Chest X-Ray in pulmonary tuberculosis
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The Importance of Chest X-Ray
The chest radiograph is not considered as the gold standard and has limited role in the diagnosis of smear positive pulmonary tuberculosis . However its use is recommended for diagnosis of smear negative pulmonary tuberculosis for difficult cases.
- Repeat X-ray chest if done more than two weeks back or if x-ray chest is not available.
- Always ask for previous X- rays.
- Always examine the serial x-rays.
When serial chest radiographs shows progressive abnormality, particularly if the abnormality involves one or both upper lung zones and are not explained by any other disorder, suspect tuberculosis. Register patient as smear negative PTB case Start anti tuberculosis treatment, and refer back patient to PHC. These patients should be re-evaluated at the end of intensive phase at secondary level.
Typical findings suggestive of tuberculosis:
An untreated patient with typical finding on
X-Ray chest is less likely to be sputum negative
Involvement of upper zone with volume loss, as the result of fibrosis and destruction and presence of cavitations.
Hilar and mediastinal lymphadenopathy, non-cavitary infiltrates and lower zone involvement.
Radiological signs of complications:
- Endobronchial spread: Irregular, poorly defined, small nodular shadows and miliary mottling.
- Pleural effusion/ empyema: Homogenous opacity with obliteration of cardio and costo phrenic angles. Meniscus sign is seen.
- Pneumothorax: Hyper lucent area devoid of lung marking with collapsed borders
Persistent static shadows or improvement without anti tuberculosis treatment is less likely to be tuberculosis
Review the X-ray findings under the following headings:
•Normal structures on X-Ray chest
In majority of cases, pulmonary tuberculosis manifests itself by presenting radiological signs limited to the upper zones.
Chest X- ray can be divided into three radiological zones.
- Upper zone i.e up to lower margin of 2nd rib
- Mid zone i.e from lower margin of 2nd rib to lower margin of 4th rib
- Lower zone from 4th rib to diaphragm
radiological divisions on chest x-rays
Density is related to the structures ability to block photons. Air allows a greater number of photons to pass through and subsequently exposes more film generating a black image and bone block photons and therefore appears white.
Findings typically associated with pulmonary TB.
Opacification of airspaces within the lung parenchyma. Consolidation or infiltrate can be dense or patchy and might have irregular, ill-defined, or hazy borders
darkened area within the lung parenchyma, with or without irregular margins.Which may be surrounded by an area of airspace consolidation or infiltrates, or by nodular or fibrotic (reticular) densities, or both. The walls surrounding the dark area can be thick or thin. Calcification can exist around a cavity.
Nodule with poorly defined margins
Round density within the lung parenchyma, also called a tuberculoma. Nodules included in this category are those with margins that are indistinct or poorly defined. The surrounding haziness can be either subtle or readily apparent and suggests coexisting airspace consolidation.
Presence of a significant amount of fluid within the pleural space.arrow on left side indicates a cavity
Hilar &/or meditational lymphadenopathy
Enlargement of lymph nodes in one or both hila or within the mediastinum, with or without associated atelectasis or consolidation.
Miliary findings are nodules of millet size (1 to 2 millimeters) distributed throughout parenchyma.
Fibrotic scar with volume loss & retraction
Extensive bilateral fibro cavitory changes
Right Sided Pneumothorax
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