Computed tomography features and patterns of pulmonary infections.
MATERIAL & METHODS: Sixty patients were selected based on clinical findings suggestive of pulmonary infections from indoor and outpatient departments associated with government medical college, Amritsar. Patients suffering from various pulmonary infections were included in the study for various CT patterns in pulmonary infections. Patients with malignant lung masses were excluded from the study. Spiral CT examination was done with Philips Brilliance 19P multislice whole body scanner. Before starting the scan patient was instructed about the breath holding technique which consists of three maximal inspiration and expiration followed by breath holding at the end of deep inspiration. Standard spiral chest CT protocol was used. The results of study was systematically collected, assimilated and statistically analyzed to draw valid conclusions.
RESULTS: The tuberculosis was most commonly diagnosed disease with 30(50%) cases, followed by viral pneumonia in 12(20%) cases, bacterial pneumonia 10(16.7%) cases, allergic bronchopulmonary aspergillosis 4(6.7%) cases, aspergilloma 2(3.3%) cases & invasive pulmonary aspergillosis 2(3.3%) cases. The consolidation with air bronchogram was found 41(68.33%) cases, "tree in bud" 5(8.33%) cases, ground glass opacity 26(43.33%) cases, fibrosis 18(30%) cases. Fibrocystic changes were found in 2(3.33%) cases, emphysema in 8(13.3%) cases, honey combing 2(3.33%) cases, pleural effusion 14(2.33%) cases and cavitation 13(21.67%) cases. One (1.67%) case showed pneumothorax,2(2.33%)cases showed hydropneumothorax, 2(2.33%)cases showed "air crescent" sign. CT halo sign was seen in 2(2.33%) cases, mediastinal shift was seen in 4(6.67%) cases. Lymphadenopathy was seen in 34(56.67%) cases and nodule in 12(20%) cases.
Consolidation was most common in tuberculosis in 19(31.67%) cases followed by bacterial pneumonia 10(16.6%) cases, viral pneumonia 6(10%) cases, allergic bronchopulmonary aspergillosis 4(6.6%) cases with 1 case each of invasive pulmonary aspergillosis and aspergilloma.
Fibrosis was seen in 17(23.3%) cases followed by ground glass opacities 10(16.6%) cases of tuberculosis and 11(18.3%) cases in viral pneumonia. Lymphadenopathy was seen in 25(41.6%) cases in tuberculosis.
In tuberculosis, consolidation was more common in upper lobes (9 in right upper lobe, 8 in left upper lobe), in cases with bacterial pneumonia consolidation was more common in right upper lobe in 5 cases followed by right middle lobe in 3 cases, in cases with viral pneumonia consolidation was more common in right upper lobe in 3 cases followed by right middle lobe in 1 case, in cases with allergic bronchopulmonary aspergillosis consolidation was seen in right upper lobe in 2 cases and in cases with aspergilloma consolidation is seen in right middle lobe in 1 case, and in cases with invasive pulmonary aspergillosis consolidation was seen in right upper lobe in one case.
The consolidation was more common in right upper lobe in 20 cases followed by left upper lobe in 11cases. GGOs were uniformly distributed in both lung fields. Fibrosis and cavitation were more common in upper lobes .CT halo sign was seen in only one case. In tuberculosis patients tree-in-bud was distributed in right upper lobe in one case, left upper lobe in one case, right whole lung in one case and in left whole lung in one case. In patients with allergic bronchopulmonary aspergillosis, tree-in-bud was more common in left upper lobe in 2 cases. The ground glass opacities were more commonly distributed in 23 cases bilaterally. The fibrosis was more commonly seen in tuberculosis in right upper lobe in 7 cases followed by left upper lobe in 6 cases and right whole lung in 5 cases. The most common type of emphysema was paraseptal in 5 cases followed by compensatory emphysema in 2 cases with centrilobular emphysema in one case.
Bronchiectasis was common in upper lobes in 2 cases each in tuberculosis, viral pneumonias and allergic bronchopulmonary aspergillosis especially in right upper lobe. In tuberculosis, pleural effusion was seen on right side in 2 cases, on left side it was seen in 3 cases and bilateral in one case.
