Evaluation of Patients with Pulmonary Nodules

One of the most frequent causes for patient referrals for pulmonary examination is the presence of lung nodules. They are small, rounded opacities within the pulmonary interstation tissue. As the spatial resolution of CT scanners has improved, it has been possible to identify pulmonary nodules with smaller dimensions.

Nodules are circular areas that are denser than typical lung tissue and are frequently referred to as “spots on the lung” or “shadows”. They are typically brought on by airborne irritants, scar tissue, or a healed infection. A nodule may occasionally indicate an early stage of lung cancer.

Typically, lung nodules range in size from 5 millimeters to 30 millimeters. A bigger lung nodule, such as one that is 30 millimeters or more, has a higher chance of becoming malignant than one that is smaller.

What causes the appearance of lung nodules?

Noncancerous lung nodules can also arise from:

• Pollutants/irritants in the air like asbestos or silica
• Autoimmune illnesses including sarcoidosis and rheumatoid arthritis
• Fungus-related illnesses like histoplasmosis
• Infections of the respiratory system, such as tuberculosis (TB)

Examining any prior chest imaging scans that are available is one of the most crucial things doctors conduct when analyzing a nodule. If a nodule was present in a past study and it hasn’t grown over time, it’s unlikely to be cancerous.  Nodules located in an upper lung lobe are more likely to be cancerous and those that show strands extending out from the surface—called spiculations—are more dangerous.

Risk factors for lung nodules

Personal risk factors should also be taken into account:

• History of smoking
• Older age
• A history of previous cancer, including lung, head and neck, pancreatic or bladder cancer
• A family history of lung cancer
• A history of treatment with radiation therapy or chemotherapy for lymphoma
• Occupational exposure to dusts, metals or fumes that have been linked to lung cancer
• Lung disease, like COPD or pulmonary fibrosis

Symptoms of lung nodules

Small lung nodules rarely cause symptoms. The patient may cough, wheeze, or have trouble breathing if the growth is blocking his airway. Occasionally, he could also exhibit symptoms of early-stage lung cancer, which hasn’t progressed beyond the lung. More serious signs include:

• Chest pain
• Chronic cough or coughing up blood
• Fatigue
• Hoarseness
• Loss of appetite and unexplained weight loss
• Recurring respiratory infections like bronchitis or pneumonia
• Shortness of breath (dyspnea) or wheezing

Diagnosing Pulmonary Nodules

Finding out if a lung nodule is malignant or benign is the main goal of the diagnostic procedure.

The nodule’s development rate can be used as a reliable indicator of the difference. Benign nodules rarely grow in size. In comparison, malignant nodules might grow by a factor of two every four months on average (some as quickly as 25 days, some as slowly as 15 months). A sequence of X-rays or CT (computed tomography) images taken over a period can be used to assess the growth rate.

The second most reliable approach to tell if it is malignant or benign is evaluating a nodule’s calcification.

Nodules that are benign have a tendency to be more uniformly colored, smoother, and more consistently formed. Nodules that are cancerous are much more prone to have asymmetrical forms, rougher surfaces, and varying colors or spotted patterns like granular, punctate or reticular patterns of calcification.

An imaging finding of calcification in a lung nodule suggests that the lesion is likely benign. However, not all calcified pulmonary nodules are benign, and main central lung carcinoid, metastasis, and primary bronchogenic cancer are among the differential diagnoses. The ability to identify calcification in malignant tumors is now more sensitive because to the widespread use of computed tomography.

The primary radiographic characteristic is that lung nodules are often homogenous and well-defined, because of their sharp borders with normal aerated lung parenchyma surrounding them. Lung nodules may be solitary or multiple. To be considered solitary, a nodule must be completely surrounded by normal lung parenchyma, without associated atelectasis, enlargement of the hilum, or pleural effusion.

X-rays or CT scans often give enough details to make an accurate diagnosis. The nodule’s cells might be collected by medical professionals for a biopsy. Using a needle or by conducting local surgery, cells can be isolated and, in addition with a patient’s sputum analysis, it might offer more reliable information.

There are several different diagnoses for lung nodules. The presence of relevant and important symptoms, the total amount of nodules, and their distinct visualization features (such as their location, shape, the presence of calcifications of various types, and the presence of spiculation or cavitation) may significantly reduce the range of possible diagnoses or even point toward a particular entity:

Malignant

• Bronchogenic lung cancer
• Lymphoma
• Carcinoid
• Sarcoma
• Lung metastases

 Benign

• Hamartoma
• Chondroma
• Lipoma

 Infections

 Immune-mediated diseases (Rheumatoid arthritis , Granulomatosis with polyangiitis ,etc)

Congenital abnormalities

Lung nodules and AI

CT screening for lung cancer can considerably lower the mortality rate for the condition. However, it might be difficult to perform high-quality lung cancer screening in normal clinical setting. In a real-world clinical setting, multiple observers with different clinical experiences perform the image analysis. Sometimes, lung nodules may be missed because of how they look or because of the radiologist’s perception errors, which can be brought on by tiredness, loss of concentration, or unsuitable viewing conditions when there are too many nodules.

Artificial intelligence (AI) systems can assess specific lesions by learning highly discriminative picture characteristics from a large number of medical scans.

Deep learning’s major benefit is its capacity to increase categorization with less direct supervision by learning from the training data. The identification and categorization of lung nodules, the distinction between malignant and benign nodules in the diagnosis, and the staging of lung cancer have all greatly advanced thanks to neural network-based algorithms. AI systems have been combined with PACS to increase the level of automation in the evaluation of lung nodules due to the growing use of technology in clinical settings.

Lung nodules detection with XVision

XVision’s software offers a recognition algorithm that enables radiologists to better detect lung nodules with a diameter between 3 and 30 mm. The results are displayed using an easy-to-read User-Interface allowing higher accuracy in a shorter amount of time. By highlighting the existence of nodules on each slice and individually measuring the diameter and volume of the ones that are found, XVision improves the total time needed to diagnose each patient.

Our CT solutions can be customized to be easily integrated into the hospital infrastructure, allowing a wide and efficient scaling. As a result, medical professionals are empowered to identify high-risk individuals and notify them, by detecting possible malignant nodules during regular check-ups or glancing over historical medical data. We’re enabling seamless process optimization, from preventive monitoring to early detection, emergency care and much more, all from a single CT.

You can also read about how XVision is helping lung cancer detection by clicking here.