Fig-5: Study population

Fig. 5: Study population

• In this study, consisting of 30 IPF patients, 13 were female (43%), and 17 were male(57%)
• Mean ageof the study sample was 60.7.

 Fig-6: Study population- Age distribution

Fig. 6: Study population- Age distribution

Table-1 : HRCT findings in the 30 patients with IPF. 

• Peripheral distribution /sub pleural predominance of lesions seen in all patients. 

Table-2: Mean  of physiological indices and HRCT findings

Table 2: Mean of physiological indices and HRCT findings

(FVC: forced vital capacity; DLCO: diffusing capacity of the lung for carbon monoxide; FEF25-75 %: forced expiratory flow between 25% and 75%; FEV1: forced expiratory volume in one second; and TID: total interstitial disease score .)

• The higher ratio suggests increased elastic force exerted by the connective tissue abnormally deposited in the parenchyma, keeping airways open.
• In our study group  and in the studies of Lopes et al the TID scores  correlated positively  with FEF25-75 / FVC 

Table 3. Correlations between HRCT findings & functional indices. 

Table 3: Correlations between HRCT findings & functional indices.

(FVC: forced vital capacity; DLCO: diffusing capacity of the lung for carbon monoxide; FEF25-75 %: forced expiratory flow between 25% and 75%; FEV1: forced expiratory volume in one second; and TID: total interstitial disease score .)

• Karl Pearson coefficient of correlation was used to examine the correlation in the total study group.
• **. Correlation (Corr.) is significant at the 0.01 level.
• Strongest correlation was observed between TID and percentage of predicted DLCO (negative correlation) (p = 0.001).
• No correlation was observed between either the fibrotic score or pulmonary artery diameter (P.A.) and the functional indices.

Table 4. Correlations between HRCT findings & functional indices.

Table 4: Correlations between HRCT findings & functional indices.

(FVC: forced vital capacity; DLCO: diffusing capacity of the lung for carbon monoxide; FEF25-75 %: forced expiratory flow between 25% and 75%; FEV1: forced expiratory volume in one second; and TID: total interstitial disease score)

• Karl Pearson coefficient of correlation was used to examine the correlation in the total study group
• **. Correlation (Corr.) is significant at the 0.01 level.
• Strongest correlation was observed between TID and percentage of predicted DLCO (negative correlation) (p = 0.001).
• No correlation was observed between either the fibrotic score or pulmonary artery diameter (P.A.) and the functional indices.

Table 5.Correlation in the group having no emphysema

Table 5: Correlation in the group having no emphysema

• Analyzed using Spearman’s rank correlation.
• When patients with significant emphysematous changes were excluded, negative correlation between FVC and TID was observed.

Table 6. Comparison of the overall lung involvement based on DLCO using Independent sample t test

Table 6: Comparison of the overall lung involvement based on DLCO using Independent sample t test

• After grouping into advanced disease and limited disease based on DLCO17,18,19 (DLCO<39 / DLCO> 40) The two-tailed  t test was used to compare the average of TID scores .
• Significant difference was noted in TID values of  both groups.
• Correlation is significant at the 0.05 level .

Fig-7: ROC curve

Fig. 7: ROC curve

• From the ROC curve  plotted based on the data , we found that a cut off value of six could separate the patients with advanced disease with a sensitivity of 85% and specificity of 65%.

Study Limitations 

• In the sample evaluated, surgical biopsy was not performed, requiring that clinical, radiological and functional parameters be adopted as inclusion / exclusion criteria.
• Another limitation was the use of semiquantitative scores to evaluate the extent of abnormalities on HRCT scans, although previous studies showed a perfectly acceptable degree of interobserver variation(Collins et al).