Septal thickening: HRCT findings and differential diagnosis

Thickening of the interlobular septa is a common and easily recognized high-resolution computed tomography feature of many diffuse lung diseases. In some cases, it is the predominant radiological finding. This article reviews the spectrum of entities that commonly present with thickening of the interlobular septa as the main radiological feature and establishes a practical approach for the differential diagnosis.

Radiological manifestations of pulmonary tuberculosis

Pulmonary tuberculosis (TB) is a common worldwide lung infection. The radiological features show considerable variation, but in most cases they are characteristic enough to suggest the diagnosis. Classically, tuberculosis is divided into primary, common in childhood, and postprimary, usually presenting in adults. The most characteristic radiological feature in primary tuberculosis is lymphadenopathy. On enhanced CT, hilar and mediastinal nodes with a central hypodense area suggest the diagnosis. Cavitation is the hallmark of postprimary tuberculosis and appears in around half of patients. Patchy, poorly defined consolidation in the apical and posterior segments of the upper lobes, and in the superior segment of the lower lobe is also commonly observed. Several complications are associated with tuberculous infection, such as hematogenous dissemination (miliary tuberculosis) or extension to the pleura, resulting in pleural effusion. Late complications of tuberculosis comprise a heterogeneous group of processes including tuberculoma, bronchial stenosis bronchiectasis, broncholithiasis, aspergilloma, bronchoesophageal fistula and fibrosing mediastinitis. Radiology provides essential information for the management and follow up of these patients and is extremely valuable for monitoring complications.

Photocatalytic treatment of diuron by solar photocatalysis: evaluation of main intermediates and toxicity

The technical feasibility, mechanisms, and performance of degradation of aqueous diuron (22 mg/L) have been studied at pilot scale in two well-defined photocatalytic systems of special interest because natural UV light can be used: heterogeneous photocatalysis with titanium dioxide and homogeneous photocatalysis by photo-Fenton. Equivalent pilot-scale (made up of Compound Parabolic Collectors (CPCs) specially designed for solar photocatalytic applications) and field conditions used for both allowed adequate comparison of the degree of mineralization and toxicity achieved as well as the transformation products generated en route to mineralization by both systems. Total disappearance of diuron is attained by both phototreatments in 45 min. 100% of chlorine was recovered as chloride, but total recovery of nitrogen as inorganic ions was not attained. 90% of mineralization was reached after 200 min of photocatalytic treatment, but toxicity measured by two different bioassays (Daphnia magna and a Microalga) was reduced to below the threshold (EC50%) in a shorter time. Transformation products evaluated by LC-IT-MS by direct injection of the samples were the same in both cases. The main differences between the two processes were in the amount of transformation products (DPs) generated, not in the DPs detected, which were always the same.

Accuracy of high-resolution CT in distinguishing between Pneumocystis carinii pneumonia and non- Pneumocystis carinii pneumonia in AIDS patients

The aim of this study was to assess the value of high-resolution CT in distinguishing between Pneumocystis carinii and non- Pneumocystis carinii pneumonia (PCP) in patients HIV-positive and high risk to have PCP. We performed a prospective study in 30 patients with <200 CD4 lymphocytes, clinical symptoms of pulmonary disease and chest X-ray non-conclusive for pulmonary infection. Evaluated CT findings included ground-glass opacities, reticulation, tree-in-bud appearance, consolidation, cystic lesions, bronchiectasis and lymphadenopathies. The diagnosis of "examination suggestive of PCP" was applied to cases showing a diffuse or predominant ground-glass pattern in the upper fields, associated or not with reticulations and small cystic lesions. The sensitivity, specificity, positive predictive value and negative predictive value of high-resolution computed tomography (HRCT) for the diagnosis of PCP was 100, 83.3, 90.5 and 100%, respectively. Pneumocystis carinii pneumonia was not demonstrated in any of the cases classified as "examination not suggestive of PCP". Significant small airway disease was not observed in any of the PCP cases. We conclude that HRCT is a reliable method for differentiating PCP from other infectious processes in HIV-positive patients and a good method to rule our PCP. Its inclusion in the diagnostic algorithm of lung infections is justified in these patients.