In present 60 study cases, lymphadenopathy was commonly seen 34 cases (56.6%) In TB, there are 20 cases (33.33%) with upper paratracheal lymphadenopathy, followed by 8(13.3%) lower paratracheal lymphadenopathy. Viral and bacterial pneumonia showed predilection for paratracheal lymphadenopathy.
The peripheral blood examination showed increased Total leukocytic count in 10 cases of bacterial pneumonia,9 cases with tuberculosis and 2 cases of allergic bronchopulmonary aspergillosis. TLC was decreased in 7 cases of viral pneumonia. Lymphocyte count was increased in 19 cases of tuberculosis with increased neutrophil in 5 cases. Nine cases of bacterial pneumonia showed increased neutrophil. Viral pneumonia showed increased lymphocytic count in 10 cases. Eosinophils were mainly increased in fungal infections.
DISCUSSION: The advent of computed tomography has made it easy to diagnose and treat pulmonary infections .The complicated and confusing chest infections require excellent two dimensional discriminatory capabilities of computed tomography for diagnosis.
Demirkazik FB et al studied CT findings of pulmonary infections in 57 immunocompromised patients. They concluded that 20(35.05%) patients had fungal infection, 8(14.3%) patients had viral infections, 19 (33.3%) patients had bacterial infection, 2 (3.5%) patients had tuberculosis and 8(14.3%) patients had Pneumocystis jiroveci pneumonia infection5. In current study cases, the most common pulmonary infection was tuberculosis 30(50%) cases, followed by viral pneumonia in 12(20%) cases, bacterial pneumonia in 10(16.67%) cases, the allergic bronchopulmonary aspergillosis in 4(6.6%) cases, aspergilloma in 2(3.3%) cases and invasive pulmonary aspergillosis in 2(3.3%) cases.
Reittner P et al, studied 114 patients with different types of pneumonia. It was seen that consolidation was detected in 30(85%) patients with bacterial pneumonia, 22(79%) patients with mycoplasma pneumonia, 15(75%) patients with fungal pneumonia, 2(9%) patients with Pneumocystis carnii pneumonia and cystic lesions were seen in 5(23%) patients, pleural effusion in 14(40%) patients with bacterial infections, 3(15%)patients with fungal and 2(7%) patients with mycoplasma pneumonia (6). In current study, consolidation was seen in 19(31.67%) cases with tuberculosis, followed by 10(16.6%)cases with bacterial pneumonia, 6(10%)cases with viral pneumonia , 4(6.67%) cases with allergic bronchopulmonary aspergillosis and 1(1.6%) case each of invasive pulmonary aspergillosis and aspergilloma. Pleural effusion was seen in 7(11.6%) cases with tuberculosis followed by 4(6.6%) cases with bacterial pneumonia,2(3.3%) cases with allergic bronchopulmonary aspergillosis and 1 (1.6%) case with viral pneumonia.
Eisenhuber E studied that "tree in bud" appearance on CT was not specific for single pulmonary diseases but found in large number of diseases particularly in infectious diseases .In patients with pulmonary infection tree-in-bud sign was most commonly seen in tuberculosis in 72% patients, it is less frequently seen in viral infections and fungal infections (7). In our present study, "tree in bud" sign was most common in tuberculosis in 2(3.3%) cases followed by 2(3.3%) cases of allergic bronchopulmonary aspergillosis and 1(1.67%) case of viral pneumonia.
Franquet T et al, studied CT findings in 32 immunocompromised patients with cytomegalovirus pneumonia. It was found that ground glass opacity was seen in 21(66%) patients, multiple nodules in 19(59%) patients, air space consolidation in 19(59%) patients and tree-in-bud in 4(12.5%) patients8. In our study cases, viral pneumonia was seen in 12(20%) cases. In viral pneumonias the most common CT pattern was ground glass opacity in 11(18.3%) cases and consolidation in 6 (10%) cases followed by septal thickening in 3(5%) cases and 2(3.3%) cases each with emphysema and bronchiectasis.
Muller NL et al studied high resolution CT findings in severe acute respiratory syndrome in 29 patients. It was found out that ground glass opacities and consolidation predominately the upper zones in 2 patients, the middle zones in 5 patients and lower zones in 5 patients (9). In our study, consolidation was seen in 3 cases in upper lobes followed by 1 case each in middle and lower zones respectively in viral pneumonia.
