[The role of imaging in thoracic tuberculosis]

Tuberculosis is an infectious disease mostly due to Mycobacterium tuberculosis. It is frequent in developing countries and its incidence is rising in developed countries. Lungs are the most involved organs of the chest but other structures can be affected. Imaging is fundamental in the management of the disease. Confirmation of diagnosis can be made only by bacteriologic and/or histologic exams. The first approach of diagnosis is based on clinical symptoms and chest X-ray signs. Radiologic signs depend on patient's age, his immune status and his previous contact with M. tuberculosis. Conventional chest X-ray remains the first-line exam to realize. It can suggest the diagnosis on the appearance and location of the lesions. CT scan is recommended for the positive diagnosis in case of discrepancy between clinical and radiographic signs, as for the diagnosis of parenchymal, vascular, lymph nodes, pleural, parietal or mediastinal complications. It is also essential for the evaluation of parenchyma sequelae. MRI and PET-scan have limited indications. The purpose of this article is to illustrate different radiological forms of chest tuberculosis, its sequelae and complications and to highlight the role of each imaging technique in the patient's management.

[Imaging of pulmonary artery involvement in Takayasu disease]

OBJECTIVES

Illustrate imaging aspects of pulmonary artery involvement in Takayasu's arteritis.

PATIENTS AND METHODS

Retrospective study of six patients among 28 patients with Takayasu arteritis whose disease involved the pulmonary arteries and to review their clinical and computed tomography data.

RESULTS

Mean patient age among those with pulmonary artery involvement was 34 years. All patients exhibited extensive lesions of systemic arteries. The most common computed tomography angiography sign was wall thickening. Dilatation of the pulmonary artery trunk was observed in one-third of cases.

CONCLUSION

Pulmonary arterial involvement in Takayasu's disease is not uncommon. Computed tomography is a reliable imaging technique to establish the diagnosis.

[Small-cell lung carcinoma: CT imaging features]

Small cell lung carcinoma (SCLC) typically is central in location. It is a very aggressive tumor characterized by its propensity for invasion of mediastinal structures, frequently, the ipsilateral pulmonary artery, multifocal nodal metastases and high frequency of distant metastases at initial presentation. CT is very sensitive and effective for local and regional staging. Combined with other diagnostic modalities, especially PET imaging, it allows whole body imaging for accurate staging, which is mandatory for therapeutic management. The different CT imaging features of SCLC and its more specific imaging characteristics will be reviewed in this article.

[Pseudotumoral mediastinal amyloidosis]

PURPOSE

Amyloidosis involvement of mediastinal nodes is rare. Isolated pseudotumoral involvement without extra-thoracic disease is a diagnostic challenge and typically raises concern for underlying malignancy. We present 3 cases of pseudotumoral mediastinal amyloidosis.

METHODS

We report the cases of 3 patients presenting with recent onset of respiratory symptoms. Bronchoscopy showed mucosal infiltration suspicious for lymphangitic spread of tumor. The patients underwent chest radiography complemented by CT of the chest and abdomen, and laboratory and immunological work-up. A diagnosis of pseudotumoral mediastinal amyloidosis was confirmed by mediastinoscopic biopsy in all cases.

RESULTS

CT showed a pulmonary and mediastinal tumor process in 2 cases and pericarinal tumor in 1 case. Diffuse bronchial wall thickening was present in all cases. Review of biopsy material showed tracheobronchial amyloidosis in 1 case. Patient work-up showed no evidence of extra-thoracic amyloidosis. Rapid progression of bronchial obstruction was observed in 1 case.

CONCLUSION

The imaging features of mediastinal amyloidosis are non-specific. Pseudotumoral involvement of mediastinal nodes associated with pulmonary amyloidosis accelerates the degree of airway obstruction.

[Pulmonary hyalinizing granuloma: review of two cases]

Pulmonary hyalinizing granuloma is a rare fibrosing nodular disease of the lung characterized by solitary or multiples pulmonary nodules. This report describes two cases of this rare disorder. MRI was available in one case. For the first case, the stability of the lesions and past history of retroperitoneal fibrosis suggested the diagnosis. For the second case, open lung biopsy was required for diagnosis. When multiple nodules are present, metastatic disease cannot be excluded and biopsy may be required. Evolution is usually benign but follow up is necessary.