Fe(III)-solar light induced degradation of diethyl phthalate (DEP) in aqueous solutions

The degradation of diethyl phthalate (DEP) photoinduced by Fe(III) in aqueous solutions has been investigated under solar irradiation in the compound parabolic collector reactor at Plataforma Solar de Almeria. Hydroxyl radicals *OH, responsible of the degradation, are formed via an intramolecular photoredox process in the excited state of Fe(III) aquacomplexes. The primary step of the reaction is mainly due to the attack of *OH radicals on the aromatic ring. For prolonged irradiations DEP and its photoproducts are completely mineralized due to the regeneration of the absorbing species and the continuous formation of *OH radicals that confers a catalytic aspect to the process. Consequently, the degradation photoinduced by Fe(III) could be an efficient method of DEP removal from water.

Toxicity assays: a way for evaluating AOPs efficiency

The technical feasibility and performance of photocatalytic degradation of aqueous methomyl (50 mg/L) have been studied at pilot scale in two well-defined systems of special interest because natural-solar UV light can be used: heterogeneous photocatalysis with titanium dioxide and homogeneous photocatalysis by photo-Fenton. The pilot plant is made up of compound parabolic collectors specially designed for solar photocatalytic applications. Experimental conditions allowed pesticide disappearance, degree of mineralisation and toxicity achieved in the two photocatalytic systems to be compared. Total disappearance of methomyl is attained by photo-Fenton in 60 min and by TiO2 in 100 min. Hundred percent of nitrogen and sulphur are recovered as ammonium and sulphate. By contrast, complete mineralisation of total organic carbon (TOC) is not achieved even after quite a long time (more than 300 min). Three different bioassays (Vibrio fischeri, Daphnia magna and a Microalga) have been used for testing the progress of toxicity during treatment. All remained toxic down to very low-pesticide concentrations and in some bioassays were still toxic after total disappearance of the pesticide. Only if treatment is maintained throughout enough mineralisation (i.e. TOC disappearance), the toxicity is reduced to below the threshold (EC50%).

Miliary lung disease revisited

This article reviews the high-resolution computed tomography imaging features of miliary pattern, a characteristic radiologic manifestation of diffuse micronodular lung disease. The most common entities with this pattern are miliary tuberculosis, pneumoconiosis, sarcoidosis, metastases, and hypersensitivity pneumonia. According to the distribution of the nodules in relation to the secondary lobule, high-resolution computed tomography findings divide miliary patterns into 3 groups: centrilobular, perilymphatic, and random presentation. The radiologic features that help in the differential diagnosis are discussed.

New large solar photocatalytic plant: set-up and preliminary results

A European industrial consortium called SOLARDETOX has been created as the result of an EC-DGXII BRITE-EURAM-III-financed project on solar photocatalytic detoxification of water. The project objective was to develop a simple, efficient and commercially competitive water-treatment technology, based on compound parabolic collectors (CPCs) solar collectors and TiO2 photocatalysis, to make possible easy design and installation. The design, set-up and preliminary results of the main project deliverable, the first European industrial solar detoxification treatment plant, is presented. This plant has been designed for the batch treatment of 2 m3 of water with a 100 m2 collector-aperture area and aqueous aerated suspensions of polycrystalline TiO2 irradiated by sunlight. Fully automatic control reduces operation and maintenance manpower. Plant behaviour has been compared (using dichloroacetic acid and cyanide at 50 mg l(-1) initial concentration as model compounds) with the small CPC pilot plants installed at the Plataforma Solar de Almería several years ago. The first results with high-content cyanide (1 g l(-1)) waste water are presented and plant treatment capacity is calculated.

[Epidemiological status of Chagas disease in the endemic area from Region II of Antofagasta]

During 1997 a seroepidemiological study on Chagas' disease was carried out in 18 localities of three provinces (Tocopilla, El Loa and Antofagasta) of Region II (20 degrees 56'-26 degrees South Lat.; 70 degrees 38'-67 degrees West Long.), in order to assess the impact of the control program against Triatoma infestans launched in 1988, based on insecticide spraying of dwellings. By means of ELISA and an indirect hemagglutination test for Chagas' disease blood samples from 1,034 children under 10 years of age were examined, arising a 0.5% (3 cases) positivity. Test resulted positive in 2 (0.9%) children from the locality of San Pedro de Atacama and 1 (0.4%) from Calama city, all in the age group 6-10 year-old. However, none of their dwellings were found infested with T. infestants. These results indicate that the control program has a good possibility to prevent new human infections. It is advisable to continue the seroepidemiological and entomological vigilance and remark the necessity of increasing the effort in the study of transmission through other routes, to adopt or reinforce the pertinent preventive measures.

