Role of Computed Tomography in Diagnosis of Diffuse Lung Diseases Chauhan Jayant 1*, Panchal Pankaj 2, Faruqui Tehzeeb 3

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1 ORIGINAL ARTICLE Role of Computed Tomography in Diagnosis of Diffuse Lung Diseases Chauhan Jayant 1*, Panchal Pankaj 2, Faruqui Tehzeeb 3 1 MD,DTCD,Additional Professor& HOD, 2,3 MBBS, 3 rd year resident in Dept.of TB & Respiratory Medicine, Medical college Baroda, SSG Hospital,Vadodara. ABSTRACT BACKGROUND AND OBJECTIVES: Diffuse lung diseases are those in which the disease process is widespread involving both the lungs but need not affect all lung regions uniformly. Plain chest radiograph though inexpensive, excellent modality of choice, the pattern of diffuse lung disease on radiography is often nonspecific. Computed Tomography can detect normal and abnormal lung interstitium and morphological characteristics of both localized and diffuse lung diseases. The aims and objectives was to study the normal anatomy of the lung with respect to secondary pulmonary lobule; to evaluate the importance of computed tomography in the diagnosis of diffuse lung diseases; to detect diffuse lung diseases in patients who had abnormal radiographic abnormalities with symptoms suggestive of diffuse lung disease; to determine the site of CT guided lung biopsy for confirmation of diagnosis in suspicious diseases and to study the various patterns of diffuse lung diseases on HRCT& CECT. METHODS: A total number of 50 patients with suspected or known interstitial lung disease were studied by highresolution computed tomography (HRCT) & Contrast enhanced computed tomography (CECT) over a period of 8 months. RESULTS: In the current study the most common cases are of Carcinoma of Lung (20 cases (40%)). Next common condition observed was Tuberculosis in 10 (20%) cases &Bronchiectasis in 9 (18%) cases out of 50 cases and followed by Idiopathic pulmonary fibrosis, pneumonia and emphysema. CONCLUSION: Computed Tomography is confirmatory in diagnosis of lung carcinoma, tuberculosis, Bronchiectasis &idiopathic pulmonary fibrosis. Keywords: lung diseases, HRCT, CECT INTRODUCTION Diffuse lung diseases are those in which the disease process is widespread involving both the lungs but need not affect all lung regions uniformly. A large number of diseases cause diffuse infiltration of lung parenchyma and are therefore better described as infiltrative lung diseases. Pulmonary interstitium is the network of connective tissue fibers that supports the lung which includes interlobular septa, alveolar walls and the peri bronchovascular interstitium. Interstitial lung diseases are characterized by alveolar septal thickening, fibroblast proliferation, collagen deposition and if the process remains unchecked, it will lead to pulmonary fibrosis. *Corresponding Author: Dr.Jayant B Chauhan 77, Vandematram Township, Opp.Vishwas City-3, Gota, Ahmedabad Contact No: jbchauhan15@yahoo.com Lung carcinoma are characterised by abrupt cut off of bronchus and with or without metastasis. Pleural mass seen as pleural based nodule may invade bronchus or not. The limitations of plain chest film in the assessment of lung disease especially diffuse lung disease and difficulties of characterizing lung morphology precisely became even more evident when computed tomography was introduced as a new tool in radiographic imaging. High resolution computed tomography (HRCT) was introduced in 1985 by Zerhouni et al, the perfect imaging modality for characterization and diagnosis of diffuse lung diseases. HRCT is a radiological imaging technique best suited for revealing changes in lung structure. Various HRCT findings taken together can represent typical patterns. HRCT provides global anatomic assessment of the lung improving significantly specificity and sensitivity of the clinical diagnosis. HRCT in combination with laboratory tests, 5 Int J Res Med. 2017; 6(3); 5-11 e ISSN: p ISSN:

2 physiological studies and invasive procedures proved to be a useful tool in reaching the differential diagnosis or final diagnosis. Contrast enhanced computed tomography (CECT) is supposed to give better images of certain areas of lungs as compared to coventional CT chest. In CECT chets a radioactive substance is given to the patient either orally or through injection before the test. In accordance with diffuse lung diseases Computed Tomography plays major role in finding out as following; presence of disease in lung; type of disease; changes of active lung disease; site and type of biopsy to be performed; change in disease activity following treatment. MATERIALS AND METHODS A total number of 50 patients with suspected or known Respiratory disease were studied by high-resolution computed tomography (HRCT) or Contrast enhanced computed tomography (CECT) over a period of 8 months. The study group consisted of 50 patients, of this 41 were males (82%) and 9 were females (18%). The age group of patients varied from 21 years to 85 years. Selection criteria: Patients were selected on the basis of the following, 1. Clinical history suggestive of interstitial lung disease. 2. Known cases of interstitial lung disease. 3. Abnormal chest radiographs (with an abnormal opacity) OBSERVATIONS Total 50 cases of diffuse lung disease were studied by high resolution computed tomography & contrast enhanced computed tomography scanning of lungs in the department of TB & Respiratory Diseases, Baroda medical college & S.S.G.hospital, Vadodara, Gujrat, India. Age & Sex: The age group in which maximum number of patients (14) presented was 41-50, which included 11 (78.6%) males and 3 (21.4%) females. Then 12 patients in years and 11 patients in years of age group. Diffuse lung diseases are more common in males than in females. Out of 50 cases 41(82%) were males and 9 (18%) are females (Table 1 and 2). Table 1: Age & Sex distribution of studied patients Age Group (year) Total No. of patients 6 Int J Res Med. 2017; 6(3); 5-11 e ISSN: p ISSN: Male Female < Males are more in numbers in this study & years age group people more in number in this study. Table 2: Diagnosis & sex wise distribution of cases Diagnosis Total Male Female Idiopathic Pulmonary Fibrosis No. % No. % Bronchiectasis Emphysema Lung carcinoma Tuberculosis Miliary TB Pneumonia Figure 1: Case distribution according to age groups. Figure 2: Case distribution according to age & sex.