[Value of CT scanning in the investigation of thoracic sarcoidosis]

INTRODUCTION

Sarcoidosis is a systemic disease of unknown aetiology that includes a pulmonary or mediastinal component in 90% of cases. The aim of this study is to clarify the contribution of thoracic CT scanning in the diagnosis and differential diagnosis of sarcoidosis and its role in the follow-up and the evaluation of the activity of the disease.

METHODS

It is a retrospective study of 39 patients with histologically confirmed sarcoidosis. All patients had one or more thoracic CT scans.

RESULTS

The most common parenchymatous lesions were lymphatic micronodules and peri-bronchovascular thickening. The right paratracheal chain and the hilar nodes were the most frequently involved.

CONCLUSIONS

The CT scan is better than the chest x-ray at studying the parenchymal lesions and lymph node involvement in sarcoidosis. It helps in the differential diagnosis of sarcoidosis and other granulomatous disorders, especially tuberculosis. It also allows follow up of patients for the detection of complications, particularly fibrosis. Its role in the assessment of disease activity remains controversial.

[Ultrasonographic, CT, and MRI findings of chest wall hydatidosis]

The chest wall is an uncommon localization for hydatid disease even in countries where echinococcosis is endemic. Only isolated sporadic cases have been reported in the literature. We reviewed retrospectively 15 patients who underwent surgery for chest wall hydatid disease. Various imaging techniques were used for diagnosis of our cases. These included chest radiograph, thoracic ultrasonography, computed tomography and magnetic resonance imaging. Hydatid cyst involved soft tissues (n=5), ribs and vertebrae (n=5), ribs (n=4) and sternum (n=1). Imaging techniques were of value for diagnosis (radiographs and sonography) and for evaluation of the extent of involvement (CT and MRI). Chest wall hydatidosis requires surgical treatment but recurrence is frequent.

Tracheobronchopathia osteochondroplastica presenting as a respiratory insufficiency: diagnosis by bronchoscopy and MRI

Tracheobronchopathia osteochondroplastica (TO) is a rare benign disorder affecting the trachea and occasionally the bronchi. We report a case of TO presenting as a respiratory insufficiency. Chest radiograph revealed an irregular narrowing of the intra thoracic trachea and a parenchymal consolidation of the left lower lobe. Magnetic resonance examination of the chest showed a diffuse irregular thickening of the trachea and central bronchi, which had an intermediate signal intensity with punctiform low signal intensity suggesting calcifications and no contrast enhancement. The diagnosis was confirmed by bronchoscopy and biopsies.

[Tuberculosis of the lung bases]

Tuberculosis of the lung bases is a rare condition that can mimic pneumonia, bronchial carcinoma, lung abscess or bronchiectasis. Diagnostic delays, that can lead to serious complications not amenable to surgical resection, are often the result of repeatedly negative bacteriological examinations. We report a series of 10 cases of tuberculosis of the lung bases collected between 1993 and 1998 that were examined by computerised tomography. The chest x-ray most commonly showed a heterogeneous opacity. On the CT scan this corresponded with an area of alveolar consolidation which, when it was associated with centrilobular micronodules and cavitated nodules and masses, suggested the diagnosis of basal tuberculosis. Indeed the absence of apical lesions and the frequency of involvement of mediastinal and bronchial lymph nodes support the hypothesis of bronchial dissemination of the bacilli from tuberculous nodes. This explanation is supported by the high incidence of endobronchial lesions found at bronchoscopy in this form of tuberculosis.

[Radiological and clinical aspects of bronchogenic lung cysts: 4 case reports]

Bronchogenic lung cysts are exceptional. We report four cases which raised a problem of differential diagnosis. Our patients included four women and a young boy (age range 12 - 36 years). The first patient consulted for bloody purulent sputum in a context of an infectious syndrome. The second patient had lower right-sided chest pain. The cyst was a fortuitous discovery in the other two cases. In one case, the chest x-ray disclosed a thin-walled cavity of the upper right lobe, confirmed on the CT scan which also evidenced intracavitary partitions. In two other cases, the chest x-ray showed a liquid-filled opacity (one in the lower right lobe and the other in the upper right lobe) and no further specificity on the CT scan. In the last case, a liquid-air cavity was evidenced. Upper right lobectomy was performed for the case with an air-filled cavity and tumorectomy for the other cases. Pathology reported bronchogenic cyst in all cases. The radiological and clinical presentations observed in patients with bronchogenic lung cysts, with or without tracheobronchial communication, are polymorphous, often raising problems of differential diagnosis.