Okada F et al, studied CT findings in pseudomonas aeruginosa pulmonary infection and found that in 35 patients the most frequent CT abnormality was ground glass opacification 34(97.1%) patients, followed by bronchial wall thickening 31(88.6%) patients, consolidation 23(65.7%) patients. Intralobular reticular opacity in 3(8.6%) patients (10).In our study, the most common CT abnormality in bacterial pneumonia cases was consolidation in 10(6.6%) cases, followed by cavitation in 3(5%) cases and ground glass opacities in 2(3.3%) cases.
Leung AN conducted a study and concluded that parenchymal opacification often associated with cavitation situated in the upper lobes and superior segments of lower lobes are the most frequent radiological manifestation of post primary tuberculosis (11).In our study, cavitation was seen in 8(13.3%) cases with tuberculosis.
Miller WT et al studied comparison of CT findings between viral and bacterial infections. It was found that imaging features differ significantly between these two types of infections. Diffuse air space opacification with ground glass opacity or both were seen more frequently in bacterial infections in 6(27%) patients, than in 2(2%) patients of viral infections (12).In our study, consolidation was more frequent in bacterial pneumonia 10(16.6%) cases and in 6(10%) cases of viral pneumonias.
Bruno C et al studied comparison of CT features of aspergillosis and bacterial pneumonia in 124 severely neutropenic patients. It was found that nodules (85) were more common than consolidation (39) in patients suffering from aspergillosis pneumonia. Consolidation (23) was more common than nodules (33) in bacterial pneumonia. Cavitations are more common in bacterial pneumonia (31/56) than in aspergillosis (22/68). Air crescent sign was more common in bacterial pneumonia (24) than in aspergillosis (6). 19 nodules were surrounded by halo, out of these 17 nodules were due to aspergillosis. It was concluded that "CT halo sign" is more specific for aspergillosis than cavitation and air crescent sign (13). In our present study, air crescent was seen more commonly in aspergilloma 2 cases and CT halo sign was present in 2 cases of invasive pulmonary aspergillosis.
Greene R studied the radiological spectrum of pulmonary aspergillosis on CT. The various lesions identified were macronodules with halo sign, cystic bronchiectasis with mucus impaction in dilated bronchi giving "finger in glove" appearance, fungal ball in preformed cavities of lung giving "air crescent" or meniscus sign (14). In current study cases, in aspergillosis, air crescent sign was seen 2(3.3%) cases with aspergilloma, CT halo sign was seen in 2(3.3%) cases with invasive pulmonary aspergillosis and bronchiectasis was seen in 3(5%)cases with allergic bronchopulmonary aspergillosis and 2(3.3%) cases with aspergilloma.
Gosset N et al did study on tree-in-bud pattern and it was found that tree-in-bud is indication of endo and peribronchial disorder with dilatation, bronchial wall thickening, peribronchial inflammation and impaction of bronchia l lumen with mucus, pus and fluid and is found in variety of disorders including infections (bacterial, fungal, viral, parasitic) (15).
Joeng Y J et al did a study on pulmonary TB imaging and management and it was found that most common CT finding of reactivation of pulmonary TB are centrilobular nodules, tree-in-bud, lobar consolidation and cavitation. In primary TB, the most common finding was lymphadenopathy typically with central low attenuation which represented caseous necrosis and peripheral rim enhancement due to granulomatous inflammatory tissue (16).
Miller WT et al did a study on comparison of CT findings between viral and bacterial infections and it was found that imaging feature that was significantly different between the two types of infection was frequency of diffuse air space disease. Diffuse air space opacification with ground glass opacity or consolidation or both was seen with a much higher frequency in bacterial infections in 6(27%) patients than in viral infections in 2(2%) patients (17).
CONCLUSION: Multi detector CT is useful technique in diagnosing and determining the pattern and distribution of pulmonary infections. The vivid patterns of pulmonary infections and their distribution are better seen on CT than conventional radiography. The imaging features of pulmonary infections along with other investigations like peripheral blood examination and sputum examination can easily lead to final diagnosis.