3 Etiological diagnosis: In the current study the most common cases are of Lung carcinoma. 20 (40%) out of 50 were observed during the course of this study. Next common condition observed was Tuberculosis, 10(20%) cases out of 50 cases, 2 of these cases are of Miliary Tuberculosis. and followed by bronchiectasis, Idiopathic pulmonary fibrosis & pneumonia (Table 3). Lung carcinoma most commonly observed in age group of years & Tuberculosis is most commonly affecting age group of years. (Table 4) Table 3: case distribution according to etiological diagnosis. Diagnosis No. of cases Percentase (%) Idiopathic Pulmonary Fibrosis 4 8 Bronchiectasis 9 18 Emphysema 2 4 Lung carcinoma Tuberculosis 8 16 Miliary TB 2 4 Pneumonia Table 4: case distribution according to age. Disease To tal < Idiopathic 4 2 _ 1 1 _' _ Pulmonary Fibrosis Bronchiectasis 9 _ Emphysema 2 1 _ 1 _ Lung 20 _ carcinoma Tuberculosis 8 _ 2 _ 2 _ 3 Miliary TB 2 _ 1 1 _ Pneumonia 4 _ Figure 4: Case distribution according to Etiological Diagnosis. Figure 5: Age distribution according to diagnosis. Clinical presentation: Out of 50 cases, 41 (82%) patients were primarily presented with cough, 35 (70%) patients presented with Breathlessness. Most of them were of Ca lung, Bronchiectasis and tuberculosis involving lungs. Some patients were having varied symptoms like fever, chest pain, hemoptysis, anorexia and weight loss. Figure 6: clinical features observed in 50 cases of diffuse lung diseases. Morphology & Location Hypersensitivi ty 1 1 _ Figure 3: Sex distribution according to Diagnosis. Abrupt cutoff of bronchus (38%) was most commonly observed morphological finding followed by pleural effusion (28%), bronchiectasis (24%), consolidation (24%) and lymphadenopathy (24%) (figure 8). The most common radiographic finding in 7 Int J Res Med. 2017; 6(3); 5-11 e ISSN: p ISSN:

4 lung carcinoma is abrupt cutoff of bronchus with lymphadenopathy with or without pleural effusion & metastasis. In the Tuberculosis patients there are tree in bud appearance and centrilobular nodules typically present and consolidation sometimes present. In Miliary Tuberculosis there are miliary nodules present. Bronchiectasis shows patchy ground glass opacities, interlobular septal thicking, dilated bronchi and signet ring sign. IPF shaws characteristic bilateral,basal,subpleural honeycombing and reticular pattern. Interlobar & interlobular septal thickening present in IPF. In pneumonia, a consolidation is seen mostly lower lobe involvement seen. Centrilobular emphysema characterised by multiple, small centrilobular lucencies with ill-defined wall scattered throghout the lung was observed in Emphysema. pneumonitis characterised by groundglass opacity &reticular pattern (Table 6). Diffuse lung diseases are predominantly bilateral but the lung carcinoma is predominantly unilateral. Table 5: Case distribution according to Lung Involvement Unilateral Lung Bilateral Lung No. of cases Involvement Involvement Figure 7: Case distribution according to lung involvement. Table 6: CT morphology in diffuse lung diseases observed in 50 cases. HRCT Findings IPF Bronchiectasis Emphysema Ca Lung Tuberculosis miliary TB Pneumonia Reticular 4 1 _ 1 Nodular 2 _ Ground glass 1 1 _ 2 2 _ 2 1 Bronchiectasis 2 10 Honeycombining 4 _ Consolidation _ 3 5 _ 4 _ Emphysema _ Fibrotic Bands 1 5 _ 2 1 _ Miliary nodules _ 2 Abrupt cutoff of bronchus _ 19 Metastasis _ 10 Lymphadenopathy 1 _ _ 1 _ Pleural effusion _ 10 3 _ 1 _ Pleural thickening _ 8 Int J Res Med. 2017; 6(3); 5-11 e ISSN: p ISSN:

