Summary & Conclusion Summary And Conclusion The collagen vascular diseases are a group of immunologically mediated systemic diseases that involve connective tissue at various sites in the body. In collagen vascular disease, many pathologic entities (e.g. UIP, DIP, BOOP, ..) are often found in the lung. With the exception of PSS, two or more of these anomalies may be found. In PSS, the pathologic feature is UIP, which is indistinguishable from that in IPF It was found that Chest radiographs may be normal in up to 10% of patients with documented diffuse interstitial disease. HRCT scans provided a better estimate of the pattern, distribution, and extent of pulmonary fibrosis and showed more extensive honeycombing than did radiographs. Limitation of HRCT includes the presence of inter-slice gaps, suboptimal detection of micronodular infiltration and the distinction of the nodules from vessels seen end on may be difficult. Spiral CT has revolutionized the way in which chest disorders are evaluated. With spiral CT, continuous table feed and synchronous data acquisition generate a volumetric acquisition that can be performed during a single breathrhold. Spiral HRCT is a new technique that combines HRCT acquisition with post processing techniques for the examination of parenchymal lung disease. We found that HRCT is much better than chest radiograph for the assessment of ILD in CVD (HRCT detect honeycomb changes in 28.4%of patients with CVDs while chest x-ray detect it in 16.3% of cases only). Spiral HRCT gives an early detection and an excellent depiction bronchiectasis, Nodules, and honeycombing in patients with CVD than HRCT (Spiral HRCT detect honeycomb changes in 35.9% of patients with CVDs, while HRCT detect these changes in 28.4% of 171