The pattern and distribution of pulmonary infections on CT examination can aid in management of the patient .The most common pulmonary infection in India is tuberculosis and shows variable patterns on CT examination. The CT examination allows to reach the diagnosis earlier than conventional radiography and can thus considerably lower the mortality and morbidity associated with pulmonary infection
FIGURES & LEGENDS
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Sohan Singh , Arvinder Singh , GBS Mahal , Balwinder Kaur , Manjeet Kaur , Harpreet Garcha 
[1.] Professor & Head, Department of Radiodiagnosis, Government Medical College Amritsar
[2.] Associate Professor, Department of Radiodiagnosis, Government Medical College Amritsar
[3.] Associate Professor, Department of Radiodiagnosis, Government Medical College Amritsar
[4.] Senior Resident, Department of Chest & TB, Government Medical College, Patiala
[5.] Associate Professor, Department of Physiology, S.G.R.D, Amritsar
[6.] Junior Resident, Department of Radiodiagnosis, Government Medical College Amritsar
Dr. Arvinder Singh, 316-A Moon Avenue, Street No.1, Majitha Road, Amritsar 143001.
Table1: Disease wise ct distribution pattern in 60 study cases CT findings TB BP VP ABPA Consolidation 19(31.66%) 10(16.67%) 6(10%) 4(6.67%) Tree-in-bud 2(3.33%) -- 1(1.6%) 2(3.3%) GGO 10(16.67%) 2(3.3%) 11(18.3%) 1(1.6%) Fibrosis 17(28.3%) -- -- -- Fibrocystic changes 1(1.6%) -- 1(1.6%) -- Emphysema 6(10%) -- 2(3.3%) -- Honey combing 2(3.3%) -- -- -- Septal thickening 1(1.67%) -- 3(5%) -- Bronchiectasis 3(5%) -- 2(3.3%) 3(5%) Calcification 5(8.3%) -- -- -- Collapse 8(13.3%) 1(1.6%) -- -- Pleural thickening 3(5%) 1(1.6%) 1(1.6%) -- Pleural effusion 7(11.6%) 4(6.6%) 1(1.6%) 2(3.3%) Cavitation 8(13.3%) 3(5%) -- 2(3.3%) Pneumothorax 1(1.6%) -- -- -- Hydropneumothorax 1(1.6%) 1(1.6%) -- -- Air-crescent sign -- -- -- -- CT halo sign -- -- -- -- Mediastinal shift 4(6.6%) -- -- -- Lymphadenopathy 25(41.6%) 2(3.3%) 4(6.6%) 2(3.3%) Nodules 4(6.6%) 1(1.6%) 2(3.3%) 2(3.3%) CT findings IPA AG Consolidation 1(1.6%) 1(1.6%) Tree-in-bud -- -- GGO 2(3.3%) -- Fibrosis -- 1(1.6%) Fibrocystic changes -- -- Emphysema -- -- Honey combing -- -- Septal thickening -- -- Bronchiectasis -- 2(3.3%) Calcification -- -- Collapse -- -- Pleural thickening -- -- Pleural effusion -- -- Cavitation -- -- Pneumothorax -- -- Hydropneumothorax -- -- Air-crescent sign -- 2(3.3%) CT halo sign 2(3.3%) -- Mediastinal shift -- -- Lymphadenopathy 1(1.6%) -- Nodules 2(3.3%) 1(1.6%) Table Ii ct distribution of lymphadenopathy in 60 study cases Disease Upper Lower Sub Sub Para- Hilar paratrach paratrache carinal aortic aortic eal al TB 20 8 4 1 -- 5 VP 3 3 1 -- -- -- BP 2 1 -- -- -- -- ABPA 2 1 1 -- -- -- AG -- -- -- -- -- -- IPA -- -- 1 -- -- 1
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|Title Annotation:||ORIGINAL ARTICLE|
|Author:||Singh, Sohan; Singh, Arvinder; Mahal, G.B.S.; Kaur, Balwinder; Kaur, Manjeet; Garcha, Harpreet|
|Publication:||Journal of Evolution of Medical and Dental Sciences|
|Article Type:||Clinical report|
|Date:||May 27, 2013|
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