Interaction between Alzheimer's disease beta A4 precursor protein (APP) and the extracellular matrix: evidence for the participation of heparan sulfate proteoglycans

The interaction between the Alzheimer amyloid precursor protein (APP) and an intact extracellular matrix (ECM), matrigel, obtained from Engelbreth-Holm-Swarm tumors was evaluated. Based on quantitative analyses of the binding data obtained from solid phase binding assays, two binding sites on the ECM were identified for [125I]-APP (with apparent Kd1 of 1.0 x 10(-11) M and Kd2 of 1.6 x 10(-9) M respectively). Over 70% of [125I]-APP was displaced by heparin and N-desulfated heparin but not by chondroitin sulfate. Pretreatment of matrigel with heparitinase decreased the binding of [125I]-APP by 80%. beta-amyloid peptides (residues 1-40, 1-28, and 1-16) containing a heparin binding domain also displaced 80% of bound [125I]-APP, which was totally displaced by intact APP. The binding of [125I]-APP to matrigel increased by 210% with a decrease in the pH. These observations suggest that [125I]-APP interacts mainly with heparan sulfate proteoglycan present in the ECM. The binding of [125I]-APP to individual ECM components was also analyzed. [125I]-APP was found to bind laminin and collagen type IV but not fibronectin. However, when these ECM constituents were combined, the extent of APP-binding decreased significantly, to levels comparable to those obtained with intact matrigel, suggesting that multiple interactions may occur between ECM constituents and [125I]-APP. The results are discussed in terms of APP function and amyloidogenesis.

The dysmorphic lung: imaging findings

Congenital lung malformations are not infrequent and can be discovered in adults. It is, therefore, necessary to know their radiological manifestations in order to avoid diagnostic errors. We classify the congenital lung malformations in two main groups: dysmorphic lung and focal pulmonary malformations. We review the radiological spectrum of dysmorphic lung, based on a classification that emphasises the pulmonary abnormality, adding variants when diaphragmatic or venous abnormalities are present. In our opinion this approach allows for a rational use of advanced imaging techniques (CT, MRI).

[Current human and canine seroprevalence of Chagasic infection in San Pedro de Atacama County, II Region of Antofagasta, Chile, 1995]

In order to assess the impact of a control program against Triatoma infestans launched in 1988, based on insecticide spraying of dwellings, a serological survey for chagasic infection was carried out during 1995 in three localities from San Pedro de Atacama County (22 degrees 55' South lat., 68 degrees 12' West long.), II Region of Antofagasta in northern Chile. Blood samples from 531 children and adolescents and 65 dogs were subjected to ELISA test and indirect immunofluorescent test for Chagas' disease respectively. Tests resulted positive in 12 (2.3%) persons, all above 5 years old, in contrast with the 16.8% serological positivity observed in 1985. Three (4.6%) dogs (two 0-12 months old) resulted positive. These results indicate that dwelling sprayings with long-term activity insecticides against T. infestans is a good tool to prevent new human infections with T. cruzi. However, active vector transmission among domestic animals (canines) could be recently acquired.

