A diagnostic workup can include a variety of scans and biopsies. Definition<unk> r density is used to distinguish larger lung tumors, smaller infiltrates or masses with other accompanying characteristics. An often used formal radiological definition is the following: a single lesion in the lung completely surrounded by functional lung tissue with a diameter less than 3 cm and without associated pneumonia, atelectasis (lung collapse) or lymphadenopathies (swollen lymph nodes). CT scan For incidentally detected<unk> s on CT scan, Fleischner Society guidelines are given in table below. For multiple nodes, management is based on the most suspicious node. These guidelines do not apply in lung cancer screening, in patients with immunosuppression, or in patients with known primary cancer. +Solid<unk> s 3) 6-8mm (100-250mm3) >8mm (>250mm3) Single<unk>  Low risk No routine follow-up CT after 6–12 months, then consider CT after 18–24 months Consider CT at 3 months, PET-CT or biopsy High risk Optionally, CT after 12 months CT after 6–12 months, then after 18–24 months Multiple<unk> s Low risk No routine follow-up CT after 3–6 months, then consider CT after 18–24 months High risk Optionally CT after 12 months CT after 3–6 months, then after 18–24 months +Subsolid<unk> s Total size 3) Total size >6mm (>1003) Single<unk>  Ground glass opacity No routine follow-up CT after 6–12 months to check if persistent, then after 2 years and then another 2 years Part solid No routine follow-up CT after 6–12 months: * If unchanged and solid component remains<unk> s CT after 3–6 months. If stable, consider CT after 2 and then another 2 years. CT after 3–6 months, then after 18–24 months More frequent CT scans than what is recommended has not been shown to improve outcomes but will increase radiation exposure and the unnecessary health care can be expected to make the patient anxious and uncertain. PET scan FDG-PET study of a 71-year-old woman with a solitary pulmonary<unk>  (thin arrow) in the left lower lobe near the heart. The scan also revealed abnormal increased activity at the gastro-esophageal junction (thick arrow). The final diagnosis was non-Hodgkin lymphoma at both sites. If there is an intermediate risk of malignancy, further imaging with positron emission tomography (PET scan) is appropriate (if available). It can be done simultaneously as a CT scan in the form of PET-CT. Around 95% of patients with a malignant<unk>  will have an abnormal PET scan, while around 78% of patients with a benign<unk>  will look normal on PET (this is the test sensitivity and specificity). Thus, an abnormal PET scan will reliably pick up cancer, but several other types of<unk> s (inflammatory or infectious, for example) will also show up on a PET scan. If the<unk>  has a diameter of less than one centimeter, PET scans are often avoided because of an increased risk of falsely normal results. Cancerous lesions usually have a high metabolism on PET, as demonstrated by their high uptake of FDG (a radioactive sugar). File:PET-CT of a tuberculoma.PET-CT of a tuberculoma. Other imaging Other potential forms of medical imaging of pulmonary<unk> s include magnetic resonance imaging (MRI) or single photon emission computed tomography (SPECT). Histopathology For cases suspicious enough to proceed to biopsy, small biopsies can be obtained by fine needle aspiration or bronchoscopy are commonly used for diagnosis of<unk> s. CT guided percutaneous transthoracic needle biopsies have also proven to be very helpful in the diagnosis of SPN. In selected cases,<unk> s can also be sampled through the airways using bronchoscopy or through the chest wall using fine-needle aspiration (which can be done under CT guidance). Needle aspiration can only retrieve groups of cells for cytology and not a tissue cylinder or biopsy, precluding evaluation of the tissue architecture. Theoretically, this makes the diagnosis of benign conditions more difficult, although rates higher than 90% have been reported. Complications of the latter technique include hemorrhage into the lung and air leak in the pleural space between the lung and the chest wall (pneumothorax). However, not all these cases of pneumothorax need treatment with a chest tube.
Lung nodule
Lung abscess
Pulmonary consolidation
Lung tumor
Pleural disease
Mediastinal tumors
Pulmonary infiltrate
Malignant pleural effusion