrosis and regeneration of the hepatocytes. Cirrhotic livers enhanced less than noncirrhotic ones.     

High-resolution computed tomography sampling for detection of asbestos-related lung disease

RATIONALE AND OBJECTIVES: We determined whether a limited number of high-resolution computed tomography (HRCT) scans will effectively screen for interstitial lung disease (ILD) in a population of individuals exposed to asbestos. METHODS: We retrospectively reviewed the computed tomography studies of 49 patients exposed to asbestos. HRCT in the supine and prone positions had been performed at specifically preselected levels. Two teams of thoracic radiologists evaluated, on separate occasions: (1) all images, (2) prone images only, and (3) a single prone image through the lung bases for the presence of diffuse ILD. RESULTS: A relatively high level of accuracy was obtained with a single prone scan. However, improvement to 95% or better was found when additional prone images were used. CONCLUSION: A screening study for ILD, in this case patients exposed to asbestos, may be performed by preselected prone HRCT images only. The ease and decreased time of performing the procedure make screening relatively large patient groups for ILD more feasible.     

Hypofrontality revisited: a high resolution single photon emission computed tomography study in schizophrenia

Hypofrontality or reduced activity in the prefrontal cortex, measured as reduced frontal perfusion or glucose uptake, has gained the status of an established finding in the medical literature on schizophrenia. Many relevant studies, however, have potential sources of bias, such as small subject numbers, or unreliable performance of activation tasks by the patients during the scanning procedure. Seventy patients with non-affective and non-organic psychoses were recruited--most qualifying for DSM III-R schizophrenia or schizophreniform psychosis (n = 60)--together with 20 healthy volunteers. They underwent single photon emission computed tomography with 99mTc-exametazime, carried out at rest. Tracer uptake was normalised to the occipital cortex. Group differences in tracer uptake were predicted in anterior regions of interest (prefrontal cortex and mesial frontal/cingulate cortex). Actively psychotic (including schizophrenic) patients not taking any drugs showed increased uptake in the prefrontal cortex. Reduced tracer uptake occurred in the mesial frontal cortex of schizophrenic patients, particularly if they were taking drugs. Relatively increased prefrontal tracer uptake associated with relatively decreased mesial frontal uptake characterised the patients in comparison with the controls. Generalised hypofrontality is, therefore, not a feature of schizophrenic patients at rest whether taking drugs or not.     

Assessment of complications in patients with lung transplantation with high resolution computerized tomography

INTRODUCTION: High Resolution Computed Tomography (HRCT) has been used by many authors to study the early complications of lung transplantation. Bronchoscopy, transbronchial biopsy and the clinical parameters are the tools of choice to diagnose such complications; HRCT showed excellent sensitivity (100%) and good specificity (93%) especially in detecting bronchial stenoses. We report the preliminary results of HRCT in detecting early/late complications in lung transplant recipients. MATERIAL AND METHODS: Sixteen lung transplant recipients (5 single and 11 double transplants) were examined with HRCT at the Servizio Speciale Diagnostica V of "La Sapienza" University (Rome, Italy). The CT findings were compared with the results of bronchoscopy and respiratory function tests. The patients (8 men and 8 women; age range: 18-57 years, mean: 37.5) had cystic fibrosis (9), emphysema (3), alpha-1-antitrypsin deficiency (1), idiopathic pulmonary fibrosis (2), and bronchiectasis (1). RESULTS AND DISCUSSION: During the follow-up, one patient died of pulmonary edema. CT findings were normal in 3 patients and mild pleural effusion was seen in 2. The other HRCT findings were: bronchial stenosis in 5 cases (which was bilateral in 1) and bronchial dehiscence in 1 patient; four cases of infection (1 CMV, 1 aspecific bacterial pneumonia, 1 Chlamydia psittacea and 1 Aspergillosis) and one of brochiolitis obliterans. A patient was treated for acute and one for chronic rejection. A CMV infection involved only the native lung in a patient. CT is easy to perform and a repeatable and well-tolerated tool with high sensitivity (100%) and good specificity (93%) in the early diagnosis of complications, particularly bronchial stenoses, which complications are often missed at bronchoscopy or clinically silent. CT should be always performed before bronchoscopy because it can provide valuable information for bronchoscopy targeting. CONCLUSIONS: In agreement with other authors we consider HRCT a very useful tool in the early diagnosis of the complications following lung transplantation.     