Imaging of pulmonary-cutaneous disorders: matching the radiologic and dermatologic findings

Dermatologic lesions are often associated with pulmonary disorders and vice versa. Diseases with pulmonary and cutaneous manifestations can be divided into four major categories: (a) congenital and developmental disorders with cutaneous-pulmonary manifestations (Ehlers-Danlos syndrome, generalized elastolysis, yellow nail syndrome, neurofibromatosis, hereditary hemorrhagic telangiectasia); (b) primary dermal diseases with associated pulmonary manifestations (septic vasculitis, malignant melanoma, Kaposi sarcoma); (c) primary pulmonary diseases with associated cutaneous manifestations (tuberculosis, Pseudomonas pneumonia, mycoplasmal pneumonia, adenocarcinoma, metastasis); and (d) cutaneous-pulmonary conditions (multisystem disorders) (progressive systemic sclerosis, systemic lupus erythematosus, Wegener granulomatosis, sarcoidosis). A series of selected cases is used to illustrate the radiologic and dermatologic features of conditions that affect both the lung and dermal tissue. Specific emphasis is placed on the dermatologic manifestations of disease. Diagnosis of a pulmonary-cutaneous disorder requires familiarity with the morphologic appearance of the cutaneous lesion.

CT recognition of traumatic herniation of the stomach: the "sandwich" sign

We describe a new sign of traumatic herniation of the stomach. Computed tomography (CT) shows the herniated stomach as two semicircular loops separated by a band of soft-tissue attenuation somewhat resembling a sandwich. This appearance is the axial representation of the herniated stomach.

Increased density of the azygos lobe on frontal chest radiographs simulating disease: CT findings in seven patients

OBJECTIVE

Our objectives were to show that an opaque azygos lobe on the anteroposterior chest radiograph can be a normal finding and to investigate the causes of the increased density.

MATERIALS AND METHODS

We prospectively examined 53 patients seen during a 3-year period in whom an azygos lobe was detected on chest radiographs. The size of the lobe was determined by the location of the trigone on chest radiographs. The trigone is the triangular area that marks the upper portion of the azygos fissure. If the trigone was located on the lateral aspect of the pulmonary apex, the azygos lobe was classified as type A (nine patients); if the trigone was situated at the midpoint of the cupula of the apex, the lobe was considered type B (20 patients); if the trigone was located on the medial face of the apex, the lobe was considered type C (24 patients). An opaque azygos lobe was defined as an increase of density suggestive of a pulmonary or mediastinal process. The findings on chest radiographs were compared with those on CT scans, which were obtained in all patients.

RESULTS

Radiographs showed abnormally opaque azygos lobes in seven patients. Three cases were type B and the opaque lobe had a triangular aspect, suggesting pulmonary disease. Four cases were type C and the opacity had a convex aspect, suggesting a mediastinal mass. In all cases, CT scans showed a shallow azygos lobe and increased depth of the soft tissues of the mediastinum in front of the azygos lobe. This appearance was caused by tortuosity of the supraortic vessels in six cases and by a shadow from a normal thymus in one case. No pathologic process was discovered in any of the patients.

CONCLUSION

We believe an opaque azygos lobe can be a normal finding, usually resulting from overlapping tortuous supraortic vessels.

[Anomalous origin of left coronary artery in pulmonary artery]

We report 2 infants aged 6 months and one year with an anomalous left coronary artery origin treated surgically at our centre with direct aortic reimplantation of the anomalous coronary. Evolution has been satisfactory, with a great improvement of ventricular function. The mitral incompetence and congestive heart failure have disappeared and myocardic perfusion electrocardiographic patterns were corrected. Because of the unfavorable natural course of the disease and the improvement in techniques of coronary revascularization in infants we recommend an early surgical treatment as soon as it be diagnosed. We consider that the most adequate surgical treatment is the direct aortic reimplantation of the anomalous coronary artery.

Endobronchial lipoma: CT diagnosis

Computed tomography was performed in two patients with endobronchial lipomas. Bronchoscopy was inconclusive, but CT provided the definitive diagnosis by demonstrating fat within the endobronchial tumor.

Imaging of the azygos lobe: normal anatomy and variations

We describe the normal appearance of the azygos lobe on plain radiography and CT. Several findings are presented that, to our knowledge, have not been previously reported, such as the inferior prolongation of the fissure, the apparent intrapulmonary path of the right brachiocephalic vein and superior vena cava seen on the anteroposterior chest radiograph, and the visible fissure on the lateral chest radiograph.

CT of congenital malformations of the lung

We reviewed 40 cases of congenital malformations of the lung that were studied with both plain radiography and computed tomography (CT). We compared the CT findings with those of radiography. We found that CT was helpful in the management of these cases because it helped confirm the diagnosis, demonstrated unsuspected findings, and better depicted anatomic extent of anomalies, thus allowing better planning for surgery. We believe that CT is the method of choice for the study of congenital lung malformations and that it should be used before more invasive procedures such as bronchography or aortography.

