From the Guidelines
Ill-defined opacities on a lung CT scan should be further evaluated with clinical correlation and possibly additional testing to determine the underlying cause, as they may indicate various conditions including infections, inflammation, early-stage tumors, or interstitial lung diseases. These opacities may represent areas of abnormal tissue density that lack clear boundaries, and their appearance relates to their pathophysiology—infections cause inflammatory exudates that appear hazy, while tumors may show as ill-defined masses due to irregular growth patterns and invasion of surrounding tissues 1. The management of ill-defined opacities depends on the underlying cause, patient symptoms, and clinical context. For example, for infectious causes, appropriate antibiotics or antivirals may be prescribed, while for inflammatory conditions, anti-inflammatory medications might be indicated, and for suspected malignancies, biopsy may be required 1.
Key Considerations
- The appearance of ill-defined opacities on CT scans can be indicative of various conditions, including ground-glass opacities, which are areas of increased attenuation through which underlying structures such as vessels remain visible 1.
- High-resolution CT (HRCT) scanning can provide detailed evaluation of the lung parenchyma and help in the diagnosis of interstitial lung diseases, such as idiopathic pulmonary fibrosis (IPF) 1.
- The multidisciplinary approach, including clinical, radiologic, and pathologic findings, is essential for the diagnosis of idiopathic interstitial pneumonias (IIPs) 1.
- Follow-up imaging is often recommended to monitor changes in these opacities over time, which can provide valuable diagnostic information.
Recommendations
- Further evaluation with clinical correlation and possibly additional testing is necessary for accurate diagnosis of ill-defined opacities on lung CT scans.
- Management should be based on the underlying cause, patient symptoms, and clinical context.
- HRCT scanning can be useful in the diagnosis of interstitial lung diseases, but should be interpreted in conjunction with clinical and pathologic findings.
From the Research
Ill-Defined Opacities on Lung CT
- Ill-defined opacities on lung CT can be caused by various conditions, including angiosarcoma, as reported in a case study from 2.
- The study from 2 describes a 74-year-old male with ill-defined nodular infiltrates on chest roentgenogram and bilateral pleural effusion, which was later diagnosed as angiosarcoma.
- Another study from 3 provides a schematic approach to diagnosing multifocal lung opacities in the emergency department, considering distribution on chest X-rays, personal history, clinical examination, laboratory tests, and imaging studies.
Inflammatory Markers and Lung Disease
- Inflammatory markers such as C-reactive protein (CRP) and IgG have been associated with lung disease severity in adult patients with cystic fibrosis, as reported in 4.
- The study from 4 found that CRP and IgG levels correlated with lung function, as measured by forced expiratory volume in 1 second (FEV1).
- Another study from 5 investigated the predictive effects of preoperative complete blood cell count (CBC)-derived inflammatory biomarkers in early-stage non-small-cell lung cancer (NSCLC) and found that monocyte-lymphocyte ratio (MLR) was an independent predictor of shorter recurrence-free survival.
Diagnostic Approach
- A diagnostic approach to ill-defined opacities on lung CT should consider various conditions, including angiosarcoma, and utilize a combination of imaging studies, laboratory tests, and clinical examination, as suggested in 2 and 3.
- Inflammatory markers such as CRP and IgG may be useful in monitoring disease progression and response to therapy in patients with lung disease, as reported in 4.
- Preoperative MLR levels may be a useful predictor of recurrence in patients with early-stage NSCLC, as reported in 5.