Correlation of Structure and Function in Idiopathic Pulmonary Fibrosis

Abstract

The early stage of idiopathic pulmonary fibrosis (IPF) is thought to involve a smaller number of alveoli and to be characterized predominantly by cellularity and minimal fibrosis, whereas advanced disease involves a large number of alveoli and is characterized predominantly by fibrosis with minimal cellularity. In addition, correlative studies have indicated that prognosis and response to therapy is determined in part by the extent of fibrosis and cellularity. This study was undertaken to determine whether pulmonary function assessment would help distinguish between the cellular and fibrotic phases of this disorder, as determined by a semiquantitative pathology scoring system that comprised four factor scores: fibrosis, cellularity, granulation/connective tissue, and desquamation. Ninety-six untreated patients with biopsy-confirmed IPF (27 never smokers, 32 current smokers, and 37 ex-smokers) were evaluated. In the group as a whole, there was no significant relationship between the fibrosis or the connective/granulation tissue factor scores and any of the physiologic parameters. The DLCO correlated with the "desquamation" and the total pathology scores, whereas the TLC and FVC correlated with the cellularity factor score. In the current smokers, the coefficient of elastic retraction, DLCO/VA, and FEV1/FVC ratio were significantly lower than in never smokers and ex-smokers, and TLC and FVC were higher than in never smokers. Also, the mean cellularity and granulation/connective tissue factor scores were significantly lower, and the desquamation factor score was significantly higher than those in never smokers and ex-smokers. Both age and smoking status were significant for the cellularity factor score, whereas for the connective/granulation tissue factor score, age was not significant but smoking status was.(ABSTRACT TRUNCATED AT 250 WORDS)

Visual score and quantitative CT indices in pulmonary fibrosis: Relationship with physiologic impairment

“…In the UIP group, DL CO and CPI were carried out because they have the strongest correlation with the morphologic extent of disease, histologically and on the CT [3,[6][7][8]. CPI is a new powerful severity variable that accounts for coexisting emphysema, whereas in patients without emphysema on CT, CPI did not reflect the disease extent better than did DL CO [7].…”

“…Nel gruppo UIP, il DL CO e il CPI sono stati ricavati poiché sono gli indici a maggiore correlazione con l'estensione della patologia, valutata sia istologicamente che alla TC [3,[6][7][8]. Il CPI è una nuova efficacie misura funzionale che aggiunge precisione alla valutazione dei pazienti con UIP in quanto rende conto della presenza di enfisema.…”

“…Fornendo immagini dei polmoni per intero, la HRTC (a differenza della valutazione istopatologica) rappresenta uno strumento non invasivo per il monitoraggio dell'estensione della malattia e può anche essere correlata con (PFR), che invece forniscono solo una valutazione globale della funzionalità polmonare. Diversi studi che includevano un numero considerevole di pazienti con fibrosi polmonare idiopatica (IPF), hanno dimostrato forti correlazioni fra i reperti istologici e l'alterazione funzionale [5,6]; tuttavia, queste sono consistentemente più deboli di quelle osservate tra l'alterazione funzionale e gli score TC [3,[7][8][9].…”

“…By providing images of the entire lungs, HRCT (unlike histopathological evaluation) represents a noninvasive tool for monitoring disease extent, and it can be also correlated with PFTs, which provide, instead, a "global statement" of lung function. Several studies including large numbers of idiopathic pulmonary fibrosis (IPF) patients reported strong correlations between histological findings and functional impairment [5,6]; nevertheless, these are consistently weaker than correlations observed between lung function impairment and CT scores [3,[7][8][9].…”

Value of Spirometry in Detecting Volume Restriction in Interstitial Lung Disease Patients

“…From a physiological point of view a greater relative reduction of VC if there is no TLC decrease means a relative increase in residual volume (RV) and RV as % of TLC (RV%TLC) ratio, the pattern characteristic of emphysema. In some patients with ILD, plethysmographic TLC may be augmented towards normal values if there is concomitant small airways disease with air trapping, particularly when the history includes cigarette smoking [2, 4, 5, 6]. …”