Usefulness of computed tomography and scintigraphy in diagnosis of emphysematous bullae in the lung

The x-ray examinations usually do not reveal morbid changes after lung expansion in the treatment of spontaneous pneumothorax. In our observation computed tomography (CT) and scintigraphy enable not only the exact determination of the extent of changes but also they disclose bullae invisible in conventional chest radiographs. 15 patients with cured spontaneous pneumothorax and 10 patients with radiographic evidence of a bulla or bullae were examined. CT scans showed bullae from 3 to 18 cm in diameter involving predominantly the upper lobes. 4 patients had additionally subpleural or intraparenchymal bullae of various degrees. In all patients with cured spontaneous pneumothorax, CT scans revealed intraparenchymal bullae, and in 6 cases bilateral intraparenchymal bullae were revealed. Only in sites of large bullae, no isotopic marker or its low elimination was shown in perfusion and inhalation scintigraphy. 10 patients with giant bullous emphysema were operated; in 6 patients enucleation of bullae, in 3 lobectomy and in one patient bullectomy were performed. CONCLUSION: CT is a method of choice in the diagnosis of lung emphysematous bullae and it enables the detection of the changes undetectable in chest radiographs. Perfusion and inhalation scintigraphy is helpful in the diagnosis of large emphysematous bullae and postoperative follow-up examination.     

Efficiency of computed tomography in diagnosis of silicotuberculosis

Seventy-five newborns from multiple pregnancies with very low and extremely low birth weight are studied. 94% of the infants under 1000 g and 66% of those above 1000 g are born by vaginal way. Intrapartal asphyxia develop most often the second twins with birth weight under 1000 g--64.7%. These are the infants with higher morbidity: RDS--56.5%, IVH--100%. The survival rate of the twins of this group is notably lower than that of the infants from singleton pregnancies with equal weight and gestational age: 12.1% under 1000 g and 69% above 1000 g, against 38.3% and 77.9% respectively.     

The recording of parenchymal lung changes in smokers by high-resolution computed tomography

Using Caco-2BBe monolayers as a model of the intestinal epithelium, we tested the hypothesis that reactive oxygen metabolites contribute to lactic acid-induced hyperpermeability. Compared to monolayers incubated at normal pH (i.e., 7.4) monolayers incubated in medium titrated to extracellular pH (pHo) 5.0 with 10 mM lactic acid demonstrated increased permeability to both fluorescein sulfonic acid (FS) and fluorescein isothiocyanate-dextran (average molecular mass = 4000 Da; FD4). Lactic acid-induced hyperpermeability to both FS and FD4 was reduced by adding either 30 microM EUK-8, a superoxide dismutase/catalase mimetic, or catalase (10(4) U/mL). Incubation of monolayers with lactic acid increased cellular malondialdehyde content, a measure of lipid peroxidation. EUK-8 (30 microM) completely abrogated this effect. Incubation with ferrous sulfate (100 microM) exacerbated both lactic acid-induced hyperpermeability to FS and lactic acid-induced lipid peroxidation. Iron chelation with 1 mM diethylene triamine pentaacetic acid (DTPA)-trisodium calcium salt attenuated lactic acid-induced hyperpermeability, whereas iron-loaded DTPA (1 mM) was not protective. Treatment with DTPA-trisodium calcium salt also ameliorated lactic acid-induced lipid peroxidation. Incubation with lactic acid (pHo 5.0) for 16 h increased the cellular content of low molecular weight iron species. Incubation with lactic acid (pHo 5.0) for 24 h significantly increased the percentage of oxidized protein-bound thiols in Caco-2BBe cells. We conclude that lactic acidosis induces hyperpermeability in Caco-2BBe monolayers, in part, via an iron-dependent increase in reactive oxygen metabolite-mediated damage.     

Transbronchial lung biopsy for diagnosis of infiltrative pneumonic and round lesions

The cytological and histological studies of biopsy specimens obtained from 51 patients with infiltrative pneumonic formations in the lung (Group 1) and in 30 with its round formations (Group 2) at transbronchial intrapulmonary biopsy could verify the etiology of the disease in 86.2 and 20.0% in Groups 1 and 2, respectively. Different diseases may run under the mask of tuberculosis in 36.6% of these patients.     