CT demonstration of intrapulmonary right brachiocephalic vein associated with an azygos lobe

We describe a rare anomaly demonstrated by CT in which the right brachiocephalic vein follows an extramediastinal course in the anterior portion of the azygos fissure.

Pulmonary nodule simulated on the lateral chest radiograph by branches of the aortic arch

A prospective study of 500 lateral radiographs of the chest showed a nodular opacity superimposed on the trachea above the aortic arch in 15 patients (3%). Because no abnormalities were identified on the posteroanterior radiograph or on CT scans, we assume that this pseudonodule is produced by branches of the aorta. In all cases, CT showed that the left subclavian artery or the innominate artery-right subclavian complex protruded into the lung.

Efficacy of cryosurgery alone for refractory monomorphic sustained ventricular tachycardia due to inferior wall infarction

The efficacy of cryosurgery alone was evaluated in 15 patients with refractory monomorphic sustained ventricular tachycardias related to inferior wall infarction. Patients were 64 +/- 9 (SD) years old and had a mean left ventricular ejection fraction of 39.2 +/- 11.2%. Thirty different tachycardias were mapped with the origin localized to the septum or inferior wall in 20 (67%), near the mitral valve anulus in 6 (20%) and at the base of the posterior papillary muscle in 4 (13%) tachycardias. Endocardial cryoablation of these sites was performed with 6 to 13 (mean 9.2 +/- 1.8) cryolesions per heart. No mitral valve replacement was performed. There was one postoperative death as a result of sepsis. Cryoablation abolished inducible ventricular tachycardia in 11 patients. Of the other three patients, the tachycardia in two was controlled with a single antiarrhythmic agent that had previously failed to suppress inducible ventricular tachycardia. Thus, clinical success was obtained in 13 (93%) of 14 patients. The remaining patient received an automatic implantable cardioverter defibrillator. Ejection fraction remained unchanged or improved after surgery in 14 patients (93%). There have been no late deaths, recurrence of sustained ventricular tachycardia or significant mitral regurgitation during a mean follow-up period of 19 +/- 7 months. These results compare quite favorably with those previously reported for subendocardial resection alone, and indicate that cryosurgery is highly effective, does not result in deterioration of left ventricular function and preserves mitral valve competence when cryoablation of the posterior papillary muscle is necessary.

Computed tomography as the method of choice in the diagnosis of emphysematous cholecystitis

Computed tomographic (CT) findings in 4 cases of acute emphysematous cholecystitis are described. The use of CT in the diagnosis of this condition is discussed in relation to the use of sonography and plain radiography.

Postoperative acute cholecystitis: sonographic diagnosis

This paper discusses ten patients who developed acute cholecystitis during the postoperative period following surgery which did not involve the gall bladder. All were examined with ultrasound during the first two weeks after surgery and were diagnosed as acute cholecystitis. Six (60%) had complications such as empyema, gangrene, perforation, pericholecystic abscess or localized peritonitis; four (40%) had no evidence of complications. The authors highlight the importance of ultrasound (US) as the technique of choice for a first screening if this entity is suspected because of its speed and high diagnostic reliability.

Fine-needle biopsy of the pancreas using real-time ultrasonography

Percutaneous fine-needle biopsy of the pancreas by real-time ultrasonography was performed in 45 patients with suspected pancreatic carcinoma. True-positive diagnoses were obtained in 27 cases, 11 examinations yielded true-negative results, 3 results were false-negative, 2 were equivocal, and 2 samples were inadequate. The overall success rate was 84.4%. No false-positive cytologic diagnoses were made. Complications were not seen in any of the patients. The results confirm the effectiveness, safety, and relatively low cost of this procedure.

Carcinoma of the hepatic flexure with proximal lymphatic invasion mimicking Crohn's disease

A case of carcinoma of the hepatic flexure with ileocolic lymphangitic spread that simulates Crohn's disease is reported. Careful evaluation of the primary lesion should give the key to the diagnosis.