5 Figure 8: CT morphology in diffuse lung diseases observed in 50 cases. DISCUSSION A total number of 50 patients with suspected or known Respiratory disease were studied by high-resolution computed tomography (HRCT) or Contrast enhanced computed tomography (CECT) over a period of 8 months. Lung Carcinoma: Study included twenty (40%) cases of lung carcinoma out of which 19 cases have abrupt cutoff of bronchus, 10 cases shows metastasis & pleural effusion, 5 cases shows lymphadenopathy, 3 cases with consolidation &emphysema. Fiftin of the twenty cases has unilateral involvement. Six patients were seriously ill & 5 patients presented with Hemoptysis. Left Lung Mass with Abrupt Cutoff of Left Upper Lobe Bronchus. Tuberculosis: Study included 10 (20%) cases of tuberculosis out of which 4 were old patients with symptoms suggestive of reactivation of the disease. Cavities were seen in all 4 patients. Other findings such as pleural thickening were seen in 1 patients and mediastinal lymphadenopathy in 5 patients were described as explained by Im JG et al. 8 Two of the 6 new cases, diagnosed as military TB on HRCT showed randomly distributed nodules (2-3) mm commonly involving the perivascular and subpleural regions-consistent with findings of Hong SH et al and Voloudaki AE et al the remaining three cases showed tree in bud appearance consolidation, cavitation as described by Im JG et al. 8,17,18 Centrilobular Nodules Present S/O Tuberculosis Miliary Nodules Seen In Miliary Tuberculosis Bronchiectasis: It was detected in nine patients commonly affecting left middle lobe in 5 patients and right lower lobe in four patients.lobar as well as segmental dilatation was possible in all patients as stated by by Cooke JS et al. 9 The characteristic signet ring sign described by Grenier P et al was identified in 7 patients. 10 Fibrotic bands seen in 5 patients. Dilated bronchi & Signet ring sign seen in both the lungs s/o Bronchiectasis. 9 Int J Res Med. 2017; 6(3); 5-11 e ISSN: p ISSN:

6 Bilateral basal honeycombing present with architectural distortion s/o UIP in this case IPF Idiopathic pulmonary fibrosis: In the present study we had seen 4 cases of IPF. On HRCT posterior basal and sub pleural areas were commonly affected in all patients (100%). Middle lobes and anterior segments of upper lobe involvement were seen in 4 patients suggesting disease process begins in posterior basal regions progressively involving the upper regions. These findings were correlated with findings of Lim MK et al and Battista G et al. 5,6 Finding of honeycombing found as thick walled small air containing cystic spaces sharing walls and lying in the layers in posterior basal regions correspond to the findings of Nishiyama O et al. 7 Intralobular interstitial thickening, irregular thickening of interlobular septa, pleural thickening and traction bronchiectasis are some other findings noted in cases of IPF. Emphysema: Our Study included two patients of emphysema showed centrilobular emphysema characterised by bilateral multiple small centrilobular lucencies with ill-defined walls scattered throughout the lungs in according to findings of Stern EJ and Frank MS, Webb WR et al and Murata K et al. 12,13,14 Pneumonia: We studied four cases of pneumonia of which two cases shows Ground glass opacities, all four cases have lower lobe involvement & three of these shows emphysematous changes also. In one patient there is a minimal pleural effusion is noted. One patient of four is seropositive. : One patient in our study was of. Which has characteristic ground glass appearance in both the lungs in mid & lower lobe and reticular densities in bilateral lower lobe seen? This Patient was seropositive. CONCLUSION Computed Tomography is confirmatory in diagnosis of lung carcinoma, tuberculosis, bronchiectasis & idiopathic pulmonary fibrosis in our study. HRCT& CECT are the most accurate noninvasive imagingmodality for evaluation of lung parenchyma. Clinical evaluation, chest radiography and Computed Tomography examination should be regarded as integral components of the investigation protocol in patients with various interstitial lung diseases. Hence computed tomography is a standard investigation to identify and quantify pattern and distribution of different lung diseases and also evaluates extent and progression of disease in relation to prognosis and management. REFERENCES 1. Epler GR, McCloud TC, Gaensler EA, Mikus JP, Carrington CB. Normal chest roentgenograms in chronic diffuse infiltrative lung disease. N Engl J Med 1978; 298: Kreel L. Computed tomography of interstitial pulmonary disease. J Computer Assisted Tomogr 1982; 6: Mayo JR, Webb WR, Gould R, et al. High resolution CT of the lungs: an optimal approach. Radiology 1987; 163: High Resolution Computal Tomography Of The Lugs, 2ND Edi.2013, by D.Karthikeyan 10 Int J Res Med. 2017; 6(3); 5-11 e ISSN: p ISSN:

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