On segmentation of lung parenchyma in quantitative computed tomography of the lung

Our purpose in this study was to investigate the influence of segmentation threshold and number of erosions on parameters used in quantitative computed tomography (CT) of the lung (erosions are shrink operations on the segmented area). Parameters assessed were mean lung density, area of the segmented lung, two percentiles, and the pixel index, which is the relative area of the histogram below -905 Hounsfield Units (HU). We analyzed images of ten emphysematous and ten nonemphysematous patients, that had been scanned at carina level in inspiration and expiration, using sections of 1, 2, 3, 5, and 10 mm in combination with a standard, a smooth, and an ultrasmooth reconstruction kernel. The lungs were segmented using pixel tracing at thresholds of -200, -400, and -600 HU with 0-4 erosions, followed by histogram analysis. The area of the segmented lungs decreased with 0.9%-3.2% per 100 HU decrease in threshold and with 2.2%-3.1% per erosion, dependent on patient group and respiratory status. Estimated mean lung density changed up to 30% by changing the threshold and the number of erosions. The pixel index and the 10th percentile depended only slightly on threshold and number of erosions, but the 90th percentile showed a strong dependence of up to 40%. It is concluded that the segmentation protocol can have a large impact on densitometric parameters and that standardization is mandatory for obtaining comparable results. Ideally a threshold equal to the average of the densities of lung and soft tissue should be used, but -400 HU will do in a limited but common density range (-910 to -790 HU). For densitometry two erosions are recommended, for volumetry zero erosions should be used.     

Early diagnosis of herpes simplex virus encephalitis by single photon emission computed tomography (SPECT) in patients with normal MRI

Since treatment of herpes simplex virus encephalitis (HSVE) is most effective when started early, a sensitive and specific method for early diagnosis would be of great benefit. MRI and CT are commonly used for this purpose. In this study, we presented two patients who had serologically confirmed HSVE and had normal CT and MRI, but were diagnosed as having HSVE by means of SPECT in the early stage. Case 1 was a 56-year-old man who suddenly developed alexia. On admission, physical and neurological examination were unremarkable except for alexia, agraphia, acalculia, and left-right disorientation. Brain CT, MRI, and cerebral angiography were all normal. However, SPECT showed hyperaccumulation of 99m Tc-HM-PAO in the right temporal-occipital area. On the 5th hospital day, he became comatose. CSF study revealed marked pleocytosis. Even then, MRI including Gd-enhanced study was normal while SPECT continued to show hyperaccumulation. Detection of herpes simplex virus DNA in CSF by polymerase chain reaction was negative. Anti-HSV antibody titer in CSF and serum confirmed intrathecal production of the antibody on the 14th hospital day. Abnormal accumulation of tracer in SPECT returned to normal on the 31st day when he was alert but still had a mild Gerstman syndrome. Case 2 was a 61-year-old man with disturbance of consciousness, mental dysfunction, and generalized convulsion. He was diagnosed as having HSVE by means of CSF pleocytosis, detection of HSV DNA in CSF by polymerase chain reaction, and presence of anti-HSV antibody in the CSF. CT and MRI again revealed no abnormality while SPECT clearly showed hyperaccumulation in the left temporal lobe in an early stage. Hyperaccumulation of lipophilic tracer on SPECT study, especially in the temporal lobes, has been reported in the early stage of HSVE by previous investigators. Unlike MRI or enhanced CT, the increased tracer accumulation in SPECT does not reflect disruption of the blood-brain-barrier or inflammatory edema, but reflects hyperperfusion or some other HSVE related abnormality which is currently unknown. From these observations, we suggest that local hyperperfusion occurs before local inflammation, and that SPECT is the most useful scanning method for early diagnosis of HSVE when this disease is clinically suspected.     

Pulmonary function, smoking habits, and high resolution computed tomography (HRCT) early abnormalities of lung and pleural fibrosis in shipyard workers exposed to asbestos

To evaluate the presence of asbestos-related pleural and parenchymal abnormalities and their correlation with pulmonary function and smoking habits, 119 asbestos-exposed asymptomatic workers (mean age, 46.2 years; mean duration of asbestos exposure, 8.6 years; mean latency time, 21.6 years) with normal standard P.A chest radiographs were submitted to HRCT, CO-diffusing capacity and pulmonary function tests. HRCT scans were normal only in 31 (26%) examined workers; 31 (26%) subjects showed both pleural and parenchymal involvement, and 50 (42%) and seven (6%) had exclusively pleural and parenchymal abnormalities, respectively. Based on CO-diffusing capacity and pulmonary function tests, no significant difference was demonstrated between workers with pleural lesions and subjects with normal pleura; however, lower values of FVC were observed in the nonsmoking workers with parenchymal abnormalities in comparison with nonsmoking subjects with normal parenchyma (78.2 vs. 89.7% of predicted values; p = 0.03 by student's two-tailed t test), and lower values of FEV1/FVC in the smokers with parenchymal lesions with respect to smokers with normal parenchyma (93.7 vs. 100.2% of predicted values; p = 0.005 by students' two-tailed t test). In conclusion, our results demonstrate that HRCT may detect early parenchymal abnormalities which correlate with exposure to asbestos and respiratory function impairment, including a reduction in obstructive indices in smokers occupationally exposed to asbestos, without any clinically evident disease.     

3D reconstruction by high resolution MR tomography of the inner ear

By means of modern 3D-visualization systems it is possible to render detailed reconstructions of very small morphological structures such as the inner ear. Aim of the present study was to demonstrate the imaging quality of a new 3D-segmentation program developed in the University of Hamburg. The investigation was carried out on a high-resolution MR-tomography of the author's labyrinth and facial nerve. The images were obtained with a fast-field-echo technique using a surface coil. 32 axial slices of 1.0 mm thickness were used for reconstruction. Thus it was possible to completely visualize cochlea, semicircular canals and facial nerve. Especially the filiform substructures of the inner ear could reliably be reconstructed. So the content of information of the MR-investigation could be increased by the 3D-technique applied.     

High resolution computed tomography (HRCT) of pulmonary infections in AIDS patients

The Escherichia coli RuvA and RuvB proteins mediate ATP-dependent branch migration of Holliday junctions during homologous genetic recombination. RuvA is a DNA-binding protein with high affinity for Holliday junctions, to which it directs RuvB (a DNA-dependent ATPase). Electron microscopic studies have shown that RuvB forms double hexameric rings on duplex DNA. To determine whether the rings are biologically active, the conditions required for their formation and activity have been analysed. The quaternary structure of RuvB appears to be dependent upon the binding of ATP, magnesium ions, and the presence of RuvA. In the presence of Mg2+ and ATP, RuvB forms hexamers; however, in the presence of Mg2+ alone, dodecamers were observed. Both forms of the protein are stable and have been isolated by gel filtration. Performed dodecamers and, to a lesser extent, hexamers assembled in the absence of DNA lack ATPase activity. Maximal ATPase activity was observed when RuvB assembled directly on DNA in the presence of Mg2+ and ATP. Moreover, under these conditions, a direct interaction between RuvB hexamers and tetramers of RuvA was observed.     

Potentialities of present day computed tomography in diagnosis of stomach cancer

Based on the findings of 206 examinations, the authors advance their opinion of the role of X-ray computed tomography (XRCT) in the diagnosis of gastric cancer. The authors think that if their developed procedure for X-ray computed tomography based on the use of usual air as the only contrast agent by measuring it out in doses and administering into the gastric at CT scanning, which is called pneumoroentgenocomputered tomography (PRCT), is employed, it, preserving all the traditional, already known, advances of XRCT additionally yields highly valuable information on a direct damage to the gastric wall itself. The findings suggest that PRCT is especially effective in intramurally growing gastric cancers, the so-called squamous carcinomas, which are hardly differentiated for diagnosis and which are most common. Noteworthy is the fact that in seemingly unquestionable exophytic gastric cancer, detecting intramural tumorous infiltration adjacent to the exophyte, PRCT thus provides evidence that the exophyte revealed is the peculiar top of an iceberg, whose base shows a significant exophytic gastric carcinoma.     

X-ray computed tomography in the diagnosis of peritoneal and retroperitoneal neoplasms

CT findings of peritoneal and retroperitoneal neoplasms were evaluated in 24 patients. The accuracy of CT in locating peritoneal and retroperitoneal tumors was 87% and in differentiating benign from malignant ones 96%. It is difficult to evaluate the tumors histopathologically. We suggest that CT scan be preferable in diagnosis of tumors in that area.